ADVANCED AND EVER ADVANCING
MOULDED CASE CIRCUIT BREAKERS
TECHNICAL NOTES
98
A
1
1. INTRODUCTION ............................................... 2
2. FEATURES ....................................................... 3
2.1 Arc-Extinguishing Device – ISTAC.................. 3
2.2 Digital ETR ......................................................... 4
3. CONSTRUCTION AND OPERATION...............6
4. CHARACTERISTICS AND
PERFORMANCE............................................. 11
4.1 Overcurrent-Trip Characteristics ................... 11
4.2 Short-Circuit Trip Characteristics.................. 11
4.3 Effects of Mounting Attitudes ........................ 12
4.4 DC Tripping Characteristics of AC-Rated
MCCBs.............................................................. 12
4.5 Frequency Characteristics ............................. 12
4.6 Switching Characteristics............................... 13
4.7 Dielectric Strength........................................... 13
5. CIRCUIT BREAKERS SELECTION ............... 14
5.1 Circuit Breakers Selection Table ................... 14
6. PROTECTIVE CO-ORDINATION ................... 39
6.1 General ............................................................. 39
6.2 Interrupting Capacity Consideration ............. 40
6.3 Selective-Interruption...................................... 41
6.4 Cascade Back-up Protection.......................... 68
6.5 I2t Let-Through Characteristics and Current
Limiting Characteristics.................................. 70
6.6 Protective Coordination with Wiring ............. 71
6.7 Protective Coordination with
Motor Starters .................................................. 74
6.8 Coordination with Devices on the
High-Voltage Circuit ........................................ 76
7. SELECTION .................................................... 79
7.1 For Motor Branch Circuits .............................. 79
7.2 For Lighting and Heating Branch Circuits .... 79
7.3 For Main Circuit ............................................... 80
7.4 For Welding Circuits ....................................... 80
7.5 For Transformer-Primary Use ........................ 82
7.6 For Capacitor Circuits..................................... 83
7.7 For Thyristor Circuits...................................... 84
7.8 MDU Breaker .................................................... 90
7.9 Selection of MCCBs in inverter circuit .......... 93
8. ENVIRONMENTAL CHARACTERISTICS ...... 95
8.1 Atmospheric Environment.............................. 95
8.2 Vibration-Withstand Characteristics ............. 96
8.3 Shock-Withstand Characteristics .................. 97
9. SHORT-CIRCUIT CURRENT
CALCULATIONS ............................................ 98
9.1 Purpose ............................................................ 98
9.2 Definitions ........................................................ 98
9.3 Impedances and Equivalent Circuits of
Circuit Components ........................................ 98
9.4 Classification of Short-Circuit Current........ 101
9.5 Calculation Procedures ................................ 102
CONTENTS
We have the pleasure of providing all our customers with the technical information for Mitsubishi
moulded case circuit breakers. This indicates the fundamental data of our circuit breakers
regarding the applicable standards, constructional principles, and operational performances.
Please refer to the catalogue of our circuit breakers for details of specifications.
Also please stand in need of the handling and maintenance manual for maintaning the circuit
breakers in service continuously.
We do hope they are available for all our customers to built more efficient systems.
2
1. INTRODUCTION
Mitsubishi Advancing Technology
Mitsubishi, the leading manufacturer of circuit break-
ers, has been providing customers with a wide range
of highly reliable and safe moulded case circuit break-
ers (MCCB) and earth-leakage circuit breakers
(ELCB), corresponding to the needs of the age.
Since production began in 1933 many millions of
Mitsubishi ACBs, MCCBs and MCBs have been sold
throughout many countries.
In 1985 a new design concept for controlling arc en-
ergies within MCCBs – vapour jet control (VJC) – was
introduced and significantly improved performance. It
is provided the technological advance for a new ‘su-
per series’ range of MCCBs and is used in all present
ratings from 3 to 1600 amps.
In 1995 Mitsubishi offers the new PSS (Progressive
Super Series) breakers having ratings from 3 to 250
amps that concentrate the most advanced technolo-
gies into a compact body. Their four major features
are:
• New circuit-breaking technology ISTAC for a higher
current-limiting performance, upgrading the circuit-
breaking capability.
• Electronic circuit breakers with the Digital ETR pro-
tecting the circuit accurately.
• One-frame, one-size design allowing efficient panel
design.
• Cassette-type internal accessories that allow instal-
lation by the user.
Progressive Super Series, an integration of technol-
ogy and know-how from this comprehensive electronic
product manufacturer, will create its own fields of ap-
plication with its excellent performance.
A Brief Chronology
1933 Moulded case circuit breaker production
begins.
1952 Miniature circuit breaker production be-
gins.
1968 Manufacture commences of short-time-
delayed breakers.
1969 Production and sale of first residual cur-
rent circuit breakers.
1970 170kA breaking level ‘permanent power
fuse’ integrated MCCBs is introduced.
1973 Introduction of first short-time delay and
current-limiting selectable breakers go on
sale.
1974 First MELNIC solid-state electronic trip
unit MCCBs are introduced.
1975 ELCBs with solid-state integrated circuit
sensing devices are introduced.
1977-1979 Four new ranges of MCCBs are intro-
duced – economy, standard, current lim-
iting, ultra current limiting and motor rated
designs – a comprehensive coverage of
most application requirements.
1982 Compact ACBs with solid-state trip de-
vices and internally mounted accessories
introduced.
1985-1989 Super series MCCBs with VJC and ETR
are developed and launched – awarded
the prestigious Japanese MInister of Con-
struction Prize.
1990 New 200kA level U-series MCCBs super
current limiting breakers are introduced.
1991 Super-NV ELCBs and Super-AE ACBs
are introduced.
1995 Progressive Super Series 30~250 amps
are introduced.
1997 Progressive Super Series 400~800 amps
are introduced.
3
2. FEATURES – Advanced MCCB Design Technol-
ogy & Performance
2.1 Arc-Extinguishing Device – ISTAC
Mitsubishi has developed an epoch-making ISTAC
technology to realize an improved current-limiting and
breaking performance within a smaller breaking space.
Introduction of ISTAC technology upgrades the cur-
rent-limiting, selective-breaking, and cascade-break-
ing performance. The maximum peak let-through cur-
rent Ip decreases to about 80% (compared with
Mitsubishi’s 100AF). The passing energy I2t de-
creases to about 65% (compared with MItsubishi’s
100AF). The smaller breaking space has led to an
improved function, a smaller size, and a standardiza-
tion of the breakers.
Triple forces accelerating
The triple forces generated by a newly designed cur-
rent pass and the Vapor Jet Control (VJC) insulat-
ing materials which makes up a slot-type breaking
construction accelerate the movable conductor, and
separate the contacts faster than ever before in short-
breaking.
Electromagnetic attractive force which works between
a current of the movable conductor and a current of
the fixed upper conductor.
Electromagnetic repulsive force which works between
a current of the movable conductor and a current of
the fixed lower conductor.
Pressure which works on the movable conductor by
gas generated in the slot.
Lower,
fixed-contact
conductor
Repulsive
force
Movable
contact
Attractive
force
Current A Current
Current B
Current C
Upper,
fixed-contact
conductor
1
2
Arc control by slot-breaking
The VJC of the fixed contact incorporates newly de-
veloped insulation made of ceramic fiber and metal
hydroxide. The substantially improves the VJC effect.
The arc-extinguishing gas energies to improve the
capability of extinguishing the arc.
The VJC suppresses the emergence of carbide prod-
ucts in breaking a current and contribute to the recov-
ery of insulation immediately thereafter.
The VJCs on the fixed and movable contacts work
together to forcefully reduce the arc spot and rapidly
contract the total arc being extinguished.
Fixed contact
VJC
Upper,
fixed-contact
conductor
Lower,
fixed-contact
conductor
Pressure 3
Arc
Movable contact
Movable
contact VJC
Vapor jet control (VJC)
Vapor Jet Controllers made of insulating material are
arranged around the contacts where they control the
arc as follows:
1. The arc spot is forcibly reduced by the arrange-
ment of the insulating material.
2. The arc column is contracted.
3. Adiabatic expansion cools the arc.
4. The arc is transferred at the optimum moment to
the arc-extinguishing chamber by the arrangement
of the Vapor Jet Controllers.
4
2.2 Digital ETR (Electronic Trip Relay)
Mitsubishi’s electronic MCCBs are equipped with a
digital ETR to enable fine protection.
The digital ETR contains Mitsubishi’s original double
IC (8 bit microcomputer and custom-IC).
Digital detection of the effective value
Electronic devices such as an inverter distort the cur-
rent waveform. Mitsubishi’s PSS electronic breakers
are designed to detect digitally the effective value of
the current to minimize over-current tripping errors.
This enables fine protection for the system.
LSW : Long
time-delay
soft ware
PSW : Pre-alarm
soft ware
WDT : Watch-dog
timer
circuit
Power-source side terminal
Load-side
terminal
Breaking mechanism
Rectifying circuit
Test input
Load-current indication LED (70%)
Trip coil
Custom IC
I
CV
PSS
WDT
Microcomputer
CPU
Characteristics
setting part
A/D
convertor
SSW
CT
CT
CT
CT
LSW
PSW
Input and
output
I : Instantaneous
circuit
CV : Constant
voltage
circuit
Phase-
selection
sampling
circuit
Short
time-delay
soft ware
Trigger circuit
Over-current
indication LED
Pre-alarm
indication LED
Pre-alarm
output
Standard equipped pre-alarm system
Mitsubishi’s PSS electronic breakers have a pre-alarm
system as a standard. When the load current exceeds
the set pre-alarm current, the breaker lights up an LED
and outputs a pre-alarm signal.
Load
M
1×10
3
1×10
2
1×10
4
10
2
10
3
10
Time (sec)
10
1
0.1
0.01
I
r
I
P
Pre-alarm
current
Current setting
T
L
Current (A)
I
s
T
s
Load current
High-voltage fuse-
Allowable short-time
characteristics
Short time-delay
tripping current
Short time-delay
operating time
Instantaneous
tripping current
Long time-delay
operating time
Current-Converted value
on the high-voltage side
Switch
with fuse
High
voltage
Low
voltage
Transformer
MCCB
(electronic)
I
i
Processing of the digital ETR
Sampling and A/D
conversion
Calculating
the digitally
effective value
Processing
the long time-delay
pre-alarm
characteristics
5
2.3 Equipment of High Technology
Series
NF-S
NF-C
NF-U
Type
NF30-SP
NF50-HP
NF50-HRP
NF60-HP
NF100-SP
NF100-HP
NF100-SEP
NF100-HEP
NF160-SP
NF160-HP
NF250-SP
NF250-HP
NF250-SEP
NF250-HEP
NF400-SP
NF400-SEP
NF400-HEP
NF400-REP
NF630-SP
NF630-SEP
NF630-HEP
NF630-REP
NF800-SEP
NF800-HEP
NF800-REP
NF1000-SS
NF1250-SS
NF1600-SS
NF50-CP
NF60-CP
NF100-CP
NF250-CP
NF400-CP
NF630-CP
NF800-CEP
NF100-RP
NF100-UP
NF225-RP
NF225-UP
NF400-UEP
NF630-UEP
NF800-UEP
NF1250-UR
Advanced Technology
VJC
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
ISTAC
●
●
●
●
●
●
●
●
●
●
●
●
Digital-ETR
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
Analog-ETR
●
●
●
●
6
3.1 General
The primary components are: a switching mechanism,
an automatic tripping device (and manual trip button),
contacts, an arc-extinguishing device, terminals and
a molded case.
3. CONSTRUCTION AND OPERATION
Fig. 3.1 Type NF100-SP Construction
Handle
1. Trip indication
The automatically tripped condi-
tion is indicated by the handle in
the center position between ON
and OFF, the yellow (or white)
line cannot be seen in this posi-
tion.
2. Resetting
Resetting after tripping is per-
formed by first moving the han-
dle to the OFF position to en-
gage the mechanism, then re-
turning the handle to ON to re-
close the circuit.
3. Trip-Free
Even if the handle is held at
ON, the breaker will trip if an
overcurrent flows.
4. Contact On Mechanism
Even in the worst case in which
welding occurs owing to an
overcurrent, the breaker will trip
and the handle will maintain to
ON, indicating the energizing
state.
ON OFF Trip
Handle indication
Arc-Extinguishing Device
Mitsubishi MCCBs feature excel-
lent arc-extinguishing perfor-
mance by virtue of the optimum
combination of grid gap, shape,
and material.
Trip Button (Push to Trip)
Enables tripping mechanically
from outside, for confirming the
operation of the accessory switch-
es and the manual resetting func-
tion.
Switching Mechanism
The contacts open and close rap-
idly, regardless of the moving
speed of the handle, minimizing
contact wear and ensuring safety.
Rapid
movement
Link-mechanism
operation
Magnetic flux
Arc extinction
Magnetic
force
Grid
Arc
Contact
Molded case
(Base)
Terminal
Molded case
(Cover)
Automatic tripping device
ON
OFF
ON
OFF
7
3.2 Switching Mechanism
The ON, OFF and TRIPPED conditions are shown in
Fig. 3.2. In passing from ON to OFF, the handle ten-
sion spring passes through alignment with the toggle
link (“dead point” condition). In so doing, a positive,
rapid contact-opening action is produced; the OFF to
ON contact closing acts in a similar way (“quick make”
and “quick break” actions). In both cases the action of
the contacts is always rapid and positive, and inde-
pendent of the human element – i.e., the force or
speed of the handle.
In auto tripping a rotation of the bracket releases
the cradle and operates the toggle link to produce the
contact-opening action described above. In the tripped
condition the handle assumes the center position be-
tween on and off, providing a visual indication of the
tripped condition. Also, auto trip is “trip free,” so that
the handle cannot be used to hold the breaker in the
ON condition. The protective contact-opening func-
tion cannot be defeated.
In multipole breakers the poles are separated by
integral barriers in the molded case. The moving con-
tacts of the poles are attached to the central toggle
link by a common-trip bar, however, so that tripping,
opening and closing of all poles is always simulta-
neous. This is the “common trip” feature, by which
single phasing and similar unbalance malfunctions are
effectively prevented.
Spring tension line
Toggle link
Cradle Bracket
Spring
a) On
b) Off
c) Tripped
ON to OFF dead-point line
OFF to ON dead-point line
Handle centered; indicates
tripped condition
Fig. 3.2 Switching Mechanism Action
3.3 Automatic Tripping Device
There are three types of device, the thermal-magnetic
type, the hydraulic-magnetic type and the electronic
trip relay type.
8
■Automatic Tripping Devices
●Thermal-Magnetic Type (100~800A Frame) 1. Time-Delay Operation
An overcurrent heats and warps the bi-
metal to actuate the trip bar.
2. Instantaneous Operation
If the overcurrent is excessive, the
amature is attracted and the trip bar ac-
tuated.
Fig. 3.3
●Thermal-Magnetic Type (1000~4000A Frame) 1. Time-Delay Operation
An overcurrent heats and warps the bi-
metal to actuate the trip bar.
2. Instantaneous Operation
If the overcurrent is excessive, magneti-
zation of the stationary core is strong
enough to attract the armature and ac-
tuate the trip bar.
Fig. 3.4
●Hydraulic-Magnetic Type (30~60A Frame) 1. Time-Delay Operation
At an overcurrent flow, the magnetic
force of the coil overcomes the spring,
the core closes to the pole piece, attracts
the armature, and actuates the trip bar.
The delay is obtained by the viscosity of
silicon oil.
2. Instantaneous Operation
If the overcurrent is excessive, the ar-
mature is instantly attracted, without the
influence of the moving core.
Fig. 3.5
●Principle of Electronic Trip Relay (ETR) Operation 1. The current flowing in each phase is
monitored by a current transformer (CT).
2. Each phase of the transformed current
undergoes full-phase rectification in the
rectifier circuit.
3. After rectification, each of the currents
are converted by a peak-conversion and
an effective-value conversion circuit.
4. The largest phase is selected from the
converted currents.
5. Each time-delay circuit generates a time
delay corresponding to the largest
phase.
6. The trigger circuit outputs a trigger sig-
nal.
7. The trip coil is excited, operating the
switching mechanism.
Fig. 3.6
Armature
Trip bar
Silicon oil
Moving core
Damping spring
Pipe
Coil
Pole piece
Bimetal
Heater
Armature
Trip bar
Latch
Bimetal
Latch
Heater
Stationary core
Armature
Trip bar
Power-source side terminal
Load-side
terminal
Breaking mechanism
Rectifying circuit
Test input
Load-current indication LED (70%)
Trip coil
Custom IC
I
CV
PSS
WDT
Microcomputer
CPU
Characteristics
setting part
A/D
convertor
SSW
LSW
PSW
Input and
output
Trigger circuit
Trigger circuit
Over-current
indication LED
Pre-alarm
indication LED
Pre-alarm
output
CT
CT
CT
CT
CT
CT
CT
Power-supply side terminal
Load-side
terminal Test
terminals Overcurrent display
LED
(1000~1600A Frame)
(100~800A Frame)
Switching mechanism
Trip coil
Peak
conversion
and
largest-phase
selection
Effective value
conversion
and
largest-phase
selection
Test-signal
generator
circuit
Long-
delay
circuit
Short-
delay
circuit
Instan-
taneous
circuit
Special IC
Rectifier circuit
9
Table 3.1 Comparison of Thermal-Magnetic, Hydraulic-Magnetic and Electronic Types
Item
Ambient
temperature
Frequency
Mounting
attitude
Flexibility
of operating
characteristics
Flexibility of
rated current
Thermal-magnetic type
Operating current is affected by ambient
temperature (bimetal responds to absolute
temperature not temperature rise).
Negligible effect up to several hundred Hz;
above that the instantaneous trip is affect-
ed due to increased iron losses.
Negligible effect.
Bimetal must provide adequate deflection
force and desired temperature characteris-
tic. Operating time range is limited.
Units for small rated currents are physically
impractical.
Hydraulic-magnetic type
Affected only to the extent that the damp-
ing-oil viscosity is affected.
Trip current increases with frequency, due
to increased iron losses.
Mounting attitude changes the effective
weight of the magnetic core.
Oil viscosity, cylinder, core and spring
design, etc., allow a wide choice of operat-
ing times.
Coil winding can easily be designed to suit
any ampere rating.
Negligible effect up to 600A;
Above that operating current decreases
due to increase of a fever.
IF distortion is big, minimum operating cur-
rent increases.
Distorted
wave
Electronic type
Within the range of 50(60)~100% of rated
current, any ampere rating are practical.
Also, to lower the value of short-time delay
or instantaneous trip can be easily done
comparatively.
Operating time can be easily shortened.
To lengthen operating time is not.
Negligible effect
Tripping current of some types decrease
due to CT or condition of operating circuit
with high frequency, and others increase.
Negligible effect
For peak value detection, operating current
drops.
Operating time
Current
Operating time
Current
Operating time
Ceiling
Horizontal
ON
ON OFF
OFF
Current
Operating time
Current
Operating time
High frequency
Low frequency
Current
Operating time
High frequency
Low frequency
Current
Operating time
High temperature
Low temperature
Current
Operating time
High temperature
Standard temperature
Low temperature
Current
Operating time
Current
Operating time
Current
Operating time
Current
Above 700A
Operating time
Current
Small current width
Current width
Operating time
Current
Peak value
detection
Operating time
Current
Operating time
Current
10
3.4 Contacts
A pair of contacts comprises a moving contact and a
fixed contact. The instants of opening and closing
impose the most severe duty. Contact materials must
be selected with consideration to three major criteria:
1. Minimum contact resistance
2. Maximum resistance to wear
3. Maximum resistance to welding
Silver or silver-alloy contacts are low in resistance,
but wear rather easily. Tungsten, or majority-tungsten
alloys are strong against wear due to arcing, but rather
high in contact resistance. Where feasible, 60%+ sil-
ver alloy (with tungsten carbide) is used for contacts
primarily intended for current carrying, and 60%+ tung-
sten alloy (with silver) is used for contacts primarily
intended for arc interruption. Large-capacity MCCBs
employ this arrangement, having multicontact pairs,
with the current-carrying and arc-interruption duties
separated.
3.5 Arc-Extinguishing Device
Arcing, an inevitable aspect of current interruption,
must be extinguished rapidly and effectively, in nor-
mal switching as well as protective tripping, to mini-
mize deterioration of contacts and adjacent insulat-
ing materials. In Mitsubishi MCCBs a simple, reliable,
and highly effective “de-ion arc extinguisher,” consist-
ing of shaped magnetic plates (grids) spaced apart in
an insulating supporting frame, is used (Fig. 3.7). The
arc (ionized-path current) induces a flux in the grids
that attracts the arc, which tends to “lie down” on the
grids, breaking up into a series of smaller arcs, and
also being cooled by the grid heat conduction. The
arc (being effectively longer) thus requires far more
voltage to sustain it, and (being cooler) tends to lose
ionization and extinguish. If these two effects do not
extinguish the arc, as in a very large fault, the elevated
temperature of the insulating frame will cause gas-
sing-out of the frame material, to de-ionize the arc.
Ac arcs are generally faster extinguishing due to the
zero-voltage point at each half cycle.
3.6 Molded Case
The integral molded cases used in Mitsubishi MCCBs
are constructed of the polyester resin containing glass
fibers, the phenolic resin or glass reinforced nylon.
They are designed to be suitably arc-, heat- and gas-
resistant, and to provide the necessary insulating
spacings and barriers, as well as the physical strength
required for the purpose.
3.7 Terminals
These are constructed to assure electrical efficiency
and reliability, with minimized possibility of localized
heating. A wide variety of types are available for ease
of mounting and connection. Compression-bonded
types and bar types are most commonly used.
3.8 Trip Button
This is a pushbutton for external, mechanical tripping
of the MCCB locally, without operating the external-
accessory shunt trip or undervoltage trip, etc. It en-
ables easy checking of breaker resetting, control-cir-
cuit devices associated with alarm contacts, etc., and
resetting by external handle.
Supporting
frame
Grids
Fig. 3.7 The De-Ion Arc Extinguisher
Grid
Arc
Attraction force
Induced flux
Fig. 3.8 The Induced-Flux Effect
11
4.1 Overcurrent-Trip Characteristics (Delay
Tripping)
Tripping times for overcurrents of 130 and 200% of
rated current are given in Table 4.1, assuming ambi-
ent temperatures of 40°C, a typical condition inside
of panelboards. The figures reflect all poles tested to-
gether for 130% tripping, and 105% non-tripping.
Within the range of the long-delay-element (thermal
or hydraulic) operation, tripping times are substan-
tially linear, in inverse relationship to overcurrent mag-
nitude.
The tripping times are established to prevent ex-
cessive conductor-temperature rise; although times
may vary among MCCBs of different makers, the lower
limit is restricted by the demands of typical loads: tung-
sten-lamp inrush, starting motor, mercury-arc lamps,
etc. The tripping characteristics of Mitsubishi MCCBs
are established to best ensure protection against ab-
normal currents, while avoiding nuisance tripping.
4.1.1 Ambient Temperature and Thermal Tripping
Fig. 4.1 is a typical ambient compensation curve
(curves differ according to types and ratings), show-
ing that an MCCB rated for 40°C ambient use must
be derated to 90% if used in a 50°C environment. In
an overcurrent condition, for the specified tripping time,
tripping would occur at 180% rated current, not 200%.
At 25°C, for the same tripping time, tripping would
occur at 216%, not 200%.
4.1.2 Hot-State Tripping
The tripping characteristics described above reflect
“cold-state tripping” – i.e., overloads increased from
zero – and the MCCB stabilized at rated ambient. This
is a practical parameter for most uses, but in intermit-
tent operations, such as resistance welding, motor
pulsing, etc., the “hot state” tripping characteristic must
be specified, since over-loads are most likely to oc-
cur with the MCCB in a heated state, while a certain
load current is already flowing.
Where the MCCB is assumed to be at 50% of rat-
ing when the overload occurs, the parameter is called
the 50% hot-state characteristic; if no percentage is
specified, 100% is assumed. Hot-state ratings of 50%
and 75% are common.
4.2 Short-Circuit Trip Characteristics (In-
stantaneous Tripping)
For Mitsubishi MCCBs with thermal-magnetic trip units
the instantaneous-trip current can be specified inde-
pendently of the delay characteristic, and in many
cases this parameter is adjustable offering consider-
able advantage in coordination with other protection
and control devices. For example, in coordination with
motor starters, it is important to set the MCCB instan-
taneous-trip element at a lower value than the fusing
(destruction) current of the thermal overload relay
(OLR) of the starter.
For selective tripping, it must be remembered that
even though the branch-MCCB tripping time may be
shorter than the total tripping time of the main MCCB,
in a fault condition the latter may also be tripped be-
cause its latching curve overlaps the tripping curve of
the former. The necessary data for establishing the
required compatibility is provided in the Mitsubishi
MCCB sales catalogues.
The total clearing time for the “instantaneous” trip-
ping feature is shown in Fig. 4.3; actual values differ
for each MCCB type.
Table 4.1 Overcurrent Tripping Times
Rated current
(A)
30 or less
31~63
64~100
101~250
251~400
401~630
631~800
801~1000
1001~1250
1251~1600
1601~2000
2001~4000
Tripping time
(minutes, max.)
200%
8.5
4
8.5
8
10
12
14
16
18
20
22
24
130%
60
60
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
60
60
120
105%
Non-Tripping time
(minutes, max.)
20 25
Ambient temperature (:)
% rating compensation
30 40
110 108
100
50 60
90
80
120
Fig. 4.1 Typical Temperature-Compensation Curve
Cold state
Operating time
Current
Hot state
Fig. 4.2 Hot-State-Tripping Curve
4. CHARACTERISTICS AND PERFORMANCE
12
Total
clearing
time
Latching
(relay)
time
Electromagnet
oparating
time
Time for
contacts to
open
Arc-
extinguishing
time
Mechanical
delay
time
Arcing
time
Fig. 4.3 Instantaneous Tripping Sequence
4.3 Effects of Mounting Attitudes
Instantaneous tripping is negligibly affected by mount-
ing attitude, for all types of MCCB. Delay tripping is
also negligibly affected in the thermal types, but in
the hydraulic-magnetic types the core-weight effect
becomes a factor. Fig. 4.4 shows the effect, for verti-
cal-surface mounting and for two styles of horizontal-
surface mounting.
(vertical plane)
100%
93%
ON
ON
ON
ON
ON
ON
ON
ON
90%110%
93%
107%
107%
100%
Fig. 4.5 Effects of Nonvertical-Plane Mounting on Current
Rating
4.4 DC Tripping Characteristics of AC-Rated MCCBs
Table 4.2 DC Tripping Characteristics
Trip unit
Thermal
magnetic
Hydraulic
magnetic
Long delay
No effect below 630A
frame. Above this, AC
types cannot be used
for DC.
DC minimum-trip
values are 110~140%
of AC values.
Instantaneous
DC inst.-trip current is
approx. 130% of AC
value.
Tripping curve
AC
DC
Overcurrent
Tripping time
AC
DC
Tripping time
Overcurrent
4.5 Frequency Characteristics
At commercial frequencies the characteristics of
Mitsubishi MCCBs of below 630A frame size are vir-
tually constant at both 50Hz and 60Hz (except for the
E Line models, the characteristics of MCCBs of 800A
frame and above vary due to the CT used with the
delay element).
At high frequencies (e.g., 400Hz), both the current
capacity and delay tripping curves will be reduced by
skin effect and increased iron losses.
Performance reduction will differ for different types;
at 400Hz it will become 80% of the rating in breakers
of maximum rated current for the frame size, and 90%
of the rating in breakers of half of the maximum rating
for the frame size.
The instantaneous trip current will gradually in-
crease with frequency, due to reverse excitation by
eddy currents. The rise rate is not consistent, but
around 400Hz it becomes about twice the value at
60Hz. Mitsubishi makes available MCCBs especially
designed for 400Hz use. Apart from operating char-
acteristics they are identical to standard MCCBs (S
Line).
Floor-mounted
Overcurrent
Tripping time
Ceiling-mounted
Wall-mounted
(horiz. or vert. attitude)
Fig. 4.4 Effect of Mounting Attitude on the Hydraulic-
Magnetic MCCB Tripping Curves
13
4.6 Switching Characteristics
The MCCB, specifically designed for protective inter-
ruption rather than switching, and requiring high-con-
tact pressure and efficient arc-extinguishing capabil-
ity, is expected to demonstrate inferior capability to
that of a magnetic switch in terms of the number of
operations per minute and operation life span. The
specifications given in Table 4.3 are applicable where
the MCCB is used as a switch for making and break-
ing rated current.
Electrical tripping endurance in MCCBs with shunt
or undervoltage tripping devices is specified as 10%
of the mechanical-endurance number of operations
quoted in IEC standards.
Shunt tripping or undervoltage tripping devices are
intended as an emergency trip provision and should
not be used for normal circuit-interruption purposes.
4.7 Dielectric Strength
In addition to the requirements of the various interna-
tional standards, Mitsubishi MCCBs also have the
impulse-voltage withstand capabilities given below
(Table 4.4). The impulse voltage is defined as sub-
Table 4.3 MCCB Switching Endurance
Frame size
100 or less
225
400, 630
800
1000~2000
2500, 3000
3200, 4000
Operations per hour
120
120
60
20
20
10
10
Number of operations
Without current
8500
7000
4000
2500
2500
1500
1500
With current
1500
1000
1000
500
500
500
500
Total
10000
8000
5000
3000
3000
2000
2000
stantially square-wave, with a crest length of
0.5~1.5µsec and a tail-length of 32~48µsec. The volt-
age is applied between line and load terminals (MCCB
off), and between live parts and ground (MCCB on).
Table 4.4 MCCB Impulse Withstand Voltage (Uimp)
Line Type
Impulse-voltage (kA)
MB
NF
S
C
U
MB30-SP MB50-CP MB-50-SP
MB100-SP MB225-SP
NF30-CS
NF400-CP NF630-CP NF800-CEP
NF50-CP NF60-CP NF100-CP NF250-CP
NF100-RP NF100-UP NF225-RP NF225-UP
NF400-SP NF400-SEP NF400-HEP NF400-REP NF630-SP NF630-SEP
NF630-HEP NF630-REP NF800-SEP NF800-HEP NF800-REP
NF800-REP NF1000-SS NF1250-SS NF1600-SS
MB30-CS 4
6
6
8
6
6
4
8
8
NF30-SP NF50-HP NF60-HP
NF50-HRP NF100-SP NF100-HP NF100-SEP NF100-HEP
NF160-SP NF160-HP NF250-SP NF250-HP NF250-SEP NF250-HEP
NF400-UEP NF630-UEP NF800-UEP
14
5. CIRCUIT BREAKER SELECTION
5.1 Circuit Breaker Selection Table
Following Table shows various characteristics of each breaker to consider selection and coordination with
upstream devices or loads.
Characteristics
Standard : Standard characteristics MCCBs
Low-inst : Low-inst. MCCBs for Discrimination
When a power fuse (PF) is used as a high-voltage protector, it must be coordinated
with an MCCBs on the secondary side.
Generator: Generator-Protection MCCBs
These MCCBs have long-time-delay operation shorter than standard type and low
instantaneous operation.
Mag-Only : Magnetic trip only MCCBs
These are standard MCCBs minus the thermal tripping device. They have no time-
delay tripping characteristic, providing protection only against large-magnitude short-
circuit faults.
PF short-time tolerancs
capacity
Pf.
Tr.
MCCB1
MCCB2
Time
MCCB
operating
characteristic
curve
Low-inst.MCCBs
Current
15
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
Frame (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
CIRCUIT BREAKER SELECTION TABLE 30
NF30-CS
3, 5, 10, 15, 20, 30
500
–
–
1.5/1.5 (415V)
1.5/1.5 (380V)
2.5/2 (240V)
23
–
–
–
–
–
–
–
–
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
NF30-SP
3, 5, 10, 15, 20, 30
600
–
2.5/1
2.5/1
5/2
5/2
23
–
–
–
–
–
–
23
Magnetic
Fixed ampere rating
instantaneous
50
10, 15, 20, 30, 40, 50
600
–
2.5/1
2.5/1
5/2
5/2
23
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
–
–
––
–
–
–
Magnetic
Fixed ampere rating
instantaneous
23
NF50-CP
330±6
550±10
10 100 ±20
15 150 ±30
20 200 ±40
30 300 ±60
339±17
566±28
10 132 ±57
15 198 ±86
20 265 ±115
30 397 ±172
333±10
555±17
10 110 ±35
15 165 ±52
20 220 ±70
30 330 ±105
10 110 ±35
15 165 ±52
20 220 ±70
30 330 ±105
40 440 ±140
50 550 ±175
10 100 ±20
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
16
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
50
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
–
–
–
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
NF50-HP
10, 15, 20, 30, 40, 50
600
–
7.5/4
10/5
10/5
25/13
234
234
60
NF60-CP
10, 15, 20, 30, 40, 50, 60
600
–
2.5/1
2.5/1
5/2
5/2
23
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
–
–
–
–
–
–
23
Magnetic
Fixed ampere rating and
instantaneous
10 110 ±35
15 165 ±52
20 220 ±70
30 330 ±105
40 440 ±140
50 550 ±175
10 110 ±35
15 165 ±52
20 220 ±70
30 330 ±105
40 440 ±140
50 550 ±175
60 660 ±210
10 100 ±20
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
10 100 ±20
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
60 600 ±120
17
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
60
NF60-HP
10, 15, 20, 30, 40, 50, 60
600
–
7.5/4
10/5
10/5
25/13
234
–
–
–
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
100
Thermal, magnetic
Fixed ampere rating and
instantaneous
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
Thermal, magnetic
Fixed ampere rating and
instantaneous
23
50 300 ±60
60 360 ±72
75 450 ±90
100 600 ±120
–
–
234 2 3
Magnetic
Fixed ampere rating and
instantaneous
NF100-CP NF100-SP
15, 20, 30, 40, 50, 60, 75, 100
690
–
15/8
25/13
30/15
50/25
234
50, 60, 75, 100
600
–
7.5/4
10/5
10/5
25/13
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
10 110 ±35
15 165 ±52
20 220 ±70
30 330 ±105
40 440 ±140
50 550 ±175
60 660 ±210
50 750 ±150
60 900 ±180
75 1125 ±225
100 1500 ±300
10 100 ±20
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
60 600 ±120
50 500 ±100
60 600 ±120
75 750 ±150
100 1000 ±200
15 225 ±45
20 300 ±60
30 450 ±90
40 600 ±120
50 750 ±150
60 900 ±180
75 1125 ±225
100 1500 ±300
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
–
15 90 ±18
20 120 ±24
30 180 ±36
40 240 ±48
50 300 ±60
60 360 ±72
75 450 ±90
100 600 ±120
–
–
–
234
Magnetic
Fixed ampere rating and
instantaneous
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
60 600 ±120
75 750 ±150
100 1000 ±200
18
Type
Frame (A) 100
NF100-CP T/A
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Rated insulation voltage Ui (V) AC
Rated current In (A)
15 ~ 20 225 ±45
20 ~ 25 300 ±60
25 ~ 40 375 ±75
40 ~ 63 600 ±120
63 ~ 80 945 ±189
80 ~ 100 1200 ±240
50
NF50-HRP
–
–
–
–
–
–
–
–
–
Thermal, magnetic
Fixed ampere rating and
instantaneous
15 225 ±45
20 300 ±60
30 450 ±90
40 600 ±120
50 750 ±150
–
–
–
–
–
–
23
Magnetic
Fixed ampere rating and
instantaneous
100
NF100-SP T/A
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
–
–
–
–
–
–
–
–
–
600
–
7.5/4
10/5
10/5
25/13
23
15 ~ 20, 20 ~ 25, 25 ~ 40
40 ~ 63, 63 ~ 80, 80 ~ 100
15, 20, 30, 40, 50
15 ~ 20, 20 ~ 25, 25 ~ 40
40 ~ 63, 63 ~ 80, 80 ~ 100
690
2.5/1
20/10
30/15
30/15
85/43
23
690
–
15/8
25/13
30/15
50/25
234
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
15 ~ 20 225 ±45
20 ~ 25 300 ±60
25 ~ 40 375 ±75
40 ~ 63 600 ±120
63 ~ 80 945 ±189
80 ~ 100 1200 ±240
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
19
Type
Frame (A) NF100-HP T/ANF100-HP
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Thermal, magnetic
Fixed ampere rating and
instantaneous
15 225 ±45
20 300 ±60
30 450 ±90
40 600 ±120
50 750 ±150
60 900 ±180
75 1125 ±225
100 1500 ±300
–
–
–
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
234
Rated insulation voltage Ui (V) AC
5/3
30/15
50/25
50/25
100/50
234
690
15, 20, 30, 40, 50, 60, 75, 100
Rated current In (A) 15 ~ 20, 20 ~ 25, 25 ~ 40
40 ~ 63, 63 ~ 80, 80 ~ 100
690
– (5/3) ₎
30/15
50/25
50/25
100/50
234
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
–
–
–
–
–
–
–
–
–
NF100-RP
15, 20, 30, 40, 50, 60, 75, 100
690
–
42/42
125/125
125/125
125/125
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
15 ~ 20 225 ±45
20 ~ 25 300 ±60
25 ~ 40 375 ±75
40 ~ 63 600 ±120
63 ~ 80 945 ±189
80 ~ 100 1200 ±240
15 225 ±45
20 300 ±60
30 450 ±90
40 600 ±120
50 750 ±150
60 900 ±180
75 1125 ±225
100 1500 ±300
–
–
–
–
–
–
–
–
–
100
15 150 ±30
20 200 ±40
30 300 ±60
40 400 ±80
50 500 ±100
60 600 ±120
75 750 ±150
100 1000 ±200
₎ To be agreed soon.
20
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Standard
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
100
15, 20, 30, 40, 50, 60, 75, 100
690
10/5
200/200
200/200
200/200
200/200
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
30 ~ 50, 60 ~ 100
690
–
15/8
25/13
30/15
50/25
34
NF100-UP NF100-SEP
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
30 60-75-90-105-120-150-
180-210-240-300
40 80-100-120-140-160-
200-240-280-320-400
50 100-125-150-175-200-
250-300-350-400-500
60 120-150-180-210-240-
300-360-420-480-600
75 150-187.5-225-262.5-300-
375-450-525-600-750
100 200-250-300-350-400-
500-600-700-800-1000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In ~ 16 In
30 ~ 50 200 ~ 800
60 ~100 400 ~1600
Rating (A) and
Inst. (A) 15 225 ±45
20 300 ±60
30 450 ±90
40 600 ±120
50 750 ±150
60 900 ±180
75 1125 ±225
100 1500 ±300
Low-inst Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
Generator Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles –
–
Mag-Only Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
–
–
–
3
–
–
–
–
NF100-HEP
30 ~ 50, 60 ~ 100
690
5/3
30/15
50/25
50/25
100/50
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
30 60-75-90-105-120-150-
180-210-240-300
40 80-100-120-140-160-
200-240-280-320-400
50 100-125-150-175-200-
250-300-350-400-500
60 120-150-180-210-240-
300-360-420-480-600
75 150-187.5-225-262.5-300-
375-450-525-600-750
100 200-250-300-350-400-
500-600-700-800-1000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In ~16 In
30 ~ 50 200 ~ 800
60 ~100 400 ~1600
–
–
3
–
–
–
–
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Rating: 30 ~50A, 60 ~100A
Inst. : Operating characteristics
must be adjusted as
follows.
STD ≤ 3 (Is setting)
LTD : minimum setting
(TL = 12sec setting)
Rating: 30 ~50A, 60 ~100A
Inst. : Operating characteristics
must be adjusted as
follows.
STD ≤ 3 (Is setting)
LTD : minimum setting
(TL = 12sec setting)
21
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
160
NF160-SP
125, 150, 160
690
–
15/8
25/13
30/15
50/25
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
–
–
–
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
125 1250 ±250
160 1600 ±320
NF160-SP T/A
100 ~ 125, 125 ~ 160
690
–
15/8
25/13
30/15
50/25
234
Thermal, magnetic
Adjustable ampere rating and
fixed instantaneous
–
–
–
–
–
–
–
–
–
NF160-HP
125, 150, 160
690
5/3
30/8
50/13
50/13
100/25
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
125 1750 ±350
150 2100 ±420
160 2240 ±448
100 ~ 125 1400 ±280
125 ~ 160 1400 ±280
125 1750 ±350
150 2100 ±420
160 2240 ±448
–
–
–
–
–
–
234 234
Magnetic
Fixed ampere rating and
instantaneous
125 1250 ±250
160 1600 ±320
22
Type
Frame (A) 160
NF160-HP T/A 250
NF250-CP
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
–
–
–
–
–
–
–
–
–
Thermal, magnetic
Fixed ampere rating and
instantaneous
125 1750 ±350
150 2100 ±420
175 2450 ±490
200 2800 ±560
225 3150 ±630
250 2500 ±500
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
6 4 I In
125 750 ±150 500 ±100
150 900 ±180 600 ±120
175 1050 ±210 700 ±140
200 1200 ±240 800 ±160
225 1350 ±270 900 ±180
250 1500 ±300 1000 ±200
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
23
125 1250 ±250
150 1500 ±300
175 1750 ±350
200 2000 ±400
225 2250 ±450
250 2250 ±450
690
– (10/5) ₎
30/8 (30/15) ₎
50/13 (50/25) ₎
50/13 (50/25) ₎
100/25 (100/50) ₎
234
600
–
10/5
15/8
18/9
30/15
23
Rated insulation voltage Ui (V) AC
Rated current In (A)
NF250-CP T/A
100 125, 125 160
150 200, 200 250
125, 150, 175, 200, 225, 250100 125, 125 160
600
–
10/5
15/8
18/9
30/15
23
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
100 125 1400 ±280
125 160 1400 ±280 100 125 1400 ±280
125 160 1400 ±280
150 200 2100 ±420
200 250 2500 ±500
–
–
–
–
–
–
–
–
–
₎ To be agreed soon.
~ ~ ~
~ ~
~
~
~
~
~
~
~
n
23
Type
Frame (A) 250
NF250-SP
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
6 In4 In
125 750 ±150 500 ±100
150 900 ±180 600 ±120
175 1050 ±210 700 ±140
200 1200 ±240 800 ±160
225 1350 ±270 900 ±180
250 1500 ±300 1000 ±200
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
125 1250 ±250
150 1500 ±300
175 1750 ±350
200 2000 ±400
225 2250 ±450
250 2250 ±450
Rated insulation voltage Ui (V) AC
Rated current In (A)
690
–
15/8
25/13
30/15
50/25
234
125, 150, 175, 200, 225, 250
NF250-SP T/A
100 125, 125 160
150 200, 200 250
690
–
–
25/20
30/22
50/42
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
125 1750 ±350
150 2100 ±420
175 2450 ±490
200 2800 ±560
225 3150 ±630
250 2500 ±500
–
–
–
–
–
–
–
–
–
NF250-HP
125, 150, 175, 200, 225, 250
690
5/3
30/8
50/13
50/13
100/25
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
100 125 1400 ±280
125 160 1400 ±280
150 200 2100 ±420
200 250 2500 ±500
234 234
Magnetic
Fixed ampere rating and
instantaneous
–
–
–
–
–
–
125 1750 ±350
150 2100 ±420
175 2450 ±490
200 2800 ±560
225 3150 ±630
250 2500 ±500
125 1250 ±250
150 1500 ±300
175 1750 ±350
200 2000 ±400
225 2250 ±450
250 2250 ±450
~
~ ~
~
~
~
~
~
24
Type
Frame (A) 250
Low-inst
Standard
Mag-Only
Generator
690V
500V
440V
400V
230V
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Rated insulation voltage Ui (V) AC
Rated current In (A) 100 125, 125 160
150 200, 200 250
690
– (10/5) ₎
30/8 (30/15) ₎
50/13 (50/25) ₎
50/13 (50/25) ₎
100/25 (100/50) ₎
234
Thermal, magnetic
Adjustable ampere rating and
fixed instantaneous
100 125 1400 ±280
125 160 1400 ±280
150 200 2100 ±420
200 250 2500 ±500
–
–
–
–
–
–
–
–
–
NF225-RPNF250-HP T/A
125, 150, 175, 200, 225
690
–
42/42
125/125
125/125
125/125
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Thermal, magnetic
Fixed ampere rating and
instantaneous
125 1750 ±350
150 2100 ±420
175 2450 ±490
200 2800 ±560
225 3150 ±630
125 1750 ±350
150 2100 ±420
175 2450 ±490
200 2800 ±560
225 3150 ±630
690
10/5
200/200
200/200
200/200
200/200
234
125, 150, 175, 200, 225
NF225-UP
225
₎ To be agreed soon.
~
~ ~
~
~
~
~
~
25
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Standard
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Low-inst Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
250
Automatic tripping
device
Rating (A) and
Inst. (A)
Generator Number of poles
Mag-Only Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
125 250-312.5-375-437.5-500-
625-750-875-1000-1250
150 300-375-450-525-600-
750-900-1050-1200-1500
175 350-437.5-525-612.5-700-
875-1050-1225-1400-1750
200 400-500-600-700-800-1000-
1200-1400-1600-2000
225 450-562.5-675-787.5-900-
1125-1350-1575-1800-2250
250 500-625-750-875-1000-
1250-1500-1750-2000-2500
Instantaneous pick up current
Variation is within ±15% of
setting current
4 14 In
125 250 1000 3500
–
NF250-HEP
125-250
690
5/3
30/8
50/13
50/13
100/25
34
–
3
–
–
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
125 250-312.5-375-437.5-500-
625-750-875-1000-1250
150 300-375-450-525-600-
750-900-1050-1200-1500
175 350-437.5-525-612.5-700-
875-1050-1225-1400-1750
200 400-500-600-700-800-1000-
1200-1400-1600-2000
225 450-562.5-675-787.5-900-
1125-1350-1575-1800-2250
250 500-625-750-875-1000-
1250-1500-1750-2000-2500
Instantaneous pick up current
Variation is within ±15% of
setting current
4 14 In
125 250 1000 3500
–
NF250-SEP
125-250
690
–
15/8
25/13
30/15
50/25
34
–
3
–
–
–
–
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Rating: 125 250A
Inst. : Operating characteristics
must be adjusted as
follows.
STD ≤ 3 (Is setting)
LTD : minimum setting
(TL = 12sec setting)
Rating: 125 250A
Inst. : Operating characteristics
must be adjusted as
follows.
STD ≤ 3 (Is setting)
LTD : minimum setting
(TL = 12sec setting)
~ ~
~~ ~
~
~~
26
Type
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
Rated insulation voltage Ui (V) AC
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
400A NF400-SEP
200 400
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
200 400-500-600-700-800-
1000-1200-1400-1600-
2000
225 450-562.5-675-787.5-
900-1125-1200-1500-
1800-1350-1575-1800-
2250
250 500-625-750-875-1000-
1250-1500-1750-2000-
2500
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 16 In
1600 6400
690
10/10
30/30
42/42
45/45
85/85
Rated current In (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
NF400-CP
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
250, 300, 350, 400
600
–
15/8
25/13
36/18
50/25
250 2500 ±500
300 3000 ±600
350 3500 ±700
400 4000 ±800
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
6 In4 In
250 1500±300 1000±200
300 1800±360 1200±240
350 2100±420 1400±280
400 2400±480 1600±320
23
Magnetic
Fixed ampere rating and
instantaneous
250 2500 ±500
300 3000 ±600
350 3500 ±700
400 4000 ±800
–
–
–
NF400-SP
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
250, 300, 350, 400
690
10/10
30/30
42/42
45/45
85/85
250 3500 ±700
300 4200 ±840
350 4900 ±980
400 5600 ±1120
234
Magnetic
Fixed ampere rating and
instantaneous
250 2500 ±500
300 3000 ±600
350 3500 ±700
400 4000 ±800
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
~
~
~
27
Type
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
Rated insulation voltage Ui (V) AC
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
400A NF400-UEP
Rated current In (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
NF400-HEP NF400-REP
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
200 400
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
200 400-500-600-700-800-
1000-1200-1400-1600-
2000
225 450-562.5-675-787.5-
900-1125-1200-1500-
1800-1350-1575-1800-
2250
250 500-625-750-875-1000-
1250-1500-1750-2000-
2500
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 16 In
1600 6400
690
35/35
170/170
200/200
200/200
200/200
200 400
adjustable
3
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
200 400-500-600-700-800-
1000-1200-1400-1600-
2000
225 450-562.5-675-787.5-
900-1125-1200-1500-
1800-1350-1575-1800-
2250
250 500-625-750-875-1000-
1250-1500-1750-2000-
2500
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 16 In
1600 6400
690
15/10
70/35
125/63
125/63
150/75
200 400
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
200 400-500-600-700-800-
1000-1200-1400-1600-
2000
225 450-562.5-675-787.5-
900-1125-1200-1500-
1800-1350-1575-1800-
2250
250 500-625-750-875-1000-
1250-1500-1750-2000-
2500
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 16 In
1600 6400
690
10/10
50/50
65/65
70/70
100/100
~~ ~
~
~
~
~
~
~
28
Type
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
Rated insulation voltage Ui (V) AC
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
630A NF630-SEP
Rated current In (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
NF630-CP NF630-SP
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
300 630
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
630 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 15 In
2520 9450
690
10/10
30/30
42/42
45/45
85/85
500, 600, 630
234
Thermal, magnetic
adjustable ampere rating and
fixed instantaneous
500 Lo 2500 ±500
2 4000
3 5500
Hi 7000 ±1400
600 Lo 3000 ±600
2 4800
3 6600
Hi 8400 ±1680
630 Lo 3150 ±630
2 5040
3 6930
Hi 8820 ±1764
690
10/10
30/30
42/42
45/45
85/85
500, 600, 630
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
500 5000 ±1000
600 6000 ±1200
630 6300 ±1260
600
–
18/9
36/18
36/18
50/25
23
Magnetic
Fixed ampere rating and
instantaneous
500 5000 ±1000
600 6000 ±1200
630 6300 ±1260
234
Thermal, magnetic
adjustable ampere rating and
fixed instantaneous
500 Lo 2000 ±400
2 3000
3 4000
Hi 5000 ±1000
600 Lo 2400 ±480
2 3600
3 4800
Hi 6000 ±1200
630 Lo 2520 ±504
2 3780
3 5040
Hi 6300 ±1260
~
~~
29
Type
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
Rated insulation voltage Ui (V) AC
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
630A
Rated current In (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
NF630-UEP
300 630
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
630 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 15 In
2520 9450
690
35/35
170/170
200/200
200/200
200/200
NF630-REP
300 630
adjustable
3
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
630 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 15 In
2520 9450
690
20/15
70/35
125/63
125/63
150/75
NF630-HEP
300 630
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
300 600-750-900-1050-1200-
1500-1800-2100-2400-
3000
350 700-875-1050-1225-
1400-1750-2100-2450-
2800-3500
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
630 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 15 In
2520 9450
690
15/15
50/50
65/65
70/70
100/100
~ ~ ~
~~
~~
~~
30
Type
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
Rated insulation voltage Ui (V) AC
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
800A
Rated current In (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
NF800-HEP
400 800
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
450 900-1150-1350-1575-
1800-2250-2700-3150-
3600-4500
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
700 1400-1750-2100-2450-
2800-3500-4200-4900-
5600-6300
800 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 12 In
3200 9600
690
15/15
50/50
65/65
70/70
100/100
NF800-SEP
400 800
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
450 900-1150-1350-1575-
1800-2250-2700-3150-
3600-4500
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
700 1400-1750-2100-2450-
2800-3500-4200-4900-
5600-6300
800 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 12 In
3200 9600
690
10/10
30/30
42/42
45/45
85/85
NF800-CEP
400 800
adjustable
3
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
450 900-1150-1350-1575-
1800-2250-2700-3150-
3600-4500
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
700 1400-1750-2100-2450-
2800-3500-4200-4900-
5600-6300
800 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 12 In
3200 9600
600
–
18/9
36/18
36/18
50/25
Electronic trip relay
Adjustable ampere rating,
instantaneous pick up current
34
Instantaneous pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
~ ~ ~
~~
~~
~~
31
Type
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
Rated insulation voltage Ui (V) AC
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
800A
Rated current In (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
–
–
–
–
–
–
NF800-UEP
400 800
adjustable
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
450 900-1150-1350-1575-
1800-2250-2700-3150-
3600-4500
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
700 1400-1750-2100-2450-
2800-3500-4200-4900-
5600-6300
800 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 12 In
3200 9600
690
35/35
170/170
200/200
200/200
200/200
–
–
–
–
–
–
–
–
–
NF800-REP
400 800
adjustable
3
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
400 800-1000-1200-1400-
1600-2000-2400-2800-
3200-4000
450 900-1150-1350-1575-
1800-2250-2700-3150-
3600-4500
500 1000-1250-1500-1750-
2000-2500-3000-3500-
4000-5000
600 1200-1500-1800-2100-
2400-3000-3600-4200-
4800-6000
700 1400-1750-2100-2450-
2800-3500-4200-4900-
5600-6300
800 1260-1575-1890-2205-
2520-3150-3780-4410-
5040-6300
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In 12 In
3200 9600
690
20/15
70/35
125/63
125/63
150/75
–
–
–
~ ~
~~
~~
32
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Solid-state
Adjustable ampere rating
Adjustable short time delay pick up
Fixed instantaneous pick up
Short time delay pick up current
Variation is within ±10% of the setting current
5-7.5-10 In
500 2500-3750-5000
600 3000-4500-6000
700 3500-5250-7000
800 4000-6000-8000
900 4500-6750-9000
1000 5000-7500-10000
Instantaneous pick up current 20000
NF1000-SS
1000
500-600-700-800-900-1000
690
25/13
65/33
85/43
85/43
125/63
34
34
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
34
Variation is within ±10% of the setting current
5-7.5-10 In 3-4.5-6 In 2-3-4 In
500 2500-3750-5000 1500-2250-3000 1000-1500-2000
600 3000-4500-6000 1800-2700-3600 1200-1800-2400
700 3500-5250-7000 2100-3150-4200 1400-2100-2800
800 4000-6000-8000 2400-3600-4800 1600-2400-3200
900 4500-6750-9000 2700-4050-5400 1800-2700-3600
1000 5000-7500-10000 3000-4500-6000 2000-3000-4000
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
Variation is within ±10% of the setting current
3-4.5-6 In 2-3-4 In
500 1500-2250-3000 1000-1500-2000
600 1800-2700-3600 1200-1800-2400
700 2100-3150-4200 1400-2100-2800
800 2400-3600-4800 1600-2400-3200
900 2700-4050-5400 1800-2700-3600
1000 3000-4500-6000 2000-3000-4000
34
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
Variation is within ±10% of the setting current
5-7.5-10 In
500 2500-3750-5000
600 3000-4500-6000
700 3500-5250-7000
800 4000-6000-8000
900 4500-6750-9000
1000 5000-7500-10000
+4000
–2000
33
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Solid-state
Adjustable ampere rating
Adjustable short time delay pick up
Fixed instantaneous pick up
Short time delay pick up current
Variation is within ±10% of the setting current
5-7.5-10 In
600 3000-4500-6000
700 3500-5250-7000
800 4000-6000-8000
1000 5000-7500-10000
1200 6000-9000-12000
1250 6250-9375-12500
Instantaneous pick up current 20000
NF1250-SS
1250
600-700-800-1000-1200-1250
690
25/13
65/33
85/43
85/43
125/63
34
34
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
34
Variation is within ±10% of the setting current
5-7.5-10 In 3-4.5-6 In 2-3-4 In
600 3000-4500-6000 1800-2700-3600 1200-1800-2400
700 3500-5250-7000 2100-3150-4200 1400-2100-2800
800 4000-6000-8000 2400-3600-4800 1600-2400-3200
1000 5000-7500-10000 3000-4500-6000 2000-3000-4000
1200 6000-9000-12000 3600-5400-7200 2400-3600-4800
1250 6250-9375-12500 3750-5625-7500 2500-3750-5000
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
Variation is within ±10% of the setting current
3-4.5-6 In 2-3-4 In
600 1800-2700-3600 1200-1800-2400
700 2100-3150-4200 1400-2100-2800
800 2400-3600-4800 1600-2400-3200
1000 3000-4500-6000 2000-3000-4000
1200 3600-5400-7200 2400-3600-4800
1250 3750-5625-7500 2500-3750-5000
34
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
Variation is within ±10% of the setting current
5-7.5-10 In
600 3000-4500-6000
700 3500-5250-7000
800 4000-6000-8000
1000 5000-7500-10000
1200 6000-9000-12000
1250 6250-9375-12500
+4000
–2000
34
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
240V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Solid-state
Adjustable ampere rating
Adjustable short time delay pick up
Fixed instantaneous pick up
Short time delay pick up current
Variation is within ±10% of the setting current
5-7.5-10 In
600 3000-4500-6000
700 3500-5250-7000
800 4000-6000-8000
1000 5000-7500-10000
1200 6000-9000-12000
1250 6250-9375-12500
Instantaneous pick up current 20000
NF1250-UR
1250
600-700-800-1000-1200-1250
690
–
85/42
125/65
125/65
170/85
34
+4000
–2000
–
–
–
–
–
–
–
–
–
35
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
(Inst trip only)
Generator
690V
500V
440V
400V
230V
Frame (A)
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Solid-state
Adjustable ampere rating
Adjustable short time delay pick up
Fixed instantaneous pick up
Short time delay pick up current
Variation is within ±10% of the setting current
3-4.5-6 In
800 2400-3600-4800
1000 3000-4500-6000
1200 3600-5400-7200
1400 4200-6300-8400
1500 4500-6750-9000
1600 4800-7200-9600
Instantaneous pick up current 20000
NF1600-SS
1600
800-1000-1200-1400-1500-1600
690
25/13
65/33
85/43
85/43
125/63
34
34
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
34
Variation is within ±10% of the setting current
3-4.5-6 In 2-3-4 In
800 2400-3600-4800 1600-2400-3200
1000 3000-4500-6000 2000-3000-4000
1200 3600-5400-7200 2400-3600-4800
1400 4200-6300-8400 2800-4200-5600
1500 4500-6750-9000 3000-4500-6000
1600 4800-7200-9600 3200-4800-6400
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
Variation is within ±10% of the setting current
3-4.5-6 In 2-3-4 In
800 2400-3600-4800 1600-2400-3200
1000 3000-4500-6000 2000-3000-4000
1200 3600-5400-7200 2400-3600-4800
1400 4200-6300-8400 2800-4200-5600
1500 4500-6750-9000 3000-4500-6000
1600 4800-7200-9600 3200-4800-6400
34
Solid-state
Adjustable ampere rating
Adjustable instantaneous pick up
Variation is within ±10% of the setting current
3-4.5-6 In
800 2400-3600-4800
1000 3000-4500-6000
1200 3600-5400-7200
1400 4200-6300-8400
1500 4500-6750-9000
1600 4800-7200-9600
+4000
–2000
36
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Low-inst
Standard
Mag-Only
Generator
600V
500V
415V
380V
240V
Frame (A)
AC Interrupting
capacity (kA rms)
IEC157-1
P1/P2
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
2000
Thermal, adjustable-magnetic
Fixed ampere rating and
adjustable instantaneous
–
–
–
–
–
–
Adjustable-magnetic
Fixed ampere rating and
adjustable instantaneous
NF2000-S NFE2000-S
1800, 2000
600
–
65/50
85/50
85/50
125/85
34
1200-1400-1600-1800-2000
600
–
65/50
85/50
85/50
125/85
34
Solid-state
Adjustable ampere rating,
adjustable short time delay pick up
and fixed instantaneous pick up
34
–
–
–
–
–
–
–
–
–
2500
NF2500-S
2500
600
–
65/50
85/50
85/50
125/85
3
Thermal, adjustable-magnetic
Fixed ampere rating and
adjustable instantaneous
–
–
–
–
–
–
3
Adjustable-magnetic
Fixed ampere rating and
adjustable instantaneous
Variation is within ±10% of the
Hi setting current
Lo 1 2 3
1800 3200-4000-4800-5600-
45Hi
6400-7200-8000
Lo 1 2 3
2000 3200-4000-4800-5600-
45Hi
6400-7200-8000
Variation is within ±10% of the
Hi setting current
Lo 1 2 3
2500 4000-5000-6000-7000-
45Hi
8000-9000-10000
Variation is within ±10% of the
Hi setting current
Lo 1 2 3
2000 3200-4000-4800-5600-
45Hi
6400-7200-8000
Variation is within ±10% of the
Hi setting current
Lo 1 2 3
2500 4000-5000-6000-7000-
45Hi
8000-9000-10000
Specifty frequency
Short time delay pick up current
Variation is within ±10% of the
setting current
3-4.5-6 In
1200 3600-5400-7200
1400 4200-6300-8400
1600 4800-7200-9600
1800 5400-8100-10800
2000 6000-9000-12000
Instantaneous pick up current
30000 ± 3000
37
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Standard
600V
500V
415V
380V
240V
Frame (A)
AC Interrupting
capacity (kA rms)
IEC157-1
P1/P2
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
3000 (3200)
NF3200-S
2800, 3000, 3200
600
–
65/50
85/50
85/50
125/85
3
Thermal, adjustable-magnetic
Fixed ampere rating and adjustable instantaneous
Low-inst Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
Generator Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles –
–
Mag-Only Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
3
NFE3000-S
1800-2000-2500-3000
600
–
65/50
85/50
85/50
125/85
3
Adjustable-magnetic
Fixed ampere rating and adjustable instantaneous
Short time delay pick up current
Variation is within ±10% of the
setting current
2-3-4 In
1800 3600-5400-7200
2000 4000-6000-8000
2500 5000-7500-10000
3000 6000-9000-12000
Instantaneous pick up current
30000 ± 3000
Solid-state
Adjustable ampere rating,
adjustable short time delay pick up
and fixed instantaneous pick up
–
–
–
–
–
–
–
–
–
Variation is within ±10% of the Hi setting current
Lo 1 2 3 4 5 Hi
2800 5000-6600-8300-10000-11600-13300-15000
3000 5000-6600-8300-10000-11600-13300-15000
3200 5000-6600-8300-10000-11600-13300-15000
Variation is within ±10% of the Hi setting current
Lo 1 2 3 4 5 Hi
3000 5000-6600-8300-10000-11600-13300-15000
3200 5000-6600-8300-10000-11600-13300-15000
Specifty frequency
–
38
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
Standard
600V
500V
415V
380V
240V
Frame (A)
AC Interrupting
capacity (kA rms)
IEC157-1
P1/P2
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
4000
NF4000-S
3600, 4000
600
–
65/50
85/50
85/50
125/85
3
Thermal, adjustable-magnetic
Fixed ampere rating and adjustable instantaneous
Low-inst Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
Generator Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles –
–
Mag-Only Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
3
–
NFE4000-S
2500-3000-3500-4000
600
–
65/50
85/50
85/50
125/85
3
Adjustable-magnetic
Fixed ampere rating and adjustable instantaneous
Variation is within ±10% of the Hi setting current
Lo 1 2 3 Hi
4000 8300-10000-11600-13300-15000
Solid-state
Adjustable ampere rating,
adjustable short time delay pick up
and fixed instantaneous pick up
–
–
–
–
–
–
–
–
–
Variation is within ±10% of the Hi setting current
Lo 1 2 3 Hi
3600 8300-10000-11600-13300-15000
4000 8300-10000-11600-13300-15000
Specifty frequency
Short time delay pick up current
Variation is within ±10% of the
setting current
2-3-4 In
2500 5000-7500-10000
3000 6000-9000-12000
3500 7000-10500-14000
4000 8000-12000-16000
Instantaneous pick up current
35000 ± 3500
39
6. PROTECTIVE CO-ORDINATION
6.1 General
Type of System
The primary purpose of a circuit protection system is to prevent damage to series connected equipment and to
minimise the area and duration of power loss. The first consideration is whether an air circuit breaker or moul-
ded case circuit breaker is most suitable.
The next is the type of system to be used. The three major types are:
Fully Rated, Selective and Cascade Back-Up.
Fully Rated
This system is highly reliable, as all of the breakers are rated for the maximum fault level at the point of their
installation. Discrimination (selective interruption) can be incorporated in some cases. The disadvantage is that
high cost branch breakers may be necessary.
Selective-Interruption(Discrimination)
Selective Interruption requires that in the event of a fault, only the device directly before the fault will trip, and
that other branch circuits of the same or higher level will not be affected. The range of selective Interruption of
the main breaker varies considerably depending on the breaker used.
Cascade Back-Up Protection
This is an economical approach to the use of circuit breakers, whereby only the main (upstream) breaker has
adequate interrupting capacity for the maximum available fault current. The mccb’s downstream cannot handle
this maximum fault current and rely on the opening of the upstream breaker for protection.
The advantage of the cascade back-up approach is that it facilitates the use of low cost, low fault level breakers
downstream, thereby offering savings in both the cost and size of equipment.
As Mitsubishi mccb’s have a very considerable current limiting effect, they can be used to provide this ‘cascade
back-up’ protection for downstream circuit breakers.
40
6.2 Interrupting Capacity Consideration
Table 1 230VAC
30
50·60
100
400
630
800
30 or less 50~75 100 150~300
20 or less 30~50 75 100~150 200~500 –
2.5 5 10 15 25 30 35 50 85 100 125 170 200
NF30-
CS
NF50-CP
NF60-CP NF50-HP, NF60-HP NF50-HRP
NF100-CP
NF250-CP
NF400-CP
NF630-CP
NF800-CEP
NF160-SP
NF250-SP
NF250-SEP
NF400-SP, NF400-SEP
NF100-HP
NF100-HEP
NF160-HP
NF250-HP
NF250-HEP
NF100-UP
NF225-UP
30 or less 50~100 150~300 500~1000 1500~2000 2500~5000
400
30
50·60
630
800
2.5 12585655035307.5 10 15 18 25
Table 2 440VAC
100
NF250-CP
NF400-CP
NF1000-SS~NF1600-SS, NF2000-S~NF4000-S
NFE2000-S, NFE3000-S, NFE4000-S
NF800-SEP
NF800-REP
NF225-UP
NF630-REP
NF630-CP
NF800-CEP
NF225-RP
200
NF30-
SP
3ph trans.
capacity (kVA)
Interrupting
capacity
(kA)(sym)
1ph trans.
capacity (kVA)
NF100-SP
NF100-SEP
NF1000-SS~NF1600-SS, NF2000-S~NF4000-S
NFE2000-S, NFE3000-S, NFE4000-S
NF800-SEP
NF800-UEP
NF630-UEP
NF400-UEP
2000~3000500~1500
160
250
~
Trans. capacity
(kVA)
Interrupting
capacity
(kA)(sym)
NF50-CP
NF60-CP NF50-HP
NF60-HP NF50-HRP
NF630-SP,
NF630-SEP
NF100-CP
NF160-HP
NF250-HP
NF250-HEP
NF160-SP
NF250-SP
NF250-SEP
NF100-RP
NF100-HP
NF100-HEP
NF100-SP
NF100-SEP
Frame (A)
1000
4000
~
160
250
~
1000
4000
~
NF1250-
UR
NF100-
RP
NF225-
RP
NF1250-
UR
NF630-SP,
NF630-SEP
Frame (A)
NF100-UP
C Series S Series
1.5
NF30-SP
NF30-CS
NF400-SP, NF400-SEP
NF400-REP
NF400
-HEP NF400
-REP
NF630
-HEP NF630
-REP
NF800
-HEP NF800
-REP
NF800
-HEP
NF630
-HEP
NF400
-HEP
NF800-UEP
NF630-UEP
NF400-UEP
41
<How to see the table>
Example 1
All rated current of branch breaker, type NF30-SP can
fully discriminate with all rated current of main breaker,
type NF400-SEP up to the fault levels, 5kA that is the
interrupting capacity of type NF30-SP.
Example 3
Some rated current of branch breaker, type
NF100-CP having low-inst. trip can discriminate
with some rated current of main breaker, type
NF400-SEP as shown by a deep color up
to the fault levels, 7.5kA. 6 denotes that the
short time delay pick up current of the main
breaker, type NF400-SEP is set at 6 ✕ Ir notch
or higher.
Example 2
Some rated current of branch breaker, type NF160-
SP can discriminate with some rated current of main
breaker, type NF630-SEP as shown by a deep color
up up to the fault levels, 10kA. 6 denotes that
the short-time delay pick up current of the main
breaker, type NF630-SEP is set at 6 ✕ Ir notch or
higher.
6.3 Selective-Interruption (Discrimination)
6.3.1 Selective-Interruption Combination
Following tables show combinations of main-circuit
selective coordination breakers and branch breakers
and the available selective tripping current at the set-
ting points at the branch-circuits.
3
5
10
15
20
30
Icu (kA)
Rated current
(A)
Type
Icu(kA)
5
NF400-SEP
85
200 225 250 300 350 400
5
Main Breaker
Selective limit current
NF30-SP
Type
Branch Breaker
Short-circuit point
Continuous supply
Healthy circuit
Main breaker
Branch breaker
Type
125
150
160
Icu (kA)
Rated current
(A)
Type
Icu(kA)
NF630-SEP
50
300 350 400 500 600 630
10
Main Breaker
Selective limit current
25NF160-SP
Branch Breaker
8
6
87
6
76
5
65
4
54
3
43.5
3
4
Type
Branch Breaker
NF100-CP
Icu (kA)
Rated current
(A)
Type
Icu(kA)
NF400-SEP
50
200 225 250 300 350 400
Main Breaker
50
60
75
100
7.5
Selective limit current
10
440VAC
440VAC
6
5
7
10
5
5
7
10
5
4
6
8
4
3.5
5
7
3.5
3
4
6
3
2.5
3.5
5
Selection Conditions
1. The main breaker rated current, STD operating time
and INST pickup current are to be set to the maxi-
mum values.
2. When selecting the over-current range, also check
the conformity using the other characteristic curves.
Main breaker
STD pick up current.
Set up STD operating time in the
maximum value.
Set up inst pick up current
in the maximum value.
Branch
breaker
230VAC
42
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
230VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP
50 50
Type Icu(kA)
125 150 175 200 225 25030 40 50 60 75 100
Icu: Rated breaking capacity
Selective limit current
BH-D6
Type B 6
6
10
13
16
20
25
32
40
50
63
2.5
3
3.5 2.5
3 2.5
0.8 1.6
5
6
7
10
3.5
5
6
7
3
3.5
5
6
2.5
3
4
5
2.5
3
42.5
3
3.5
2.5
Selective limit current
BH-D6
Type C 6
6
10
13
16
20
25
32
40
50
63
3
3.5
5
6
7
3
3.5
4
5
2.5
3
3.5
4
2.5
3
3.5 2.5
3 2.5
0.8 1.6
10 7
8
10
6
7
8
10
5
6
7
10
4
5
6
7
3
3.5
5
6
3.5
2.5
3
3.5
5
2.5
3
3.5
2.5
2.5
3.5 2.5
3 2.5 2.5
Selective limit current
BH-D10
Type B 10
6
10
13
16
20
25
32
40
50
63
2.5
3
3.5 2.5
3 2.5
0.8 1.6
5
6
7
10
3.5
5
6
7
3
3.5
5
6
2.5
3
4
5
2.5
3
42.5
3
3.5
2.5
Selective limit current
BH-D10
Type C 10
6
10
13
16
20
25
32
40
50
63
3
3.5
5
6
7
3
3.5
4
5
2.5
3
3.5
4
2.5
3
3.5 2.5
3 2.5
0.8 1.6
10 7
8
10
6
7
8
10
5
6
7
10
4
5
6
7
3
3.5
5
6
3.5
2.5
3
3.5
5
2.5
3
3.5
2.5
2.5
3.5 2.5
3 2.5 2.5
43
44
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
230VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP NF400-SEP NF630-SEP
50 50 85 85
Type Icu(kA)
125 150 175 200 225 25030 40 50 60 75 100 300 350 400 500 600 630200 225 250 300 350 400
Selective limit current
NF30-SP 5
3
5
10
15
20
30
4
6
8
3
5
6
10
2.5
3.5
5
7
3
4
6
2.5
3
52.5
3.5
0.8 1.6
3 2.5
3.5 5 5
Selective limit current
NF50-CP 5
10
15
20
30
40
50
4
6
8
3
5
6
10
2.5
3.5
5
7
10
3
4
6
8
10
2.5
3
5
6
8
2.5
3.5
5
6
0.8 1.6
3
4
5
2.5
3
43
3.5 2.5
3 2.5 2.5
3.5
2.5
3 2.5 2.5
5
5
Selective limit current
NF50-HP 25
10
15
20
30
40
50
4
6
8
3
5
6
10
2.5
3.5
5
7
10
3
4
6
8
10
2.5
3
5
6
8
2.5
3.5
5
6
0.8 1.6
3
4
5
2.5
3
43
3.5 2.5
3 2.5 2.5
3.5
2.5
3 2.5 2.5
10 20
Selective limit current
NF60-CP 5
60 10 7
1.6 6543.533
3.5 3.5 3 3 2.5
52.5 5
Selective limit current
NF60-HP 25
60 10 7
1.6 6543.533
3.5 3.5 3 3 2.5
10 2.5 20
Selective limit current
NF100-CP 25
50
60
75
100
8
10 7
8
10
6
7
8
5
6
7
10
5
5
7
10
4
5
6
8
3.5 5
6
7
10
5
5
7
10
4
5
6
8
3.5
4
5
7
3
3.5
4
6
2.5
3
3.5
5
7.5 2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
42.5
3 2.5 2.5
10
Selective limit current
NF100-SP 50
15
20
30
40
50
60
75
100
2.5
3
5
6
8
10
2.5
4
5
7
8
10
2.5
3.5
5
6
7
8
3
4
5
6
7
10
2.5
3
4
5
6
8
2.5
3.5
5
5
7
10
3.5
3
4
5
6
7
10
2.5
3.5
5
5
7
10
2.5
3
4
5
6
8
2.5
3.5
4
5
7
2.5
3
3.5
5
2.5
3
3.5
4
6
7.5
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
42.5
3 2.52.5
15
Selective limit current
NF100-SP
T/A 50
15 20
20 25
25 40
40 63
63 80
80 100
2.5
3
4
6
10
2.5
3.5
5
8
10
2.5
3
5
7
10
2.5
4
6
8
2.5
3.5
6
7
3
5
6
3.5
2.5
4
6
8
2.5
3.5
6
8
3
5
6
2.5
4
5
2.5
3.5
53
4
7.5
2.5
3.5
53
3.5 2.5
3.5 2.5 2.5
15
Selective limit current
NF100-HP 100
15
20
30
40
50
60
75
100
2.5
3
5
6
8
10
2.5
4
5
7
8
10
2.5
3.5
5
6
7
8
3
4
5
6
7
10
2.5
3
4
5
6
8
2.5
3.5
5
5
7
10
3.5
3
4
5
6
7
10
3.5
3.5
5
5
7
10
2.5
3
4
5
6
8
2.5
3.5
4
5
7
2.5
3
3.5
5
2.5
3
3.5
4
6
10
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
42.5
3 2.52.5
25
Selective limit current
NF100-HP
T/A 100
15 20
20 25
25 40
40 63
63 80
80 100
2.5
3
4
6
10
2.5
3.5
5
8
10
2.5
3
5
7
10
2.5
4
6
8
2.5
3.5
6
7
3
5
6
3.5
2.5
4
6
8
2.5
3.5
6
8
3
5
6
2.5
4
5
2.5
3.5
53
4
10
2.5
3.5
53
3.5 2.5
3.5 2.5 2.5
25
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
45
Icu(kA)
Type
Rated current
(A)
NF800-CEP NF800-SEP NF1000-SS NF1250-SS
50 85 125 125
400 450 500 600 700 800400 450 500 600 700 800 600 700 800 1000 1200 1250
NF1600-SS
125
800 1000 1200 1400 1500 1600500 600 700 800 900 1000
Selective limit current
3
5
10
15
20
30
55555
Selective limit current
10
15
20
30
40
50
55555
Selective limit current
10
15
20
30
40
50
20 20 25 25 25
Selective limit current
60 55555
Selective limit current
60 20 20 25 25 25
50
60
75
100
Selective limit current
2.5
3
42.5
3.5 2.5
3 2.5 2.5
10
2.5
3
42.5
3.5 2.5
3 2.5 2.5
15 2525 25
Selective limit current
15
20
30
40
50
60
75
100
2.5
3
42.5
3.5 2.5
3 2.5 2.5
15
2.5
3
42.5
3.5 2.5
3 2.5 2.5
15 50 50 50
Selective limit current
20 25
15 20
25 40
40 63
63 80
80 100
2.5
3.5 2.5
3 2.5 2.5
15
2.5
3.5 2.5
2.5 2.5
15 50 50 50
Selective limit current
15
20
30
40
50
60
75
100
2.5
3
42.5
3.5 2.5
3 2.5 2.5
25
2.5
3
42.5
3.5 2.5
3 2.5 2.5
25 100 100 100
Selective limit current
20 25
15 20
25 40
40 63
63 80
80 100
2.5
3.5 2.5
3 2.5 2.5
25
2.5
3.5 2.5
2.5 2.5
25 100 100 100
Branch Breaker
Main Breaker
Type Icu(kA)
NF30-SP 5
NF50-CP 5
NF50-HP 25
NF60-CP 5
NF60-HP 25
NF100-CP 25
NF100-SP 50
NF100-SP
T/A 50
NF100-HP 100
NF100-HP
T/A 100
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
46
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
230VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP NF400-SEP NF630-SEP
50 50 85 85
Type Icu(kA)
125 150 175 200 225 25030 40 50 60 75 100 300 350 400 500 600 630200 225 250 300 350 400
Selective limit current
NF100-SEP 50
30
40
50
60
75
100
2.5
3.5
5
6
7
10
3
3.5
5
6
8
2.5
3
3.5
5
6
2.5
3
3.5
4
6
2.5
3
3.5
5
2.5
3.5
5
3.5
2.5
3
3.5
4
6
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
3.5 2.5
33
7.5
2.5
3
3.5 2.5
3 3 2.5
15
Selective limit current
NF100-HEP 100
30
40
50
60
75
100
2.5
3.5
5
6
7
10
3
3.5
5
6
8
2.5
3
3.5
5
6
2.5
3
3.5
4
6
2.5
3
3.5
5
2.5
3.5
5
3.5
2.5
3
3.5
4
6
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
3.5 2.5
33
10
2.5
3
3.5 2.5
3 3 2.5
25
Selective limit current
NF160-SP 50
125
150
160
10 10 8
10
3.5 10 10 8
10
10
7
8
8
6
7
7
6.4 6
8
8
6
7
7
5
6
6
4
5
5
3
4
4
3
3.5
4
10
Selective limit current
NF160-SP
T/A 50
100 125
125 160 10
10 10
10 8
87
7
3.5 10
10 8
87
76
65
55
5
6.4 5
55
54
43
33
32.5
2.5
10
Selective limit current
NF160-HP 100
125
150
160
10 10 8
10
3.5 10 10 8
10
10
7
8
8
6
7
7
6.4 6
8
8
6
7
7
5
6
6
4
5
5
3
4
4
3
3.5
4
10
Icu: Rated breaking capacity
Selective limit current
NF160-HP
T/A 100
100 125
125 160 10
10 10
10 8
87
7
3.5 10
10 8
87
76
65
55
5
6.4 5
55
54
43
33
32.5
2.5
10
Selective limit current
NF250-CP 30
125
150
175
200
225
250
10 10 8
10
10
7
8
10
10
10
6
7
8
10
10
8
6.4 6
8
8
10
10
6
7
7
10
10
8
5
6
6
8
8
7
4
5
5
6
7
6
3
4
4
5
6
5
3
3.5
4
5
6
4
7.5
Selective limit current
NF250-CP
T/A 30
100 125
125 160
150 200
200 250
10
10 8
87
76
6
10
5
5
8
10
5
5
7
8
6.4 5
5
8
10
5
5
7
8
4
4
6
7
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
4
7.5
Selective limit current
NF250-SP 50
125
150
175
200
225
250
10 10 8
10
10
7
8
10
10
10
6
7
8
10
10
8
6.4 6
8
8
10
10
6
7
7
10
10
8
5
6
6
8
8
7
4
5
5
6
7
6
3
4
4
5
6
5
3
3.5
4
5
6
4
10
Selective limit current
NF250-SP
T/A 50
100 125
125 160
150 200
200 250
10
10 8
87
76
6
10
5
5
8
10
5
5
7
8
6.4 5
5
8
10
5
5
7
8
4
4
6
7
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
4
10
Selective limit current
NF250-HP 100
125
150
175
200
225
250
10 10 8
10
10
7
8
10
10
10
6
7
8
10
10
8
6.4 6
8
8
8
10
6
7
7
7
10
8
5
6
6
6
8
7
4
5
5
5
6
6
3
4
4
4
5
5
3
3.5
3.5
4
5
4
10
Selective limit current
NF250-HP
T/A 100
100 125
125 160
150 200
200 250
10
10 8
87
76
6
10
5
5
8
10
5
5
7
8
6.4 5
5
8
10
5
5
7
8
4
4
6
7
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
4
10
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
47
Icu(kA)
Type
Rated current
(A)
NF800-CEP NF800-SEP NF1000-SS NF1250-SS
50 85 125 125
400 450 500 600 700 800400 450 500 600 700 800 600 700 800 1000 12001250
NF1600-SS
125
800 1000 1200 1400 1500 1600500 600 700 800 900 1000
Selective limit current
30
40
50
60
75
100
3 2.5 2.5
15
3 2.5 2.5
18 50 50 50
Selective limit current
30
40
50
60
75
100
3 2.5 2.5
25
3 2.5 2.5
35 100 100 100
Selective limit current
125
150
160
5
6
6
4
5
5
4
5
5
3
4
4
3
3.5
3.5
2.5
3
3
10
5
6
6
4
5
5
4
5
5
3
4
4
3
3.5
3.5
2.5
3
3
10
7.5
7.5
50
4.5
4.5
5050
Selective limit current
100 125
125 160
4
43.5
3.5 3
32.5
2.5 2.5
2.5
10
4
43.5
3.5 3
32.5
2.5 2.5
2.5
10 50 50 50
Selective limit current
125
150
160
5
6
6
4
5
5
4
5
5
3
4
4
3
3.5
3.5
2.5
3
3
10
5
6
6
4
5
5
4
5
5
3
4
4
3
3.5
3.5
2.5
3
3
10
7.5
7.5
50
4.5
4.5
5050
Selective limit current
100 125
125 160
4
43.5
3.5 3
32.5
2.5 2.5
2.5
10
4
43.5
3.5 3
32.5
2.5 2.5
2.5
10 50 50 50
Selective limit current
125
150
175
200
225
250
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
7.5
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
7.5
7.5 7.5 7.5
7.5 7.5
25
7.5 7.5
7.5 7.5
25
4.5
4.5
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5 4.5
25
100 125
125 160
150 200
200 250
Selective limit current
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
7.5
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
7.5 2525
4.5
4.5 4.5
25
Selective limit current
125
150
175
200
225
250
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
7.5 7.5 7.5
7.5 7.5
50
7.5 7.5
7.5 7.5
50
4.5
4.5
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5 4.5
50
100 125
125 160
150 200
200 250
Selective limit current
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10 5050
4.5
4.5 4.5
50
Selective limit current
125
150
175
200
225
250
5
6
7
8
8
9
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
7.5 7.5 7.5
7.5 7.5
50
7.5 7.5
7.5 7.5
50
4.5
4.5
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5 4.5
50
100 125
125 160
150 200
200 250
Selective limit current
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10 5050
4.5
4.5 4.5
50
Branch Breaker
Main Breaker
Type Icu(kA)
NF100-SEP 50
NF100-HEP 100
NF160-SP 50
NF160-SP
T/A 50
NF160-HP 100
NF160-HP
T/A 100
NF250-CP 30
NF250-CP
T/A 30
NF250-SP 50
NF250-SP
T/A 50
NF250-HP 100
NF250-HP
T/A 100
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
48
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
230VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP NF400-SEP NF630-SEP
50 50 85 85
Type Icu(kA)
125 150 175 200 225 25030 40 50 60 75 100 300 350 400 500 600 630200 225 250 300 350 400
Selective limit current
NF250-SEP 50
125
150
175
200
225
250
7
8
10
6
7
8
10
6
7
8
10
10
5
6
6
7
8
10
4
5
6
6
7
8
3.5
4
5
6
6
7
6.4 5
6
6
7
8
10
4
5
6
6
7
8
3.5
4
5
6
6
7
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3.5
4
5
10
Selective limit current
NF250-HEP 100
125
150
175
200
225
250
7
8
10
6
7
8
10
6
7
8
10
10
5
6
6
7
8
10
4
5
6
6
7
8
3.5
4
5
6
6
7
6.4 5
6
6
7
8
10
4
5
6
6
7
8
3.5
4
5
6
6
7
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3.5
4
5
10
Selective limit current
NF400-CP 50
250
300
350
400
10 8
10 7
8
10
6
7
8
10
5
6
6
7
4
5
6
7
9.5
Selective limit current
NF400-SP 85
250
300
350
400
10 8
10
10
6
8
10
10
6
7
8
10
9.5
Selective limit current
NF400-SEP 85
200
225
250
300
350
400
7
8
10
6
7
8
10
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3.5
4
4
5
6
7
9.5
Selective limit current
NF400-HEP 100
200
225
250
300
350
400
7
8
10
6
7
8
10
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3.5
4
4
5
6
7
9.5
Selective limit current
NF630-CP 50
500
600
630 Selective limit current
NF630-SP 50
500
600
630 Selective limit current
NF630-SEP 85
300
350
400
500
600
630 Selective limit current
NF630-HEP 100
300
350
400
500
600
630
Icu: Rated breaking capacity
49
Icu(kA)
Type
Rated current
(A)
NF800-CEP NF800-SEP NF1000-SS NF1250-SS
50 85 125 125
400 450 500 600 700 800400 450 500 600 700 800 600 700 800 1000 12001250
NF1600-SS
125
800 1000 1200 1400 1500 1600500 600 700 800 900 1000
Selective limit current
125
150
175
200
225
250
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
50
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
50
6
6
6
6
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
50
Selective limit current
125
150
175
200
225
250
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
50
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
50
6
6
6
6
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
50
250
300
350
400
Selective limit current
7
8
10
6
7
8
10
5
7
8
10
5
5
6
7
4
5
6
6
3.5
4
5
6
10
7
8
10
6
7
8
10
6
7
8
10
5
5
6
7
4
5
6
6
3.5
4
5
6
10
7.5
20
7.5
20
4.5 4.5
4.5
6
6
4.5
4.5
4.5 4.5
4.5 4.5
4.5 4.5
20
250
300
350
400
Selective limit current
10 8
10 7
10
10
6
7
10
10
5
6
7
8
5
6
7
7
10
10 8
10 7
10
10
6
7
10
10
5
6
7
8
5
6
7
7
10
7.5 7.5
7.5
7.5 7.5
7.5 7.5
7.5
20
7.5 7.5
7.5 7.5
7.5
7.5 7.5
7.5
7.5
20
6 6
64.5
6
6
4.5
4.5
6
6
4.5
4.5
6
6
4.5
4.5
6
20
Selective limit current
200
225
250
300
350
400
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
7
8
3.5
4
5
5
6
7
3
3.5
4
5
5
6
3
3
3.5
4
5
5
10
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
7
8
3.5
4
5
5
6
7
3
3.5
4
5
5
6
3
3
3.5
4
5
5
10
10
10
10
10
10
10
10
10
10
10
10
10
20
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
20
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
20
Selective limit current
200
225
250
300
350
400
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
7
8
3.5
4
5
5
6
7
3
3.5
4
5
5
6
3
3
3.5
4
5
6
10
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
7
8
3.5
4
5
5
6
7
3
3.5
4
5
5
6
3
3
3.5
4
5
6
10
10
10
10
10
10
10
10
10
10
10
10
10
20
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
20
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
20
Selective limit current
500
600
630
10 8
10
10
7
8
8
9.6
10 8
10
10
7
8
8
9.6
6
64.5
6
6
4.5
6
6
20
Selective limit current
500
600
630
10
9.6
10
9.6
6
20
Selective limit current
300
350
400
500
600
630
8
10 7
8
10
7
7
8
5
6
7
10
5
5
6
8
10
10
4
5
6
7
8
8
9.6
8
10 7
8
10
7
7
8
5
6
7
10
5
5
6
8
10
10
4
5
6
7
8
8
9.6
10
10
10
10
20
Selective limit current
300
350
400
500
600
630
8
10 7
8
10
7
7
8
5
6
7
10
5
5
6
8
8
10
4
5
6
7
8
8
9.6
8
10 7
8
10
7
7
8
5
6
7
10
5
5
6
8
8
10
4
5
6
7
8
8
9.6
10
10
10
10
20
Branch Breaker
Main Breaker
Type Icu(kA)
NF250-SEP 50
NF250-HEP 100
NF400-CP 50
NF400-SP 85
NF400-SEP 85
NF400-HEP 100
NF630-CP 50
NF630-SP 50
NF630-SEP 85
NF630-HEP 100
Icu: Rated breaking capacity
50
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
440VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP NF400-SEP NF630-SEP
30 50 50 50
Type Icu(kA) 125 150 175 200 225 25030 40 50 60 75 100 300 350 400 500 600 630200 225 250 300 350 400
Selective limit current
NF30-SP 5 3
5
10
15
20
30
4
6
8
3
5
6
10
2.5
3.5
5
7
3
4
6
2.5
3
52.5
3.5
0.8 1.6
3 2.5
3.5 2.5 2.5
Selective limit current
NF50-CP 5 10
15
20
30
40
50
4
6
8
3
5
6
10
2.5
3.5
5
7
10
3
4
6
8
10
2.5
3
5
6
8
2.5
3.5
5
6
0.8 1.6
3
4
5
2.5
3
43
3.5 2.5
3 2.5 2.5
3.5
2.5
3 2.5 2.5
2.5 2.5
Selective limit current
NF50-HP 10 10
15
20
30
40
50
4
6
8
3
5
6
10
2.5
3.5
5
7
10
3
4
6
8
10
2.5
3
5
6
8
2.5
3.5
5
6
0.8 1.6
3
4
5
2.5
3
43
3.5 2.5
3 2.5 2.5
3.5
2.5
3 2.5 2.5
7.5 10
Selective limit current
NF60-CP 560 10 7
1.6 6543.533
3.5 3.5 3 3 2.5
2.5 2.5 2.5
Selective limit current
NF60-HP 10 60 10 7
1.6 6543.533
3.5 3.5 3 3 2.5
7.5 2.5 10
Selective limit current
NF100-CP 10 50
60
75
100
8
10 7
8
10
6
7
8
5
6
7
10
5
5
7
10
4
5
6
8
3.5 5
6
7
10
5
5
7
10
4
5
6
8
3.5
4
5
7
3
3.5
4
6
2.5
3
3.5
5
52.5
3
4
5
2.5
2.5
3.5
5
2.5
3
42.5
3 2.5 2.5
10
Selective limit current
NF100-SP 30
15
20
30
40
50
60
75
100
2.5
3
5
6
8
10
2.5
4
5
7
8
10
2.5
3.5
5
6
7
8
3
4
5
6
7
10
2.5
3
4
5
6
8
2.5
3.5
5
5
7
10
3.5
3
4
5
6
7
10
2.5
3.5
5
5
7
10
2.5
3
4
5
6
8
2.5
3.5
4
5
7
2.5
3
3.5
5
2.5
3
3.5
4
6
5
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
42.5
3 2.52.5
10
Selective limit current
NF100-SP
T/A 30 15 20
20 25
25 40
40 63
63 80
80 100
2.5
3
4
6
10
2.5
3.5
5
8
10
2.5
3
5
7
10
2.5
4
6
8
2.5
3.5
6
7
3
5
6
3.5
2.5
4
6
8
2.5
3.5
6
8
3
5
6
2.5
4
5
2.5
3.5
53
4
5
2.5
3.5
53
3.5 2.5
3.5 2.5 2.5
10
Selective limit current
NF100-HP 50
15
20
30
40
50
60
75
100
2.5
3
5
6
8
10
2.5
4
5
7
8
10
2.5
3.5
5
6
7
8
3
4
5
6
7
10
2.5
3
4
5
6
8
2.5
3.5
5
5
7
10
3.5
3
4
5
6
7
10
3.5
3.5
5
5
7
10
2.5
3
4
5
6
8
2.5
3.5
4
5
7
2.5
3
3.5
5
2.5
3
3.5
4
6
7.5
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
42.5
3 2.52.5
18
Selective limit current
NF100-HP
T/A 50 15 20
20 25
25 40
40 63
63 80
80 100
2.5
3
4
6
10
2.5
3.5
5
8
10
2.5
3
5
7
10
2.5
4
6
8
2.5
3.5
6
7
3
5
6
3.5
2.5
4
6
8
2.5
3.5
6
8
3
5
6
2.5
4
5
2.5
3.5
53
4
7.5
2.5
3.5
53
3.5 2.5
3.5 2.5 2.5
18
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
51
Icu(kA)
Type
Rated current
(A)
NF800-CEP NF800-SEP NF1000-SS NF1250-SS
36 42 85 85
400 450 500 600 700 800400 450 500 600 700 800 600 700 800 1000 12001250
NF1600-SS
85
800 1000 1200 1400 1500 1600500 600 700 800 900 1000
Selective limit current
3
5
10
15
20
30
2.5 2.5 5 5 5
Selective limit current
10
15
20
30
40
50
2.5 2.5 5 5 5
Selective limit current
10
15
20
30
40
50
10 10 10 10 10
Selective limit current
60 2.5 2.5 5 5 5
Selective limit current
60 10 10 10 10 10
50
60
75
100
Selective limit current
3
42.5
3.5 2.5
3 2.5 2.5
10
3
42.5
3.5 2.5
3 2.5 2.5
10 1010 10
Selective limit current
15
20
30
40
50
60
75
100
3
42.5
3.5 2.5
3 2.5 2.5
10
3
42.5
3.5 2.5
3 2.5 2.5
10 22 22 22
Selective limit current
15 20
20 25
25 40
40 63
63 80
80 100
2.5
3.5 2.5
3 2.5
10
2.5
3.5 2.5
3 2.5
10 22 22 22
Selective limit current
15
20
30
40
50
60
75
100
3
42.5
3.5 2.5
3 2.5 2.5
18
3
42.5
3.5 2.5
3 2.5 2.5
18 50 50 50
Selective limit current
15 20
20 25
25 40
40 63
63 80
80 100
2.5
3.5 2.5
3 2.5
18
2.5
3.5 2.5
3 2.5
18 50 50 50
Branch Breaker
Main Breaker
Type Icu(kA)
NF30-SP 5
NF50-CP 5
NF50-HP 10
NF60-CP 5
NF60-HP 10
NF100-CP 10
NF100-SP 30
NF100-SP
T/A 30
NF100-HP 50
NF100-HP
T/A 50
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
52
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION) 440VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP NF400-SEP NF630-SEP
30 50 50 50
Type Icu(kA)
125 150 175 200 225 25030 40 50 60 75 100 300 350 400 500 600 630200 225 250 300 350 400
Selective limit current
NF100-SEP 25 30
40
50
60
75
100
2.5
3.5
5
6
7
10
3
3.5
5
6
8
2.5
3
3.5
5
6
2.5
3
3.5
4
6
2.5
3
3.5
5
2.5
3.5
5
3.5
2.5
3
3.5
4
6
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
3.5 2.5
33
5
2.5
3
3.5 2.5
3 3 2.5
10
Selective limit current
NF100-HEP 50 30
40
50
60
75
100
2.5
3.5
5
6
7
10
3
3.5
5
6
8
2.5
3
3.5
5
6
2.5
3
3.5
4
6
2.5
3
3.5
5
2.5
3.5
5
3.5
2.5
3
3.5
4
6
2.5
3
4
5
2.5
2.5
3.5
5
2.5
3
3.5 2.5
33
7.5
2.5
3
3.5 2.5
3 3 2.5
18
Selective limit current
NF160-SP 25 125
150
160
10 10 8
10
3.5 6
8
8
6
7
7
5
6
6
4
5
5
3
4
4
3
3.5
4
10
Selective limit current
NF160-SP
T/A 25 100 125
125 160 10
10 10
10 8
87
7
3.5 5
55
54
43
32.5
2.5 2.5
2.5
10
Selective limit current
NF160-HP 50 125
150
160
10 10 8
10
3.5 6
8
8
6
7
7
5
6
6
4
5
5
3
4
4
3
3.5
4
10
Icu: Rated breaking capacity
Selective limit current
NF160-HP
T/A 50 100 125
125 160 10
10 10
10 8
87
7
3.5 5
55
54
43
32.5
2.5 2.5
2.5
10
Selective limit current
NF250-CP 15 125
150
175
200
225
250
6
8
10
10
6
7
8
10
10
5
6
7
8
8
10
4
5
5
6
7
8
3
4
5
5
6
6
3
3.5
4
5
6
6
7.5
Selective limit current
NF250-CP
T/A 15 100 125
125 160
150 200
200 250
5
5
8
10
5
5
7
8
4
4
6
7
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
4
7.5
Selective limit current
NF250-SP 25 125
150
175
200
225
250
6
8
10
10
6
7
8
10
10
5
6
7
8
8
10
4
5
5
6
7
8
3
4
5
5
6
6
3
3.5
4
5
6
6
10
Selective limit current
NF250-SP
T/A 25 100 125
125 160
150 200
200 250
5
5
8
10
5
5
7
8
4
4
6
7
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
4
10
Selective limit current
NF250-HP 50 125
150
175
200
225
250
6
8
10
10
6
7
8
10
10
5
6
7
8
8
10
4
5
5
6
7
8
3
4
5
5
6
6
3
3.5
4
5
6
6
10
Selective limit current
NF250-HP
T/A 50 100 125
125 160
150 200
200 250
5
5
8
10
5
5
7
8
4
4
6
7
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
4
10
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
53
Icu(kA)
Type
Rated current
(A)
NF800-CEP NF800-SEP NF1000-SS NF1250-SS
36 42 85 85
400 450 500 600 700 800400 450 500 600 700 800 600 700 800 1000 12001250
NF1600-SS
85
800 1000 1200 1400 1500 1600500 600 700 800 900 1000
Selective limit current
30
40
50
60
75
100
3 2.5 2.5
10
3 2.5 2.5
10 22 22 22
Selective limit current
30
40
50
60
75
100
3 2.5 2.5
18
3 2.5 2.5
18 50 50 50
Selective limit current
125
150
160
5
6
6
4
5
6
4
5
5
3
4
4
3
3.5
3.5
2.5
3
3
10
5
6
6
4
5
5
4
5
5
3
4
4
3
3.5
3.5
2.5
3
3
10
7.5
7.5
22
4.5
4.5
2222
Selective limit current
100 125
125 160
4
44
43
32.5
2.5 2.5
2.5
10
4
44
43
32.5
2.5 2.5
2.5
10 22 22 22
Selective limit current
125
150
160
5
6
6
4
5
6
4
5
5
3.5
4
4
3
3.5
3.5
2.5
3
3
10
5
6
6
4
5
6
4
5
5
3.5
4
4
3
3.5
3.5
2.5
3
3
10
7.5
7.5
22
4.5
4.5
2222
Selective limit current
100 125
125 160
4
43.5
3.5 3
32.5
2.5 2.5
2.5
10
4
43.5
3.5 3
32.5
2.5 2.5
2.5
10 22 22 22
Selective limit current
125
150
175
200
225
250
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
7.5
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
7.5
7.5 7.5 7.5
7.5 7.5
15
7.5 7.5
7.5 7.5
15
4.5
4.5
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5 4.5
15
100 125
125 160
150 200
200 250
Selective limit current
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
7.5
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
7.5 1515
4.5
4.5 4.5
15
Selective limit current
125
150
175
200
225
250
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3.5
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3.5
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
7.5 7.5 7.5
7.5 7.5
22
7.5 7.5
7.5 7.5
22
4.5
4.5
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5 4.5
22
100 125
125 160
150 200
200 250
Selective limit current
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10 2222
4.5
4.5 4.5
22
Selective limit current
125
150
175
200
225
250
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3.5
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
5
6
7
8
8
7
4
5
6
7
8
6
4
5
5
6
7
6
3.5
4
5
5
6
5
3
3.5
4
5
5
4
2.5
3
3.5
4
4
3.5
10
7.5 7.5 7.5
7.5 7.5
22
7.5 7.5
7.5 7.5
22
4.5
4.5
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5 4.5
22
100 125
125 160
150 200
200 250
Selective limit current
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10
4
4
6
7
3.5
3.5
5
6
3
3
5
6
2.5
2.5
4
5
2.5
2.5
3.5
43
3.5
10 2222
4.5
4.5 4.5
22
Branch Breaker
Main Breaker
Type Icu(kA)
NF100-SEP 25
NF100-HEP 50
NF160-SP 25
NF160-SP
T/A 25
NF160-HP 50
NF160-HP
T/A 50
NF250-CP 15
NF250-CP
T/A 15
NF250-SP 25
NF250-SP
T/A 25
NF250-HP 50
NF250-HP
T/A 50
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
54
Branch Breaker Icu(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
440VAC (Sym. kA)
Rated current
(A)
NF100-SEP NF250-SEP NF400-SEP NF630-SEP
50 50 85 85
Type Icu(kA)
125 150 175 200 225 25030 40 50 60 75 100 300 350 400 500 600 630200 225 250 300 350 400
Selective limit current
NF250-SEP 25
125
150
175
200
225
250
5
6
6
7
8
10
4
5
6
6
7
8
3.5
4
5
6
6
7
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
2.5
3
3.5
4
5
10
Selective limit current
NF250-HEP 50
125
150
175
200
225
250
5
6
6
7
8
10
4
5
6
6
7
8
3.5
4
5
6
6
7
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
2.5
3
3.5
4
5
10
Selective limit current
NF400-CP 25
250
300
350
400
10 8
10 7
8
10
6
7
8
10
5
6
6
7
5
5
6
7
9.5
Selective limit current
NF400-SP 42
250
300
350
400
10 8
10
10
6
8
10
10
6
7
8
10
9.5
Selective limit current
NF400-SEP 42
200
225
250
300
350
400
7
8
10
6
7
8
10
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3.5
4
5
5
6
7
9.5
Selective limit current
NF400-HEP 65
200
225
250
300
350
400
7
8
10
6
7
8
10
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3.5
4
5
5
6
7
9.5
Selective limit current
NF630-CP 36
500
600
630 Selective limit current
NF630-SP 42
500
600
630 Selective limit current
NF630-SEP 42
300
350
400
500
600
630 Selective limit current
NF630-HEP 65
300
350
400
500
600
630
Icu: Rated breaking capacity
55
Icu(kA)
Type
Rated current
(A)
NF800-CEP NF800-SEP NF1000-SS NF1250-SS
36 42 85 85
400 450 500 600 700 800400 450 500 600 700 800 600 700 800 1000 12001250
NF1600-SS
85
800 1000 1200 1400 1500 1600500 600 700 800 900 1000
Selective limit current
125
150
175
200
225
250
4
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
4
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
22
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
22
6
6
6
6
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
22
Selective limit current
125
150
175
200
225
250
4
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
4
4
5
6
6
7
3
3.5
4
5
6
6
3
3.5
4
5
5
6
2.5
3
3
3.5
4
5
2.5
3
3
3.5
4
2.5
3
3
3.5
10
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
22
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
22
6
6
6
6
6
6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
22
250
300
350
400
Selective limit current
7
8
10
6
7
8
10
6
7
8
10
5
6
6
7
4
5
6
6
3.5
4
5
6
10
7
8
10
6
7
8
10
6
7
8
10
5
6
6
7
4
5
6
6
3.5
4
5
6
10
7.5
20
7.5
20
4.5 4.5
4.5
6
6
4.5
4.5
4.5 4.5
4.5 4.5
4.5 4.5
20
250
300
350
400
Selective limit current
10 8
10 8
10
10
6
8
10
10
6
7
8
10
5
6
7
8
10
10 8
10 8
10
10
6
8
10
10
6
7
8
10
5
6
7
8
10
7.5 7.5
7.5
7.5 7.5
7.5 7.5
7.5
20
7.5 7.5
7.5 7.5
7.5
7.5
7.5
20
66
64.5
6
6
4.5
4.5
6
6
4.5
4.5
4.5
6
4.5
4.5
6
20
Selective limit current
200
225
250
300
350
400
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3
3.5
4
5
6
10
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3
3.5
4
5
6
10
10
10
10
10
10
10
10
10
10
10
10
10
20
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
20
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
20
Selective limit current
200
225
250
300
350
400
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3
3.5
4
5
6
10
6
6
7
8
10
5
6
6
7
8
10
5
5
6
7
8
10
3.5
4
5
6
6
7
3
3.5
4
5
6
6
3
3
3.5
4
5
6
10
10
10
10
10
10
10
10
10
10
10
10
10
20
10
10
10
10
10
10
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
20
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
20
Selective limit current
500
600
630
10 8
10
10
7
8
8
10
10 8
10
10
7
8
8
10
6
64.5
6
6
4.5
6
6
20
Selective limit current
500
600
630
10
10
10
10
6
20
Selective limit current
300
350
400
500
600
630
8
10 7
8
10
7
8
10
6
6
7
10
5
6
6
8
10
10
4
5
6
7
8
8
10
8
10 7
8
10
7
8
10
6
6
7
10
5
6
6
8
10
10
4
5
6
7
8
8
10
10
10
10
10
20
Selective limit current
300
350
400
500
600
630
8
10 7
8
10
7
8
10
6
6
7
10
5
6
6
8
10
10
4
5
6
7
8
8
10
8
10 7
8
10
7
8
10
6
6
7
10
5
6
6
8
10
10
4
5
6
7
8
8
10
10
10
10
10
20
Branch Breaker
Main Breaker
Type Icu(kA)
NF250-SEP 25
NF250-HEP 50
NF400-CP 25
NF400-SP 42
NF400-SEP 42
NF400-HEP 65
NF630-CP 36
NF630-SP 42
NF630-SEP 42
NF630-HEP 65
Icu: Rated breaking capacity
56
Branch Breaker Ics(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
230VAC (Sym. kA)
Rated current
(A)
AE630-SS AE1000-SS AE1250-SS AE1600-SS
65 65 65 65
Type Icu(kA)
500 600 700 800 900 1000315 378 441 504 567 630 800 960 1120 1280 1440 1600625 750 875 1000 11251250
In=500 .... 7.5(25) 630 .... 15(25) 800 .... 25 1000 .... 25 1250 .... 25 1600 .... 25
Selective limit current
NF100-CP 25
60
75
100
4
6
8
4
4
6
3
4
6
3
3
4
3
3
43
4
3
3
43
43
333 3
433 3
In=500 .... 7.5(50) 630 .... 16(50) 800 .... 24(50) 1000 .... 45(50) 1250 .... 50 1600 .... 50
Selective limit current
NF100-SP 50
60
75
100
4
6
8
4
4
6
3
4
6
3
3
4
3
3
43
4
3
3
43
43
333 3
433 3
Selective limit current
In=500 .... 7.5(50) 630 .... 16(50) 800 .... 24(50) 1000 .... 45(50) 1250 .... 50 1600 .... 50
NF100-SP
T/A 50
63 80
80 100 6
64
63
43
43
33
33
43
33 3
33
In=500 .... 13(65) 630 .... 24(65) 800 .... 43(65) 1000 .... 65 1250 .... 65 1600 .... 65
Selective limit current
NF100-HP 100
60
75
100
4
6
8
4
4
6
3
4
6
3
3
4
3
3
43
4
3
3
43
43
333 3
433 3
Selective limit current
In=500 .... 13(65) 630 .... 24(65) 800 .... 43(65) 1000 .... 65 1250 .... 65 1600 .... 65
NF100-HP
T/A 100
63 80
80 100 6
64
63
43
43
33
33
43
33 3
33
In=500 .... 7.5(50) 630 .... 16(50) 800 .... 24(50) 1000 .... 45(50) 1250 .... 50 1600 .... 50
Selective limit current
NF100-SEP 50
60
75
100
3
3
43
43
333333
In=500 .... 13(65) 630 .... 24(65) 800 .... 43(65) 1000 .... 65 1250 .... 65 1600 .... 65
Selective limit current
NF100-HEP 100
60
75
100
3
3
43
43
333333
In=500 .... 7.5(50) 630 .... 15(50) 800 .... 19(50) 1000 .... 24(50) 1250 .... 30(50) 1600 .... 42(50)
Selective limit current
NF160-SP 50
125
150
160
8
10
10
6
8
8
6
6
8
6
6
6
4
6
6
4
6
6
6
6
6
4
6
6
4
4
6
3
4
4
3
3
4
3
3
3
4
6
6
3
4
4
3
4
4
3
3
33
33
3
3
4
4
3
3
33
33
3
Selective limit current
In=500 .... 7.5(50) 630 .... 15(50) 800 .... 19(50) 1000 .... 24(50) 1250 .... 30(50) 1600 .... 42(50)
NF160-SP
T/A 50
100 125
125 160 6
66
66
64
44
43
34
43
33
33
33
33
33
33
3
In=500 .... 7.5(65) 630 .... (65) 800 .... 12(65) 1000 .... 25(65) 1250 .... 40(65) 1600 .... 65
Selective limit current
NF160-HP 100
125
150
160
8
10
10
6
8
8
6
6
8
6
6
6
4
6
6
4
6
6
6
6
6
4
6
6
4
4
6
3
4
4
3
3
4
3
3
3
4
6
6
3
4
4
3
4
4
3
3
33
33
3
3
4
4
3
3
33
33
3
Selective limit current
In=500 .... 7.5(65) 630 .... 9.4(65) 800 .... 1(65) 1000 .... 25(65) 1250 .... 40(65) 1600 .... 65
NF160-HP
T/A 100
100 125
125 160 6
66
66
64
44
43
34
43
33
33
33
33
33
33
3
Selective limit current
In=500 .... 7.5(30) 630 .... 9.4(30) 800 .... 12(30) 1000 .... 22.5(30) 1250 .... 30 1600 .... 30
NF250-CP 30
125
150
175
200
225
250
8
10 6
8
10
10
6
6
8
8
10
8
6
6
8
8
8
8
4
6
6
8
8
6
4
6
6
6
8
6
6
6
8
8
8
8
4
6
6
6
8
6
4
4
6
6
6
6
3
4
4
6
6
6
3
3
4
4
6
4
3
3
4
4
4
4
4
6
6
6
8
6
3
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
4
4
3
3
4
4
3
3
3
3
4
3
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
3
3
3
3
4
3
3
3
3
3
3
3
Selective limit current
In=500 .... 7.5(30) 630 .... 9.4(30) 800 .... 12(30) 1000 .... 22.5(30) 1250 .... 30 1600 .... 30
NF250-CP
T/A 30
100 125
125 160
150 200
200 250
4
4
6
8
3
3
6
6
3
3
4
6
3
3
4
63
43
4
3
3
6
6
3
3
4
6
3
3
4
43
43
33
3
3
3
4
43
43
33
33
6
6
10
6
6
8
10
6
6
8
8
4
4
6
8
4
4
6
6
3
3
6
6
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
57
Ics(kA)
Type
Rated current
(A)
AE2000-SS AE2500-SS AE3200-SS
AE4000-SSC
85 85 85 85
1250 1500 1750 2000 2250 250010001200 1400 1600 1800 2000 3200 3600 40001600 1920 2240 2560 28803200
Selective limit current
In=1000 .... 25 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
60
75
100 Selective limit current
In=1000 .... 45(50) 1600 .... 50 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
60
75
100 Selective limit current
In=1000 .... 45(50) 1600 .... 50 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
63 80
80 100 Selective limit current
In=1000 .... 85 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
60
75
100 Selective limit current
In=1000 .... 85 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
63 80
80 100 Selective limit current
In=1000 .... 45(50) 1600 .... 50 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
60
75
100 Selective limit current
In=1000 .... 85 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
60
75
100 Selective limit current
In=1000 .... 24(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
125
150
160
3
3
33
33 3
3Selective limit current
In=1000 .... 24(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
100 125
125 160 Selective limit current
In=1000 .... 25(65) 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
125
150
160
3
3
33
33 3
3Selective limit current
In=1000 .... 25(65) 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
100 125
125 160 Selective limit current
In=1000 .... 30 1600 .... 30 2000 .... 30 2500 .... 30 3200 .... 30 4000 .... 30
125
150
175
200
225
250
3
3
4
4
4
4
3
3
3
4
3
3
3
3
3
3
33
3
3
3
4
3
3
3
3
3
3
33
33
100 125
125 160
150 200
200 250
Selective limit current
In=1000 .... 30 1600 .... 30 2000 .... 30 2500 .... 30 3200 .... 30 4000 .... 30
3
43
33 3
33
Branch Breaker
Main Breaker
Type Icu(kA)
NF100-CP 25
NF100-SP 50
NF100-SP
T/A 50
NF100-HP 100
NF100-HP
T/A 100
NF100-SEP 50
NF100-HEP 100
NF160-SP 50
NF160-SP
T/A 50
NF160-HP 100
NF160-HP
T/A 100
NF250-CP 30
NF250-CP
T/A 30
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
58
Branch Breaker Ics(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION) 230VAC (Sym. kA)
Rated current
(A)
AE630-SS AE1000-SS AE1250-SS AE1600-SS
65 65 65 65
Type Icu(kA)
500 600 700 800 900 1000315 378 441 504 567 630 800 960 1120 1280 1440 1600625 750 875 1000 11251250
Selective limit current
In=500 .... 7.5(50) 630 .... 15(50) 800 .... 19(50) 1000 .... 24(50) 1250 .... 30(50) 1600 .... 42(50)
NF250-SP 50 125
150
175
200
225
250
8
10 6
8
10
10
6
6
8
8
10
8
6
6
8
8
8
8
4
6
6
8
8
6
4
6
6
6
8
6
6
6
8
8
8
8
4
6
6
6
8
6
4
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
4
4
4
6
6
6
8
6
3
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
4
4
3
3
4
4
3
3
3
3
4
3
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
3
3
3
3
4
3
3
3
3
3
3
3
Selective limit current
In=500 .... 7.5(50) 630
....
15(50) 800
....
19(50) 1000
....
24(50) 1250
....
30(50) 1600
....
42(50)
NF250-SP
T/A 50 100 125
125 160
150 200
200 250
4
4
6
8
3
3
6
6
3
3
4
6
3
3
4
43
43
4
3
3
6
6
3
3
4
6
3
3
4
43
43
33
3
3
3
4
43
43
33
33
6
6
10
6
6
8
10
6
6
8
8
4
4
6
8
4
4
6
6
3
3
6
6Selective limit current
In=500 .... 7.5(65) 630 .... 9.4(65) 800 .... 12(65) 1000 .... 25(65) 1250 .... 40(65) 1600 .... 65
NF250-HP 100 125
150
175
200
225
250
8
10 6
8
10
10
6
6
8
8
10
8
6
6
8
8
8
8
4
6
6
8
8
6
4
6
6
6
8
6
6
6
8
8
8
8
4
6
6
6
8
6
4
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
4
4
4
6
6
6
8
6
3
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
4
4
3
3
4
4
3
3
3
3
4
3
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
3
3
3
3
4
3
3
3
3
3
3
3
Selective limit current
In=500 .... 7.5(65) 630
....
9.4(65) 800
....
12(65) 1000
....
25(65) 1250
....
40(65) 1600
....
65
NF250-HP
T/A 100 100 125
125 160
150 200
200 250
4
4
6
8
3
3
6
6
3
3
4
6
3
3
4
43
43
4
3
3
6
6
3
3
4
4
3
3
4
43
43
33
3
3
3
4
43
43
33
33
6
6
10
6
6
8
10
6
6
8
8
4
4
6
8
4
4
6
6
3
3
6
6Selective limit current
In=500 .... 7.5(50) 630 .... 15(50) 800 .... 19(50) 1000 .... 24(50) 1250 .... 30(50) 1600 .... 42(50)
NF250-SEP 50 125
150
175
200
225
250
6
6
8
8
10
10
6
6
6
8
8
10
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
4
6
3
3
4
4
4
3
3
3
4
4
3
3
3
4
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
3
3
3
4
3
3
33
3
3
3
4
4
4
3
3
3
4
3
3
33
33
Selective limit current
In=500 .... 7.5(65) 630 .... 9.4(65) 800 .... 12(65) 1000 .... 25(65) 1250 .... 40(65) 1600 .... 65
NF250-HEP 100 125
150
175
200
225
250
6
6
8
8
10
10
6
6
6
8
8
10
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
4
6
3
3
4
4
4
3
3
3
4
4
3
3
3
4
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
3
3
3
4
3
3
33
3
3
3
4
4
4
3
3
3
4
3
3
33
33
Selective limit current
In=500 .... – 630 .... 9.4(50) 800 .... 12(50) 1000 .... 15(50) 1250 .... 20(50) 1600 .... 30(50)
NF400-CP 50 250
300
350
400
66
64
6
6
4
6
6
6
4
4
6
6
66
64
6
6
4
4
6
6
3
4
4
6
3
4
4
6
4
6
6
4
4
6
6
3
4
4
6
3
3
4
4
3
3
4
4
3
3
4
66
Selective limit current
In=500 .... – 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 20(65) 1600 .... 30(65)
NF400-SP 85 250
300
350
400
88
88
8
8
6
6
8
6
6
8
8
86
86
8
8
6
6
8
8
4
6
6
8
4
6
6
6
8
8
8
6
6
8
8
4
6
6
8
4
6
6
8
3
4
6
6
3
4
4
6
88
Selective limit current
In=500 .... – 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 20(65) 1600 .... 30(65)
NF400-SEP 85 200
225
250
300
350
400
6
6
6
8
8
10
4
6
6
6
8
8
6
6
6
8
8
10
4
4
6
6
8
8
4
4
4
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
4
4
4
6
6
8
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
3
3
3
4
3
3
4
Selective limit current
In=500 .... – 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 20(65) 1600 .... 30(65)
NF400-HEP 100 200
225
250
300
350
400
6
6
6
8
8
10
4
6
6
6
8
8
6
6
6
8
8
10
4
4
6
6
8
8
4
4
4
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
4
4
4
6
6
8
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
3
3
3
4
3
3
4
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
59
Ics(kA)
Type
Rated current
(A)
AE2000-SS AE2500-SS AE3200-SS
AE4000-SSC
85 85 85 85
1250 1500 1750 2000 2250250010001200 1400 1600 1800 2000 3200 3600 40001600 1920 2240 2560 28803200
Selective limit current
In=1000 .... 24(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
125
150
175
200
225
250
3
3
4
4
4
4
3
3
3
4
3
3
3
3
3
3
33
3
3
3
4
3
3
3
3
3
3
33
33
100 125
125 160
150 200
200 250
Selective limit current
In=1000 .... 24(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
3
43
33 3
33
Selective limit current
In=1000 .... 25(65) 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
125
150
175
200
225
250
3
3
4
4
4
4
3
3
3
4
3
3
3
3
3
3
33
3
3
3
4
3
3
3
3
3
3
33
33
100 125
125 160
150 200
200 250
Selective limit current
In=1000 .... 25(65) 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
3
43
33 3
33
Selective limit current
In=1000 .... 24(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
125
150
175
200
225
250
3
3
3
4
3
3
33 3
33
Selective limit current
In=1000 .... 25(65) 1600 .... 85 2000 .... 85 2500 .... 85 3200 .... 85 4000 .... 85
125
150
175
200
225
250
3
3
3
4
3
3
33 3
33
250
300
350
400
Selective limit current
In=1000 .... 15(50) 1600 .... 30(50) 2000 .... 48(50) 2500 .... 50 3200 .... 50 4000 .... 50
4
4
6
6
3
4
4
6
3
3
4
4
3
3
4
3
3
33
3
3
4
4
6
3
3
3
4
3
3
33
333
3
3
43
33
250
300
350
400
Selective limit current
In=1000 .... 15(65) 1600 .... 30(65) 2000 .... 48(65) 2500 .... 70 3200 .... 85 4000 .... 85
6
6
8
8
4
6
6
6
4
4
6
6
3
4
4
6
3
3
4
4
3
3
4
4
4
6
6
6
3
4
4
6
3
4
4
6
3
3
4
4
3
3
4
3
3
3
3
4
4
6
3
4
4
3
3
43
33
333
Selective limit current
In=1000 .... 15(65) 1600 .... 30(65) 2000 .... 48(65) 2500 .... 70 3200 .... 85 4000 .... 85
200
225
250
300
350
400
3
3
4
4
6
6
3
3
3
4
4
6
3
3
4
4
3
3
4
3
3
33
3
3
3
3
4
4
3
3
3
4
3
3
33
33
3
3
43
33
Selective limit current
In=1000 .... 15(65) 1600 .... 30(65) 2000 .... 48(65) 2500 .... 70 3200 .... 85 4000 .... 85
200
225
250
300
350
400
3
3
4
4
6
6
3
3
3
4
4
6
3
3
4
4
3
3
4
3
3
33
3
3
3
3
4
4
3
3
3
4
3
3
33
33
3
3
43
33
Branch Breaker
Main Breaker
Type Icu(kA)
NF250-SP 50
NF250-SP
T/A 50
NF250-HP 100
NF250-HP
T/A 100
NF250-SEP 50
NF250-HEP 100
NF400-CP 50
NF400-SP 85
NF400-SEP 85
NF400-HEP 100
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
60
Branch Breaker Ics(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION) 230VAC (Sym. kA)
Rated current
(A)
AE630-SS AE1000-SS AE1250-SS AE1600-SS
65 65 65 65
Type Icu(kA) 500 600 700 800 900 1000315 378 441 504 567 630 800 960 1120 12801440 1600625 750 875 1000 11251250
In=500 .... – 630 .... – 800 .... – 1000 .... – 1250 .... 18.7(50) 1600 .... 24(50)
Selective limit current
NF630-CP 50 500
600
630
66
866
66
6
6
4
6
6
In=500 .... – 630 .... – 800 .... – 1000 .... – 1250 .... 18.7(50) 1600 .... 24(50)
Selective limit current
NF630-SP 50 500
600
630
88 1088
8
8
6
8
8
Selective limit current
In=500 .... – 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF630-SEP 85 300
350
400
500
600
630
88
86
8
8
8
8
10
6
8
8
6
6
8
10
6
6
6
10
10
4
6
6
8
8
8
6
8
8
6
6
8
6
6
6
8
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
8
6
6
8
10
6
6
6
10
10
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
6
6
6
4
4
4
4
6
6
Selective limit current
In=500 .... – 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF630-HEP 100 300
350
400
500
600
630
88
86
8
8
8
8
10
6
8
8
6
6
8
10
6
6
6
10
10
4
6
6
8
8
8
6
8
8
6
6
8
6
6
6
8
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
8
6
6
8
10
6
6
6
10
10
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
6
6
6
4
4
4
4
6
6
Selective limit current
In=500 .... – 630 .... – 800 .... 12(50) 1000 .... 15(50) 1250 .... 18.7(50) 1600 .... 24(50)
NF800-CEP 50 400
450
500
600
700
800
88
8
8
6
8
8
6
6
8
8
66
86
8
8
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
8
8
8
6
8
8
8
6
6
6
8
8
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
8
Selective limit current
In=500 .... – 630 .... – 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF800-SEP 85 400
450
500
600
700
800
88
8
8
6
8
8
6
6
8
8
66
86
8
8
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
8
8
8
6
8
8
8
6
6
6
8
8
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
8
Selective limit current
In=500 .... – 630 .... – 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF800-HEP 100 400
450
500
600
700
800
88
8
8
6
8
8
6
6
8
8
66
86
8
8
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
8
8
8
6
8
8
8
6
6
6
8
8
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
8
Icu: Rated breaking capacity
61
Ics(kA)
Type
Rated current
(A)
AE2000-SS AE2500-SS AE3200-SS
AE4000-SSC
85 85 85 85
1250 1500 1750 2000 2250 250010001200 1400 1600 1800 2000 3200 3600 400016001920 2240 2560 28803200
Selective limit current
In=1000 .... – 1600 .... 24(50) 2000 .... 30(50) 2500 .... 40(50) 3200 .... 50 4000 .... 50
500
600
630
66
6
6
4
6
6
4
6
6
4
4
6
6
86
6
6
4
6
6
4
4
6
4
4
4
4
4
4
4
6
6
4
4
6
4
4
4
4
4
4
4
4
44
44
44
44
Selective limit current
In=1000 .... – 1600 .... 24(50) 2000 .... 30(50) 2500 .... 40(50) 3200 .... 50 4000 .... 50
500
600
630
88
8
10
6
8
8
6
6
8
6
6
6
86
8
8
6
8
8
6
6
6
4
6
6
4
6
6
6
8
8
6
6
6
4
6
6
4
6
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Selective limit current
In=1000 .... 15(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 40(65) 3200 .... 60(65) 4000 .... 85
300
350
400
500
600
630
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
6
6
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
44
44
44
4
Selective limit current
In=1000 .... 15(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 40(65) 3200 .... 60(65) 4000 .... 85
300
350
400
500
600
630
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
6
6
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
44
44
44
4
Selective limit current
In=1000 .... 15(50) 1600 .... 24(50) 2000 .... 30(50) 2500 .... 40(50) 3200 .... 50 4000 .... 50
400
450
500
600
700
800
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Selective limit current
In=1000 .... 15(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 40(65) 3200 .... 60(65) 4000 .... 85
400
450
500
600
700
800
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Selective limit current
In=1000 .... 15(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 40(65) 3200 .... 60(65) 4000 .... 85
400
450
500
600
700
800
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
6
6
6
6
8
4
4
6
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Branch Breaker
Main Breaker
Type Icu(kA)
NF630-CP 50
NF630-SP 50
NF630-SEP 85
NF630-HEP 100
NF800-CEP 50
NF800-SEP 85
NF800-HEP 100
Icu: Rated breaking capacity
62
Branch Breaker Ics(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
440VAC (Sym. kA)
Rated current
(A)
AE630-SS AE1000-SS AE1250-SS AE1600-SS
65 65 65 65
Type Icu(kA)
500 600 700 800 900 1000315 378 441 504 567 630 800 960 1120 1280 1440 1600625 750 875 1000 11251250
In=500 .... 7.5(10) 630 .... 9.8(10) 800 .... 10 1000 .... 10 1250 .... 10 1600 .... 10
Selective limit current
NF100-CP 10
60
75
100
4
6
8
4
4
6
3
4
6
3
3
4
3
3
43
4
3
3
43
43
333 3
433 3
In=500 .... 7(30) 630 .... 9(30) 800 .... 14.5(30) 1000 .... 20(30) 1250 .... 25(30) 1600 .... 30
Selective limit current
NF100-SP 30
60
75
100
4
6
8
4
4
6
3
4
6
3
3
4
3
3
43
4
3
3
43
43
333 3
433 3
Selective limit current
In=500 .... 7(30) 630 .... 9(30) 800 .... 14.5(30) 1000 .... 20(30) 1250 .... 25(30) 1600 .... 30
NF100-SP
T/A 30
63 80
80 100 6
64
63
43
43
33
33
43
33 3
33
In=500 .... 11.2(50) 630 .... 16(50) 800 .... 30(50) 1000 .... 50 1250 .... 50 1600 .... 50
Selective limit current
NF100-HP 50
60
75
100
4
6
8
4
4
6
3
4
6
3
3
4
3
3
43
4
3
3
43
43
333 3
433 3
Selective limit current
In=500 .... 11.2(50) 630 .... 16(50) 800 .... 30(50) 1000 .... 50 1250 .... 50 1600 .... 50
NF100-HP
T/A 50
63 80
80 100 6
64
63
43
43
33
33
43
33 3
33
In=500 .... 7(25) 630 .... 9(25) 800 .... 14.5(25) 1000 .... 20(25) 1250 .... 25 1600 .... 25
Selective limit current
NF100-SEP 25
60
75
100
3
3
43
43
333333
In=500 .... 11.2(50) 630 .... 16(50) 800 .... 30(50) 1000 .... 50 1250 .... 50 1600 .... 50
Selective limit current
NF100-HEP 50
60
75
100
3
3
43
43
333333
In=500 .... 6(25) 630 .... 7(25) 800 .... 11(25) 1000 .... 14(25) 1250 .... 19(25) 1600 .... 25
Selective limit current
NF160-SP 25
125
150
160
8
10
10
6
8
8
6
6
8
6
6
6
4
6
6
4
6
6
6
6
6
4
6
6
4
4
6
3
4
4
3
3
4
3
3
3
4
6
6
3
4
4
3
4
4
3
3
33
33
3
3
4
4
3
3
33
33
3
Selective limit current
In=500 .... 6(25) 630 .... 7(25) 800 .... 11(25) 1000 .... 14(25) 1250 .... 19(25) 1600 .... 25
NF160-SP
T/A 25
100 125
125 160 6
66
66
64
44
43
34
43
33
33
33
33
33
33
3
In=500 .... 7(50) 630 .... 9(50) 800 .... 12(50) 1000 .... 15(50) 1250 .... 25(50) 1600 .... 42(50)
Selective limit current
NF160-HP 50
125
150
160
8
10
10
6
8
8
6
6
8
6
6
6
4
6
6
4
6
6
6
6
6
4
6
6
4
4
6
3
4
4
3
3
4
3
3
3
4
6
6
3
4
4
3
4
4
3
3
33
33
3
3
4
4
3
3
33
33
3
Selective limit current
In=500 .... 7(50) 630 .... 9(50) 800 .... 12(50) 1000 .... 15(50) 1250 .... 25(50) 1600 .... 42(50)
NF160-HP
T/A 50
100 125
125 160 6
66
66
64
44
43
34
43
33
33
33
33
33
33
3
Selective limit current
In=500 .... 7.5(15) 630 .... 9.4(15) 800 .... 12(15) 1000 .... 15 1250 .... 15 1600 .... 15
NC250-CP 15
125
150
175
200
225
250
8
10 6
8
10
10
6
6
8
8
10
8
6
6
8
8
8
8
4
6
6
8
8
6
4
6
6
6
8
6
6
6
8
8
8
8
4
6
6
6
8
6
4
4
6
6
6
6
3
4
4
6
6
6
3
3
4
4
6
4
3
3
4
4
4
4
4
6
6
6
8
6
3
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
4
4
3
3
4
4
3
3
3
3
4
3
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
3
3
3
3
4
3
3
3
3
3
3
3
Selective limit current
In=500 .... 7.5(15) 630 .... 9.4(15) 800 .... 12(15) 1000 .... 15 1250 .... 15 1600 .... 15
NF250-CP
T/A 15
100 125
125 160
150 200
200 250
4
4
6
8
3
3
4
6
3
3
4
6
3
3
4
63
43
4
3
3
6
6
3
3
4
6
3
3
4
43
43
33
3
3
3
4
43
43
33
33
6
6
10
6
6
8
10
6
6
8
8
4
4
6
8
4
4
6
6
3
3
6
6
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
63
Ics(kA)
Type
Rated current
(A)
AE2000-SS AE2500-SS AE3200-SS
AE4000-SSC
85 85 85 85
1250 1500 1750 2000 2250 250010001200 1400 1600 1800 2000 3200 3600 40001600 1920 2240 2560 28803200
Selective limit current
In=1000 .... 10 1600 .... 10 2000 .... 10 2500 .... 10 3200 .... 10 4000 .... 10
60
75
100 Selective limit current
In=1000 .... 20(30) 1600 .... 30 2000 .... 30 2500 .... 30 3200 .... 30 4000 .... 30
60
75
100 Selective limit current
In=1000 .... 20(30) 1600 .... 30 2000 .... 30 2500 .... 30 3200 .... 30 4000 .... 30
63 80
80 100 Selective limit current
In=1000 .... 50 1600 .... 50 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
60
75
100 Selective limit current
In=1000 .... 50 1600 .... 50 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
63 80
80 100 Selective limit current
In=1000 .... 20(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
60
75
100 Selective limit current
In=1000 .... 50 1600 .... 50 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
60
75
100 Selective limit current
In=1000 .... 14(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
125
150
160
3
3
33
33 3
3Selective limit current
In=1000 .... 14(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
100 125
125 160 Selective limit current
In=1000 .... 15(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
125
150
160
3
3
33
33 3
3Selective limit current
In=1000 .... 15(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
100 125
125 160 Selective limit current
In=1000 .... 15 1600 .... 15 2000 .... 15 2500 .... 15 3200 .... 15 4000 .... 15
125
150
175
200
225
250
3
3
4
4
4
4
3
3
3
4
3
3
3
3
3
3
33
3
3
3
4
3
3
3
3
3
3
33
33
100 125
125 160
150 200
200 250
Selective limit current
In=1000 .... 15 1600 .... 15 2000 .... 15 2500 .... 15 3200 .... 15 4000 .... 15
3
43
33 3
33
Branch Breaker
Main Breaker
Type Icu(kA)
NF100-CP 10
NF100-SP 30
NF100-SP
T/A 30
NF100-HP 50
NF100-HP
T/A 50
NF100-SEP 25
NF100-HEP 50
NF160-SP 25
NF160-SP
T/A 25
NF160-HP 50
NF160-HP
T/A 50
NC250-CP 15
NF250-CP
T/A 15
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
~
~
~
~
64
Branch Breaker Ics(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
440VAC (Sym. kA)
Rated current
(A)
AE630-SS AE1000-SS AE1250-SS AE1600-SS
65 65 65 65
Type Icu(kA)
500 600 700 800 900 1000315 378 441 504 567 630 800 960 1120 1280 1440 1600625 750 875 1000 11251250
Selective limit current
In=500 .... 6(25) 630 .... 7(25) 800 .... 11(25) 1000 .... 14(25) 1250 .... 19(25) 1600 .... 25
NF250-SP 25
125
150
175
200
225
250
8
10 6
8
10
10
6
6
8
8
10
8
6
6
8
8
8
8
4
6
6
8
8
6
4
6
6
6
8
6
6
6
8
8
8
8
4
6
6
6
8
6
4
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
4
4
4
6
6
6
8
6
3
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
4
4
3
3
4
4
3
3
3
3
4
3
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
3
3
3
3
4
3
3
3
3
3
3
3
Selective limit current
In=500 .... 6(25) 630 .... 7(25) 800 .... 11(25) 1000 .... 14(25) 1250 .... 19(25) 1600 .... 25
NF250-SP
T/A 25
100 125
125 160
150 200
200 250
4
4
6
8
3
3
6
6
3
3
4
6
3
3
4
63
43
4
3
3
6
6
3
3
4
6
3
3
4
43
43
33
3
3
3
4
43
43
33
33
6
6
10
6
6
8
10
6
6
8
8
4
4
6
8
4
4
6
6
3
3
6
6Selective limit current
In=500 .... 7(50) 630 .... 9(50) 800 .... 12(50) 1000 .... 15(50) 1250 .... 25(50) 1600 .... 42(50)
NF250-HP 50
125
150
175
200
225
250
8
10 6
8
10
10
6
6
8
8
10
8
6
6
8
8
8
8
4
6
6
8
8
6
4
6
6
6
8
6
6
6
8
8
8
8
4
6
6
6
8
6
4
4
6
6
6
6
3
4
4
6
6
6
3
3
4
4
6
4
3
3
4
4
4
4
4
6
6
6
8
6
3
4
6
6
6
6
3
4
4
6
6
4
3
3
4
4
4
4
3
3
4
4
3
3
3
3
4
3
3
4
4
6
6
4
3
3
4
4
6
4
3
3
4
4
3
3
3
3
4
3
3
3
3
3
3
3
Selective limit current
In=500 .... 7(50) 630 .... 9(50) 800 .... 12(50) 1000 .... 15(50) 1250 .... 25(50) 1600 .... 42(50)
NF250-HP
T/A 50
100 125
125 160
150 200
200 250
4
4
6
8
3
3
6
6
3
3
4
6
3
3
4
63
43
4
3
3
6
6
3
3
4
6
3
3
4
43
43
33
3
3
3
4
43
43
33
33
6
6
10
6
6
8
10
6
6
8
8
4
4
6
8
4
4
6
6
3
3
6
6Selective limit current
In=500 .... 6(25) 630 .... 7(25) 800 .... 11(25) 1000 .... 14(25) 1250 .... 19(25) 1600 .... 25
NF250-SEP 25
125
150
175
200
225
250
6
6
8
8
10
10
6
6
6
8
8
10
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
4
6
3
3
4
4
4
3
3
3
4
4
3
3
3
4
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
3
3
3
4
3
3
33
3
3
3
4
4
4
3
3
3
4
3
3
33
33
Selective limit current
In=500 .... 6(50) 630 .... 7(50) 800 .... 11(50) 1000 .... 14(50) 1250 .... 19(50) 1600 .... 25(50)
NF250-HEP 50
125
150
175
200
225
250
6
6
8
8
10
10
6
6
8
8
8
10
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
4
6
3
4
4
4
4
3
3
4
4
4
3
3
3
4
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
3
3
3
4
3
3
33
3
3
3
4
4
4
3
3
4
4
3
3
33
33
Selective limit current
In=500 .... – 630 .... 9.4(25) 800 .... 12(25) 1000 .... 15(25) 1250 .... 18(25) 1600 .... 24(25)
NF400-CP 25
250
300
350
400
66
64
6
6
4
6
6
6
4
4
6
6
66
64
6
6
4
4
6
6
3
4
4
6
3
4
4
6
4
6
6
4
4
6
6
3
4
4
6
3
3
4
4
3
3
4
4
3
3
4
66
Selective limit current
In=500 .... – 630 .... 9.4(42) 800 .... 12(42) 1000 .... 15(42) 1250 .... 18(42) 1600 .... 24(42)
NF400-SP 42
250
300
350
400
88
88
8
8
6
6
8
6
6
8
8
86
86
8
8
6
6
8
8
4
6
6
8
4
6
6
6
8
8
8
6
6
8
8
4
6
6
8
4
6
6
8
4
4
6
6
3
4
4
6
88
Selective limit current
In=500 .... 7.5(42) 630 .... 9.4(42) 800 .... 12(42) 1000 .... 15(42) 1250 .... 18(42) 1600 .... 24(42)
NF400-SEP 42
200
225
250
300
350
400
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
4
4
4
6
6
8
3
4
4
4
6
6
3
3
4
4
4
6
3
3
3
4
4
3
3
3
4
3
3
4
Selective limit current
In=500 .... 7.5(65) 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 18(65) 1600 .... 24(65)
NF400-HEP 65
200
225
250
300
350
400
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
3
4
4
6
6
6
3
3
4
4
6
6
3
3
3
4
4
6
3
3
3
4
4
4
4
4
6
6
8
3
4
4
4
6
6
3
3
4
4
4
6
3
3
3
4
4
3
3
3
4
3
3
4
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
65
Ics(kA)
Type
Rated current
(A)
AE2000-SS AE2500-SS AE3200-SS
AE4000-SSC
85 85 85 85
1250 1500 1750 2000 2250 250010001200 1400 1600 1800 2000 3200 3600 40001600 1920 2240 2560 28803200
Selective limit current
In=1000 .... 14(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
125
150
175
200
225
250
3
3
4
4
4
4
3
3
3
4
3
3
3
3
3
3
33
3
3
3
4
3
3
3
3
3
3
33
33
100 125
125 160
150 200
200 250
Selective limit current
In=1000 .... 14(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
3
43
33 3
33
Selective limit current
In=1000 .... 15(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
125
150
175
200
225
250
3
3
4
4
4
4
3
3
3
4
3
3
3
3
3
3
33
3
3
3
4
3
3
3
3
3
3
33
33
100 125
125 160
150 200
200 250
Selective limit current
In=1000 .... 15(50) 1600 .... 42(50) 2000 .... 50 2500 .... 50 3200 .... 50 4000 .... 50
3
43
33 3
33
Selective limit current
In=1000 .... 14(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
125
150
175
200
225
250
3
3
3
4
3
3
33 3
33
Selective limit current
In=1000 .... 14(25) 1600 .... 25 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
125
150
175
200
225
250
3
3
3
4
3
3
33
33
250
300
350
400
Selective limit current
In=1000 .... 15(25) 1600 .... 24(25) 2000 .... 25 2500 .... 25 3200 .... 25 4000 .... 25
4
4
6
6
3
4
4
6
3
3
4
4
3
3
4
3
3
33
3
3
4
4
6
3
3
3
4
3
3
33
333
3
3
43
33
250
300
350
400
Selective limit current
In=1000 .... 15(42) 1600 .... 24(42) 2000 .... 30(42) 2500 .... 39(42) 3200 .... 42 4000 .... 42
6
6
8
8
4
6
6
6
4
4
6
6
3
4
4
6
3
3
4
4
3
3
4
4
4
6
6
6
3
4
6
6
3
4
4
6
3
3
4
4
3
3
4
3
3
3
3
4
4
6
3
3
4
4
3
3
4
3
3
33
333
Selective limit current
In=1000 .... 15(42) 1600 .... 24(42) 2000 .... 30(42) 2500 .... 39(42) 3200 .... 42 4000 .... 42
200
225
250
300
350
400
3
3
4
4
6
6
3
3
3
4
4
4
3
3
4
4
3
3
4
3
3
33
3
3
3
3
4
4
3
3
3
3
3
3
33
33
3
3
43
33
Selective limit current
In=1000 .... 15(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 39(65) 3200 .... 48(65) 4000 .... 62(65)
200
225
250
300
350
400
3
3
4
4
6
6
3
3
3
4
4
4
3
3
4
4
3
3
4
3
3
33
3
3
3
3
4
4
3
3
3
3
3
3
33
33
3
3
4
3
3
43
Branch Breaker
Main Breaker
Type Icu(kA)
NF250-SP 25
NF250-SP
T/A 25
NF250-HP 50
NF250-HP
T/A 50
NF250-SEP 25
NF250-HEP 50
NF400-CP 25
NF400-SP 42
NF400-SEP 42
NF400-HEP 65
Icu: Rated breaking capacity
~
~
~
~
~
~
~
~
66
Branch Breaker Ics(kA)
Type
Main Breaker
SELECTIVE-INTERRUPTION COMBINATIONS (DISCRIMINATION)
440VAC (Sym. kA)
Rated current
(A)
AE630-SS AE1000-SS AE1250-SS AE1600-SS
65 65 65 65
Type Icu(kA)
500 600 700 800 900 1000315 378 441 504 567 630 800 960 1120 1280 14401600625 750 875 1000 11251250
In=500 .... – 630 .... – 800 .... – 1000 .... – 1250 .... 18.7(50) 1600 .... 24(50)
Selective limit current
NF630-CP 50
500
600
630
66
866
66
6
6
4
6
6
In=500 .... – 630 .... – 800 .... – 1000 .... – 1250 .... 18.7(50) 1600 .... 24(50)
Selective limit current
NF630-SP 50
500
600
630
88 1088
8
8
6
8
8
Selective limit current
In=500 .... 7.5(65) 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF630-SEP 85
300
350
400
500
600
630
88
86
8
8
8
8
10
6
8
8
6
6
8
10
6
6
6
10
10
4
6
6
8
8
8
6
8
8
6
6
8
6
6
6
8
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
8
6
6
8
10
6
6
6
10
10
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
6
6
6
4
4
4
4
6
6
Selective limit current
In=500 .... – 630 .... 9.4(65) 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF630-HEP 100
300
350
400
500
600
630
88
86
8
8
8
8
10
6
8
8
6
6
8
10
6
6
6
10
10
4
6
6
8
8
8
6
8
8
6
6
8
6
6
6
8
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
8
6
6
8
10
6
6
6
10
10
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
6
6
6
4
4
4
4
6
6
Selective limit current
In=500 .... – 630 .... – 800 .... 12(50) 1000 .... 15(50) 1250 .... 18.7(50) 1600 .... 24(50)
NF800-CEP 50
400
450
500
600
700
800
88
8
8
6
8
8
6
6
8
8
66
86
8
8
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
8
8
8
6
8
8
8
6
6
6
8
8
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
8
Selective limit current
In=500 .... – 630 .... – 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF800-SEP 85
400
450
500
600
700
800
88
8
8
6
8
8
6
6
8
8
66
86
8
8
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
8
8
8
6
8
8
8
6
6
6
8
8
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
8
Selective limit current
In=500 .... – 630 .... – 800 .... 12(65) 1000 .... 15(65) 1250 .... 18.7(65) 1600 .... 24(65)
NF800-HEP 100
400
450
500
600
700
800
88
8
8
6
8
8
6
6
8
8
66
86
8
8
6
6
8
8
6
6
6
8
8
4
6
6
6
8
8
8
8
8
6
8
8
8
6
6
6
8
8
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
8
Icu: Rated breaking capacity
67
Ics(kA)
Type
Rated current
(A)
AE2000-SS AE2500-SS AE3200-SS
AE4000-SSC
85 85 85 85
1250 1500 1750 2000 2250 250010001200 1400 1600 1800 2000 3200 3600 400016001920 2240 2560 28803200
Selective limit current
In=1000 .... – 1600 .... 24(50) 2000 .... 30(50) 2500 .... 37(50) 3200 .... 50 4000 .... 50
500
600
630
66
6
6
4
6
6
4
6
6
4
4
6
6
86
6
6
4
6
6
4
4
6
4
4
4
4
4
4
4
6
6
4
4
6
4
4
4
4
4
4
4
4
44
44
44
44
Selective limit current
In=1000 .... – 1600 .... 24(50) 2000 .... 30(50) 2500 .... 37(50) 3200 .... 50 4000 .... 50
500
600
630
88
8
10
6
8
8
6
6
8
6
6
6
86
8
8
6
8
8
6
6
6
4
6
6
4
6
6
6
8
8
6
6
6
4
6
6
4
6
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Selective limit current
In=1000 .... 12(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 37(65) 3200 .... 63(65) 4000 .... 85
300
350
400
500
600
630
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
6
6
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
44
44
44
4
Selective limit current
In=1000 .... 12(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 37(65) 3200 .... 63(65) 4000 .... 85
300
350
400
500
600
630
4
6
6
8
8
8
4
4
6
6
8
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
6
6
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
44
44
44
4
Selective limit current
In=1000 .... 12(50) 1600 .... 24(50) 2000 .... 30(50) 2500 .... 37(50) 3200 .... 50 4000 .... 50
400
450
500
600
700
800
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Selective limit current
In=1000 .... 12(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 37(65) 3200 .... 63(65) 4000 .... 85
400
450
500
600
700
800
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Selective limit current
In=1000 .... 12(65) 1600 .... 24(65) 2000 .... 30(65) 2500 .... 37(65) 3200 .... 63(65) 4000 .... 85
400
450
500
600
700
800
6
6
8
8
6
6
6
8
8
4
4
6
6
8
8
4
4
4
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
6
6
6
8
8
4
4
6
6
6
8
4
4
4
6
6
6
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
6
6
8
4
4
4
4
6
6
4
4
4
4
4
6
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Branch Breaker
Main Breaker
Type Icu(kA)
NF630-CP 50
NF630-SP 50
NF630-SEP 85
NF630-HEP 100
NF800-CEP 50
NF800-SEP 85
NF800-HEP 100
Icu: Rated breaking capacity
68
6.4 Cascade Back-up Protection
6.4.1 Cascade Back-up Combinations
Following tables show the available MCCB combina-
tions for cascade interruption and their interrupting
capacity.
Fault point
Branch
breaker Branch
breaker
Main breaker
Main
MCCB
S
C
NF30-SP
MB30-SP
MB50-CP
MB50-SP
NF50-HP
NF60-HP
NF50-HRP
NF100-SP
MB100-SP
NF100-HP
NF160-SP
NF160-HP
NF250-SP
MB225-SP
NF250-HP
NF400-SP
NF400-SEP
NF630-SP
NF630-SEP
NF50-CP
NF60-CP
NF630-CP
NF250-CP
NF100-CP
NF400-CP
2.510145555 535
125
35 50
14 20 15 10 15 10 15 10 10 10 10 10 10 10 10 10 10 10 50
125
50 50 10 10 10 10
20 30 18 18 15 15 15 14 14 14
125 125
50 50
50 42 42
125 200 125 200 200
85 85
50 42 42 35 35 35 35 35 35 35 35 35 30
125 200 125 200
50 50 35 30
65 65 65 65 65 65
125 200 125 200 200
85 85 65
35 50 50 50 35 50 50 35 50 50
125 200
85 85 85
65 65 65 65 65 65 65
125 200 200 200 200
65
35 50 50 35 50 50 35 50 50
125 200
85 85 85
65 65 65 65 65 65
125 200 200 200 200
65
65 65 65 65 65 65
200 200 200
65 65 65 65
200 200
10145555 535
125
35 50 5
20 30 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14
125 200
50
125
14 14 14 14
25 25 25 25 30 30 30 25 25 25 20 20 20 20 20 20 18 18 18
125 200
50 30 25 20
35 35 35 35 35 35 35 35 35 30 30 30 50 50 50 30
42 50 50 42 50 50 42 42 42
200 200
42
25 50 25 50 25 50 50 65
125
50 65
125
50 65
125
85 85 85 15 25 35 35
125 200 125 200 200 200 200 125
7.5
10
30
25
25
25
50
50
35
25
15
10
2.5
50
50
50
Branch
MCCB
440VAC
Interrupting capacity (kA)
NF100-SP
NF100-HP
NF160-SP
NF160-HP
NF250-SP
NF250-HP
NF400-SP
NF400-HEP
NF400-REP
NF630-SP
NF630-HEP
NF630-REP
NF800-SEP
NF800-HEP
NF800-REP
NF400-CP
NF630-CP
NF225-RP
NF225-UP
NF400-UEP
NF630-UEP
NF800-CEP
NF100-RP
NF100-UP
NF800-UEP
NF1250-UR
NF1000-SS, NF1250-SS, NF1600-SS
NF2000-S, NF2500-S
NF3200-S, NF4000-S
NF250-CP
S
CU
–
– – – – – – – – –– – – – – – –
–––– – – – – –
–– – –
– – – – – – – – – – –
– – – –
– – – – – – –
– – – –– – – –– –– – – –––
––– – – – – –
– – – – – – – –
––––––––
– –
– – – – – – –
–
–––––
– – – ––––––
––––––
– –
–
– – – –
– – – – – –
–––––
– – – – – – – –
––
– – – – – – –
––––
– – – – – – – – – –
––––
– – – – –
– – – – – –
– – – – – –
–––
–
–
– –
–
––––
––––––
––––––
––
––
–– –– –– – ––
–– –– ––
–
–
–
–
–
–
– – –
– – – –
– –
– – –
69
Main
MCCB
S
C
NF30-SP
MB30-SP
MB50-CP
MB50-SP
NF50-HP
NF60-HP
NF50-HRP
NF100-SP
MB100-SP
NF100-HP
NF160-SP
NF160-HP
NF250-SP
MB225-SP
NF250-HP
NF400-SP
NF400-SEP
NF630-SP
NF630-SEP
NF50-CP
NF60-CP
NF630-CP
NF250-CP
NF100-CP
NF400-CP
5 425010101010 7.5
125 200
35 50
42 85 35 35 35 35 30 30 30 30 30 30 25 14 14
125 200
85
125
50
100
50 50 50 50 50 50 50 50 50 50 30 30
125 200
85
125
125 200 125 200 200 125 125
100
85 85 85 85 85 85 85 85
125 200 125 200 200 125 125
125 200 125 200 200 125 125
85 85 85 85 85 85 85 85 70 70 70 70
125 200 200 125 125
70
125 200 200 200 200
85 85 85 85 85 85 85 85 70 70 70 70
125 200 200 125 125
70
125 200 200 200 200
100 100 100 200 200 200 100
100 100 100 200 200 100
35 50 10 10 10 10 7.5
125 200
35 50
35 85 50 50 50 50 50 50 50 50 50 50 30 30
125 200
85
125
50 50
50 50 50 50 50 50 50 50 50 50 35 35
125 200 200
50 50
85 85 85 85 85 85 85 85 85 85 85 85
200 200 200
85
85 85 85 85 85 85 85 85 85
200 200
85
50
100
50
100
50
100
85
100 125
85
100 125
85
100 125 125 125 125
30 50 50 50
125 200 125 200 200 200 200 170
10
25
85
50
50
50
100
100
50
35
30
25
5
85
85
100
Branch
MCCB
230VAC
Interrupting capacity (kA)
NF100-SP
NF100-HP
NF160-SP
NF160-HP
NF250-SP
NF250-HP
NF400-SP
NF400-HEP
NF400-REP
NF630-SP
NF630-HEP
NF630-REP
NF800-SEP
NF800-HEP
NF800-REP
NF400-CP
NF630-CP
NF225-RP
NF225-UP
NF400-UEP
NF630-UEP
NF800-CEP
NF100-RP
NF100-UP
NF800-UEP
NF1250-UR
NF1000-SS, NF1250-SS, NF1600-SS
NF2000-S, NF2500-S
NF3200-S, NF4000-S
NF250-CP
S
CU
– – – – – – – –– – – – –
– – – – – –
– – – – – –
–––––––––––––
–––
– – – – –
– – – – – –
– – –
–
–
––––
–––––––––––––
––––
– – –
–––––––––––––
––––
– – –
––––––––––––– – –
––––––––––––– – –
–
– – ––––
– – ––––
––––
–
– – – –
– – – –
– – – –
–
–
–
–
–
– – – – –
– –
– –
–––
– – ––––
– –
– – ––––
–––––––––––––
–––––––––
––––––
––
– –
––––––– – – – – –
– – – –– – –
– – – –
– – –
–
–
– – – – –
– – –
––
– –
– – – – –
– – – – – –– – –
– – –
– – – – –
– – –– – – – –
–
– –
–
70
6.5 I2t let-Through and Current Limiting Characteristics
I2t let-through characteristics Current limiting characteristics
NF100-HP,NF250-HP
short-circuit current,sym.r.m.s.(kA)
1 2 4 10 20 40 60 8010086
100
80
60
40
20
10
8
6
4
2
1
Max. Iet-through current(kA)
NF250-HP
NF100-HP(30A)
NF100-HP(20A)
NF100-HP(15A)
NF100-HP
(40~100A)
Prospective short-circuit
current,asym.peak
NF400-UEP,NF630-UEP,NF800-UEP
short-circuit current,sym.r.m.s.(kA)
1 2 4 10 20 40 60 80100 20086
100
200
400
80
60
40
20
10
8
6
4
2
1
Max. Iet-through current(kA)
NF630-UEP
NF800-UEP
NF400-UEP
Prospective short-circuit
current,asym.peak
NF100-RP,NF100-UP,NF225-RP,NF225-UP
short-circuit current,sym.r.m.s.(kA)
3 10 20 50 100 200
100
200
50
30
20
10
5
1
Max. Iet-through current(kA)
NF225-UP
NF225-RP NF100-UP
NF100-RP
Prospective short-circuit
current,asym.peak
NF100-RP,NF100-UP,NF225-RP,NF225-UP
Max. I
2
t (A
2
-sec)
( 10
6
)
short-circuit current,sym.r.m.s.(kA)
3 10 20 50 100 200
10
20
5.0
2.0
1.0
0.5
0.2
0.1
0.05
NF225-UP
NF225-RP
NF100-UP
NF100-RP
NF400-UEP,NF630-UEP,NF800-UEP
Max. I
2
t (A
2
-sec)
( 10
6
)
short-circuit current,sym.r.m.s.(kA)
1 2 4 10 20 40 60 80100 20086
10
20
40
8
6
4
2
1
0.8
0.6
0.4
0.2
0.1
NF630-UEP
NF800-UEP
NF400-UEP
NF100-HP,NF250-HP
short-circuit current,sym.r.m.s.(kA)
1 2 4 10 20 40 60 8010086
10
8
6
4
2
1
0.8
0.6
0.4
0.2
0.1
Max. I
2
t (A
2
-sec)
NF250-HP
NF100-HP
(30A)
NF100-HP
(20A)
NF100-HP
(15A)
NF100-HP
(40~100A)
( 10
6
)
71
Table 6.4 Allowable Fault Conditions in Conductors
6.6 Protective Coordination with Wiring
6.6.1 General Considerations
If it is assumed that the heat generated by a large
current passing through a wire is entirely dissipated
within the wire, the following expression is applicable
(for copper wires):
(
S
I
2
t=5.05✕10
log
4e
234+T
234+To
)
I: Current(A, rms)
S : Wire cross-sectional area(mm2)
t : Current let-through time(sec)
T : Wire temperature due to short circuit(°C)
To : Wire temperature before short circuit(°C)
Assume that short-circuit current occurs in a wire car-
rying its rated current (hot state To=60°C). If 150°C is
the allowable temperature T, the following expression
is applicable (see also Fig. 6.13):
Is
Allowable short-circuit
current accoeding to I2t
kA, sym. (PF)
1
1.5
2.5
4
6
10
16
25
35
50
70
95
120
150
185
240
Allowable I2t
A2✕sec
S
Wire size
mm2
Notes: 1. Allowable I2t is calculated assuming that
all heat energy is dissipated in the
conductor, conductor allowable maximum
temperature exceeds 150°C, and hot
start is applied, at 60°C.
2. Is is an asym. value of allowable short-
circuit current reduced to below the
allowable I2t, assuming half cycle
interruption for 16mm2 or less and one
cycle interruption for 25mm2 or more.
Allowable I2t=14000S2
Considering let-through energy (∫i2dt) in a fault where
the protector has no current-limiting capability, if short-
circuit occurs when let-through current is max., ∫i2dt
is:
where current le is the effective value of the AC com-
ponent. Half-cycle interruption is applied to wire of up
to 14mm2, and one-cycle interruption to larger wires.
Table 6.4 is restrictive in that, e.g., in a circuit of fault
capacity of 5000A or more, 2.5mm2 wires would not
be permitted. In practice, the impedance of the con-
ductor itself presents a limiting factor, as does the in-
herent impedance of the MCCB, giving finite let-
through I2t and Ip values that determine the actual
fault-current flow.
6.6.2 600V Vinyl-Insulated Wire (Overcurrent)
Japanese Electrical Installations Technical Standards
(domestic) specify vinyl-insulated wire operating tem-
perature as 60°C max., being a 30°C rise over a 30°C
ambient temperature. This is to offset aging deterio-
ration attendant on elevated temperatures over long
periods. Criteria for elevated temperatures over short
periods have been presented in a study by B. W. Jones
and J. A. Scott (“Short-Time Current Ratings for Air-
craft Wire and Cable,” AIEE Transactions), which pro-
poses 150°C for periods of up to 2 seconds, and 100°C
for periods in the order of 20 seconds. These criteria
can be transposed to currents for different wire sizes
by the curves given in Fig. 6.14. Such figures, how-
ever, must be further compensated for the difference
between vinyl materials used for aircraft and for
0.014✕106
0.032✕106
0.088✕106
0.224✕106
0.504✕106
1.40✕106
3.58✕106
8.75✕106
17.2✕106
35.0✕106
68.6✕106
126✕106
202✕106
315✕106
479✕106
806✕106
1.17 (0.9)
1.76 (0.9)
2.93 (0.9)
4.68 (0.9)
6.79 (0.8)
10.5 (0.6)
16.0 (0.5)
17.3 (0.3)
24.2 (0.3)
34.5 (0.3)
48.3 (0.3)
65.6 (0.3)
82.8 (0.3)
103 (0.3)
128 (0.3)
166 (0.3)
Fig. 6.13 Temperature Rises Due to Current Flow in Copper Wires
×10
3
×10
4
Temperature rise(°C)
1000
700
500
300
200
100
20
30
50
70
12 23344567856 1
(A/mm
2
)
2
·sec
Approx. 71
Ie
2
(A ·sec) in
2
2
1cycle interruption
(Power factor is 0.5.)
Approx. 34
Ie
2
(A ·sec) in 1
2
cycle interruption
(Power factor is 0.3.)
72
Fig. 6.14 Relation of Let-through Current to Time until 600V Vinyl-Insulated Wire Reaches a 70°C Temperature Rise.
(In a Start from No Load State at Ambient Temperature of 30°C)
Fig. 6.15 MCCBs and Wiring Sizes
15
20
30
40
50
60
75
100
125
150
175
200
225
250
300
350
400
Wire size
(mm2)
MCCB
rating(A)
1
1.5
2.5
4
6
10
16
25
35
50
70
95
120
185
240
Unprotected region
Protected region
Fig. 6.16 Wire Derating Method, for Conduit Routing
Current (×10
2
A)
Time (sec)
1000
800
600
500
10
0.2
0.4 0.50.6
0.3 10.8 2 3
10
9203040
50 100 1000200 300 5008060
876540.1
6
5
4
3
2
1
20
30
40
50
60
100
200
300
400
630
185
150
120
95
70
50
35
25
16
10
6.0
4.0
2.5
1.5
1.0
500
400
300
240
Wire sizes (mm
2
)
=Correction factor
Time.
!
2
!
1
!
1
!
2
Current
Open wiring
Routed in conduit
ground use; ultimately, the temperature figure of 75°C
is derived (100°C per Jones and Scott, compensated)
as a suitable short-time limitation for wiring with heat-
proof vinyl or styrene-butadene-rubber insulation.
Current transpositions for the range of wire sizes are
not presented, being non-standard ; however, Fig. 6.15
gives MCCB ratings for temperature limitations of 30°C
in normal operation, and 75°C for periods of up to 20
seconds.
The apparent disparity of the ambient ratings of 30°C
for wiring against 40°C for MCCBs, is reconcilable in
that wiring, for the most part, is externally routed, while
MCCBs are housed in panelboards or the like. The
two figures can be used compatibly, without modifi-
cation. It is further noted that, where MCCBs with long-
delay elements of the thermal type are employed, the
effect of increased ambient, which would normally
derate the wiring, is adequately compensated by the
attendant decrease in thermal-region tripping time of
the MCCB.
The curves in Fig. 6.17 show the comparison of the
delay regions of MCCB tripping with allowable cur-
rents in open-routed wiring. Fig. 6.16 shows the
method required by the Japanese standards referred
to above, for derating wiring to be routed in conduit.
73
Fig. 6.17 600V Wire and MCCB Protection Compatibility
2000
1000
100
200
300
400
600
800
10
20
30
40
60
80
1
0.8
10 100 1000 10000
Current (A)
a) 50A-fream MCCB
Tripping time (sec)
0.6
0.5
2
3
4
6
8
2000
1000
100
200
300
400
600
800
10
20
30
40
60
80
1
0.8
10 100 1000 10000
Current (A)
c) 225A-fream MCCB
Tripping time (sec)
0.6
0.5
2
3
4
6
8
2000
1000
100
200
300
400
600
800
10
20
30
40
60
80
1
0.8
100 1000 10000 100000
Current (A)
d) 400A-fream MCCB
Tripping time (sec)
0.6
0.5
2
3
4
6
8
2000
1000
100
200
300
400
600
800
10
20
30
40
60
80
1
0.8
10 100 1000 10000
Current (A)
b) 100A-fream MCCB
Tripping time (sec)
0.6
0.5
2
3
4
6
8
MCCB rating
15A
MCCB rating
125A
MCCB rating
250A
300A
350A
400A
150A
175A
200A
225A
20A
30A
40A
50A
Wire size
1.0mm
2
Wire size
16mm
2
Wire size
50mm
2
70mm
2
95mm
2
120mm
2
150mm
2
25mm
2
35mm
2
50mm
2
70mm
2
MCCB rating
60A
75A
100A
Wire size
10mm
2
16mm
2
25mm
2
1.5mm
2
2.5mm
2
4.0mm
2
6.0mm
2
74
6.7
Protective Coordination with Motor Starters
Motor starters comprise a magnetic contactor and a
thermal overload relay, providing the nesessary
switching function for control of the motor, plus an
automatic cutout function for overload protection.
Mitsubishi Electric’s excellent line of motor starters
are available for a wide range of motor applications
and are compatible with Mitsubishi MCCBs.
Magnetic contactors are rugged switching devices
required to perform under severe load conditions with-
out adverse affect. They are divided into Classes A
through D (by capacity); Class A, e.g., must be able
to perform 5 cycles of closing and opening of 10 times
rated current, followed by 100 closing operations of
the same current after grinding off 3/4 of the contact
thickness.
Current ratings of contactors usually differ according
to the circuit rated voltage, since voltage determines
arc energy, which limits current-handling capability.
Thermal overload relays (OLRs) employ bimetal ele-
ments (adjustable) similar to those of MCCBs.
For compatibility with the magnetic contactor, the OLR
must be capable of interrupting 10 times the motor
6.7.2 Levels of Protection (Short Circuit)
In some cases it may be advantageous to allow the
starter to be damaged in the event of a short circuit,
provided that the fault is interrupted and the load side
is properly protected.
IEC standards defines 2 types of coordination, sum-
marized as:
1. Type “1” coordination requires that, under short-
circuit conditions, the contactor or starter shall
cause no danger to persons or installation and
may not be suitable for further service without re-
pair and replacement of parts.
2. Type “2” coordination requires that, under short-
circuit conditions, the contactor or starter shall
cause no danger to persons or installation and
shall be suitable for further use. The risk of con-
tact welding is recognized, in which case the
manufacturer shall indicate the measures to be
taken as regards the maintenance of the equip-
ment.
Fig. 6.18 Protective Coordination; MCCBs and Motor Starters
MCCB
Magnetic contactor
and thermal overload
relay
Protection function
MCCB
Starter
combination Protects the motor against overcurrents up
to 10 times rating.
Protects circuit wiring' control devices' and
OLR against fusion.
Motor normal starting
current
OLR-MCCB curve
intersection
Transient peak of
motor current
Time
Motor overheat/burnout curve
MCCB trip. curve
OLR trip. curve
Current-time limitations of motor wiring
Intersection of MCCB and OLR trip curves
OLR heater fusion
Current-time limitations of
MCCB-to-starter wiring
234 56
Current
Key
MCCB inst. trip current
Protection limit; the
possible short-circuit at
the motor terminals must
be less than this value.
MCCB rated interruption
capacity
Motor starting
current
Fig. 6.19 Protection Coordination Criteria for MCCBs and
Motor Starters
full-load current without destruction of its heater ele-
ment. Mitsubishi Type TH OLRs are normally capable
of handing 12 to 20 times rated current; in addition
there is available a unique saturable reactor for par-
allel connection to the heaters of some types, giving
a fusion-proofing effect of 40~50 times.
6.7.1 Basic Criteria for Coordination
It is necessary to ensure that the MCCB does not trip
due to the normal starting current, but that the OLR
cutout curve intersects the MCCB thermal delay-trip-
ping curve between normal starting current and 10
times full-load current. The MCCB instantaneous-trip-
ping setting should be low enough to protect the OLR
heater element from fusion, in a short-circuit condi-
tion.
The above criteria should ensure that either the MCCB
or the OLR will interrupt an overload, to protect the
motor and circuit wiring, etc. In practice it is desirable
for the MCCB instantaneous tripping to be set for about
15 times full-load current as a margin against tran-
sients, such as in reclosing after power failure, Y-delta
switching, inching, etc.
1
1. 4.
5.
6.
2.
3.
75
6.7.3 Motors with Long Starting Times
The usual approach is to select a starter with a larger
current rating, but this method, of course, involves a
degree of sacrifice of protection. Mitsubishi provides
a unique solution to this problem in the form of a satu-
rable reactor added to the OLR heater element. The
effect is to change the high-current characteristics,
so that nuisance tripping in starting is eliminated, with-
out loss of overload protection. Mitsubishi saturable
reactors are adjusted to allow around 25~30 seconds
of continuous starting current.
6.7.4 Motor Breakers (M Line MCCBs) and
Magnetic Contactors
M Line MCCBs are provided with trip curves espe-
cially suitable for motor protection, with ratings based
on motor full-load currents. They provide overcurrent
and short-circuit protection, and are normally used with
magnetic contactors. The need for protective coordi-
nation (as with a regular MCCB plus a starter) is elimi-
nated, and the reliability of protection in a short-cir-
cuit condition is far higher than that of the heater of a
starter OLR. Where the motor starting time is long,
the MCCB tripping curve must be checked carefully,
since tripping times are rather short in the delay-trip
range. Care must also be taken with respect to surge
conditions such as inching, reversing, restart, Y-delta
starting, etc.
6.7.5 Motor Thermal Characteristics
Overload currents in motors can lead to burnout, or
insulation damage resulting in shock or fire hazard;
the basic approaches to protection are (summarized
from Japanese standards):
1. MCCB + magnetic contactor + OLR
2. Motor breaker + magnetic contactor
3. Motor breaker alone
In 1, the OLR is the primary interrupter of overload,
and being adjustable, can be set for the true load re-
quirement. Large overcurrent or short-circuit fault con-
ditions are interrupted by the MCCB instantaneous
trip. In 2, the motor breaker is the protector for both
overload and short-circuit, and not being adjustable
must be selected carefully, for best coordination with
the load concerned. In 3, since the MCCB is relied on
not only for all protective functions but also for switch-
ing, this arrangement should be reserved for applica-
tions requiring infrequent motor starting and stopping.
6.7.6 Motor Starting Current
Motor starting times of up to 15 seconds are generally
considered safe; more than this is considered
undesirable; more than 30 seconds is considered
dangerous and should be avoided wherever possible.
For instantaneous tripping considerations, the MCCB
is normally set to 600% of the motor full-load current,
for trouble-free line-starting of an induction motor.
More detailed consideration is required where short-
time inrush effects (current magnification) are involved,
such as in Y-delta switching, running restart, etc. Two
basic causations are as follows:
1. Superimposed DC Transient (Low Power-Factor
Effect) Fig. 6.20 shows that the power factor is about
0.3 at starting, causing a significant DC component,
so that the total transient inrush current may reach
about twice the value of the AC component, even
though the latter is of constant amplitude. Peak in-
rush current (lt) of 1.4 x normal starting current (lo)
must be allowed for, in selecting the MCCB instanta-
neous-trip setting.
2. Residual Voltage (Running Restart)
If residual (regenerative) voltages appearing at the
motor terminals are out of phase with the supply volt-
age (at the time of reclosing after being interrupted,
before the motor speed is substantially reduced), the
cumulative effect of the line voltage and the residual
voltage is equivalent to the motor being directly sub-
jected to a large line overvoltage, with a resulting ab-
normal inrush current of:
Residual+source V
Source V ✕Normal starting inrush current
This is a current magnification effect, which may be
as much as 2 x in direct restarting, and
1+
3
1
( )
x in Y-
delta-switching restarting. When the DC-transient fac-
tor (§1 above) is added, the magnification becomes
2.4 in the case of direct restarting, and 1.9 for Y-delta
restarting.
Fig. 6.21 Peak Inrush-Current Measurements
Fig. 6.20 Transient DC Component
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
It
2
Io
It 0
Power factor (lag)
0.1 0.2 0.3 0.4 0.5 0.6 0.7
Io
Current magnification
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
0.2 0.4 0.75 1.5 2.2 3.7 5.5 7.5 22
30
Motor output (kW)
b) Test results a) Test connections
Contactor
Backup
MCCB
CT
Motor
breaker
Oscillo-
graph
Direct (line) starting
Inching duty
Reversing duty
-delta switching
M
~
76
Fig. 6.23 Coordinated PF and MCCB Characteristics
6.8.2 Electronic MCCBs and HV PF
A basic requirement is that the deteriorated short-de-
lay curve of the PF, and the short-delay trip curve of
Electronic MCCB, which is shifted +10% along the
current axis, do not overlap.
To facilitate matching, the rated current of the PF
should be as large as possible; however, there is an
upper limit, as seen from the following criteria:
1. The rated current should be 1.5~2 times the load
current.
2. To ensure protection in the event of a short circuit,
the PF must interrupt a current of 25 times the trans-
former rating within 2 seconds.
3. To ensure that the PF neither deteriorates nor fuses
as a result of the transformer excitation surge
current, the short-delay deterioration curve of the
PF must be more than 0.1 seconds, at a current of
10 times the transformer rating. The “10 times”
factor becomes “15 times” in the case of a single-
phase transformer.
Thus, if normal starting current is assumed as 600%
of full-load current, the peak inrush becomes 1200%
in Y-delta restarting and 1600% in direct restarting.
The MCCB instantaneous-trip setting must be selected
at larger than these values.
Fig. 6.21 shows test date with respect to four condi-
tions of transient inrush current, expressed as magni-
fications of full-load current, measured on motors rated
from 0.2~30kW. The MCCB was used for line-start-
ing switching, and the contactor for the other switch-
ing duties. Phase matching between the line and re-
sidual voltages was uncontrolled.
The oscillographs taken showed that the peak inrush
currents persist for about one-half cycle, followed by
a rapid decrease to normal starting-current level. From
the curves it can be concluded that peak inrush mag-
nifications vary greatly depending on the duty involved;
for reversing duty, the MCCB instantaneous trip set-
tings must be selected from 1600 ~ 3400% of full-
load current. For line starting and Y-delta starting, the
range spans from 1000~2000%.
6.8 Coordination with Devices on the High-
Voltage Circuit.
6.8.1 High-Voltage Power Fuse
The MCCB on the secondary (low-voltage) side of a
power transformer must have tripping characteristics
that provide protective coordination with the power
fuse (PF) on the high-voltage side (Fig. 6.22). The
MCCB must always trip in response to overcurrent,
to ensure that the PF does not fuse or deteriorate by
elevated temperature aging.
Fig. 6.23 shows the MCCB curve in relationship to
the deteriorated PF curve (if this is unavailable, the
average fusing curve reduced by 20% can usually be
assumed). The PF characteristic can be converted to
the secondary side, or the MCCB characteristic to the
primary side; the curves must not overlap in the
overcurrent region.
Where the MCCB instantaneous-tripping current of
the MCCB is adjustable, difficulties in matching the
curves can be overcome as shown, but a 10% mar-
gin must be included to allow for the tolerance of the
MCCB tripping setting.
The shaded area in Fig. 6.23 belong to overcurrent
region, the overcurrent generally occur at the lower
circuit of MCCB2.
Thus, it may in some cases be better to accept a co-
ordination between the PF and MCCB2, permitting a
mismatch between the PF and MCCB1.
Fig. 6.22 Protective Coordination of MCCBs and HV-Side PF
PF
Tr
MCCB
1
MCCB
2
Time
MCCB tripping
curve
Minimum
setting of
inst,-trip
current
Short-delay fusing
of PF (deteriorated)
Overcurrent
77
6.8.3 MCCBs and HV-Side OCR
An overcurrent-relay remote tripping device (OCR) on
the HV side of the circuit must be coordinated with
the MCCBs on the LV side. The OCR setting must
take into consideration the coordination with the OCR
at the power-utility substation and, at the same time,
the following:
1. The setting of an OCR with an instantaneous-trip
element must be at least 10 times the transformer
current rating, to ensure that the excitation surge
of the latter does not trip the OCR.
2. To ensure short-circuit protection, the OCR must
operate within 2 seconds, at 25 times the
transformer rated current.
Figs. 6.26 and 6.27 show the setup, and the coordinat-
ed characteristics converted to the low-voltage side.
The turns ratio of the CT is 150:5, to match the rated
primary current of 87.5A. Considering cooperation of
the OCR with the upper-ranking substation OCR, the
OCR dial is normally set to 0.2 or less, or 1 second
max. if it has an instantaneous trip element. On the
Mitsubishi Type MOC-E general-purpose relay this is
equivalent to dial setting No. 2. Latching-curve over-
lap, shown by the broken lines in Fig. 6.27, must be
allowed for. The instantaneous trip is set to 30A, in
accordance with §1, above.
For setting the Electronic MCCBs (800 and 600A ver-
sions of Type NF800-SEP), the short-delay tripping
currents of both are set to MIN. NF800-SEP have neg-
ligible latching inertia, so that the reset characteris-
tics (except in the instantaneous-trip region) can be
regarded as the same as the tripping characteristics.
Further, there is very little tolerance variation between
units; thus, the tripping characteristics can be shown
as a single line.
If the NF800-SEP short-delay trip current is set at
MAX (where MIN and MAX respectively correspond
to 2 and 10 times rated current), a 600A rating setting
will correspond to 6000A tripping, and an 800A set-
ting will correspond to 8000A tripping. In this case (at
MAX setting), short-delay latching of the NF800-SEP
will overlap the OCR latching (4710A, secondary con-
version). But if the NF800-SEP and the OCR are all
set to MIN, so that the latching values do not exceed
4710A, good coordination will be achieved.
As the OCR has an instantaneous-trip element, set
at 30A (secondary conversion 28.3kA), the region of
selective interruption between the OCR and the
NF800-SEP will extend to this value.
Considering the coordination of the Electronic
MCCBs with the lower-level MCCBs (NF250-CP), it
NF250-CP
NF800-SEP
800A setting
CT ratio
150/5
CT
Tr
OCR
CB or S
Type MOC-E
5A tap
dial < 2
NF800-SEP
600A setting
6.6kV/210V
3f1000 kVA
Electronic MCCB
PF
Tr
Fig. 6.25 Coordinated PF and Electronic MCCB
Characteristics
3 hours
2
1 hour
40
30
20
10 min
6
4
1 min
40
30
20
10 sec
6
4
2
1 sec
0.6
0.4
0.2
0.1
0.06
0.02
0.01
0.006
0.004
0.002
Short-delay tripping
current setting range
Electronic MCCB
characteristic curve
Deteriorated
curve of PF
150
200
300
400
600
800
1,000 2,000 4,000 6,000 20,000 150,000
10,000 40,000
Current (A rms)
Time
Fig. 6.24 Protective Coordination of Electorinic MCCBs
and PF
Fig. 6.26 Electronic MCCBs in Coordination with an HV-
Side OCR
78
Fig. 6.27 Coordinated OCR and Electronic MCCB Characteristics
can be seen from Fig. 6.27 that the maximum trip curve
(tolerance) of the C Line units matches well with the
NF800-SEP curves, with no danger of overlap.
3 hours
2
1 hours
40
30
20
10 min
6
4
2
6
0.6
0.4
0.2
0.1
0.06
0.02
0.01
0.006
0.004
0.002
4
2
1 min
30
20
10 sec
1 sec
Time
150 300 600 1,000 4,000 10,000 40,000 80,000
200 400 800 6,000 20,000 60,0002,000
Current (A, rms)
NF800-SEP
800A setting
Max. MOC-E tripping curve
CT ratio 150/5
Tap 5
Dial #2
Latching curve
Inst. trip
setting 30A
NF250-CP
175A
Min.
Max.
Min.
79
7. SELECTION
In selecting MCCBs for a particular application, in
addition to purely electrical aspects of load and distri-
bution conductor systems, physical factors such as
panelboard configuration, installation environment,
ambient-temperature variations, vibration, etc. must
also be considered.
MCCBs are rated for an ambient of 40°C, and
where panelboard internal temperatures may exceed
this, the MCCBs installed should be derated in accor-
dance with Table 7.1.
1. Actual load currents may exceed the nominal-val-
ues.
2. Load currents may increase with time, due to dete-
rioration of load devices (i.e., friction in motors).
3. Source voltage and frequency may vary.
7.1 Motor Branch Circuits
The following discussion assumes single motors and
cold-start operation.
7.1.1 General Considerations
The starting current (IMS) and time (TMS) for the mo-
tor, and its full-load current, dictate the rated current,
long-delay trip and instantaneous-trip curves for the
MCCB as shown in Fig. 7.2. A safety-margin of up to
50% should be considered for the starting time, to
allow for voltage variations and increase in load fric-
tion.
The instantaneous-trip curve should be at least 1.4
x normal starting current to allow for the effect of the
DC component attendant to the low power factor
(about 0.3) of the starting current. For -delta start-
ing the unphased-switching allowance increases the
1.4 margin to 1.9. For running restarting the unphased-
switching allowance increases the factor to 2.4.
Rated currents
MCCB trip curve
Starting current
and long-delay trip
Inrush and
inst. trip
Motor
starting
current
TMS
IMS Current
Time
Fig. 7.2 MCCB and Motor Starting
7.1.2 Motor Breaker
Where starting times are relatively short and currents
are small, the Mitsubishi M Line motor breakers can
be used without the need for a motor starter.
7.2 For Lighting and Heating Branch Cir-
cuits
In such circuits, switching-surge magnitudes and times
are normally not sufficient to cause spurious tripping
problems; however, in some cases, such as mercury-
arc lamps or other large starting-current equipment,
the methods presented in §7.1 above should be con-
sidered.
In general, branch MCCBs should be selected so
that the total of ratings of the connected loads is not
more than 80% of the MCCB rating.
Fig. 7.1 MCCB Selection Consideration
Table 7.1 MCCB Deratings Due to Installation
Factors
Panelboard max.
internal temp. (°C)
50
55
60
Load allowable, due to
panelboard temp. (%)
90
80
70
Supply
system
Ambient
temperature
Main,submain
or branch use
Ambient
conditions
Wire
connection
Load
current
Operation
conditions
Load
Short circuit
Installation and
connection style
Service
purpose
Regulations
?
80
7.3 For Main Circuits
7.3.1 For Motor Loads
The method of “synthesized motors” is recommended
– that is, the branch-circuit loads to be connected are
divided into groups of motors to be started simulta-
neously (assumed), and then each group is regarded
as a single motor having a full-load current of the total
of the individual motors in the group. The groups are
regarded as being sequentially started.
The rating of the branch MCCB for the largest syn-
thesized motor is designated IB max., those of the
subsequent synthesized motors as I1, I2, ...In-1. The
rating of the main MCCB becomes:
IMAIN = IB max + (I1 + I2 +...In-1) x D
where D is the demand factor (assumed as 1 if inde-
terminate).
7.3.2 For Lighting and Heating, and Mixed Loads
For lighting and heating loads the rating of the main
MCCB is given as the total of the branch MCCB rat-
ings times the demand factor. For cases where both
motor-load branches and lighting and heating
branches are served by a common main MCCB, the
summation procedures are handled separately, as
described in the foregoing, then grand-totalized to give
the main MCCB rating.
7.4 For Welding Circuits
7.4.1 Spot Welders
A spot welder is characterized by a short, heavy in-
termittent load, switched on the transformer primary
side. The following points must be considered in
MCCB selection:
1. The intermittent load must be calculated in terms
of an equivalent continuous current.
2. The excitation transient surge due to the breaker
being on the transformer primary side must be al-
lowed for.
MCCB Welder
Weld
workpiece
Control
timer
Supply
Fig. 7.3 Spot-Welder Circuit
The temperature rise of the MCCB and wiring de-
pends on the thermal-equivalent continuous current.
To convert the welder intermittent current into a ther-
mal-equivalent continuous value (Ie), consider the
current waveform (Fig. 7.4); load resistance (R) gives
power dissipation:
W = I12 Rt1
and average heat produced:
t
1
+ t
2
W=t
1
+ t
2
I Rt
1
= I
12
Rβ = R(I
1
β )
2
2
1
where β is the duty factor, defined as
total conduction time
total time
This is equivalent to heating by a continuous current of
I
1
β
.
In the example of Fig. 7.4:
I
e
= I
1
β = 1200 x 0.0625 = 300 (A)
i.e., a continuous current of 300A will produce the
average temperature. In practice, however, the instan-
taneous temperature will fluctuate as shown in Fig.
7.5 and the maximum value (Tm) will be greater than
the average (Te) that would be produced by a con-
tinuous current of 300A. The operation of an MCCB
thermal element depends on the maximum rather than
the average temperature, so it must be selected not
to trip at Tm; in other words, it is necessary to ensure
that its hot-start trip delay is at least as great as the
interval of current flow in the circuit. The rated current
of a “mag-only” MCCB (which does not incorporate a
thermal trip function) can be selected based on the
thermal equivalent current of the load, allowing a
margin of approximately 15% to the calculated value
to accommodate supply-voltage fluctuations, equip-
ment tolerance, etc. Thus:
IMCCB = Ie x 1.15 = 300 x 1.15 = 345 (A)
The MCCB selected becomes the nearest standard
value above 345A.
I
1
1200A
Time
(Duty factor β = 0.0625)
Current
t
1
t
2
(3sec.) (45sec.)
3 +
45
3
Fig. 7.4 Welder Intermittent Current
Time
T
e
T
m
Temperature
Fig. 7.5 Temperature Due to Intermittent Current
For practical considerations, rather than basing
selection on welding conditions, the MCCB should be
selected to accommodate the maximum possible duty,
based on the capacity and specifications of the welder.
If the welder rated capacity, voltage and duty fac-
tor in Fig. 7.3 are 85kVA, 200V and 50% respectively,
the thermal-equivalent continuous current (Ie) be-
=
=
81
comes:
rated voltage
ra
t
e
d
capac
it
y
I
e
= x duty factor
=200
85 + 10
3
x 0.5 = 300A
Hence, the MCCB rated current becomes:
IMCCB = Ie x 1.15 = 300 x 1.15 = 345A
(i.e., the next higher standard value).
The relationship between the duty factor, which
does not exceed the working limitations, and the maxi-
mum permissible input Iβ at the above duty factor is:
β
I
e
I =β
300
=
β
If the total period is taken as 60 seconds and the
duty factor is converted into the actual period during
which current flows, the above relationship can be
expressed graphically as in Fig. 7.6. Thus, although
the thermal equivalent current is 300A, the maximum
permissible input current for a duty factor of 50% (30
seconds current flow) is 425A. For a duty factor of
6.25% (3.75 sec current flow) it is 1200A. Even if the
secondary circuit of the welder were short circuited,
however, the resultant primary current would only in-
crease by about 30% over the standard maximum
welding current. If this is 400kVA, the maximum pri-
mary current Iβmax is:
primary voltage
standard maximum input
I
max
= x 1.3
200
400 x 10
3
x 1.3 = 2600A=
β
Hence the maximum input current Iβ should be re-
stricted to 2600A.
The 75% hot-start characteristic of the 350A Type
NF400-SP breaker is shown by the broken line in Fig.
7.6, and the temperature-rise characteristics up to the
upper limit of the welder, by the solid line. To ensure
protection of the welder from burnout, the delay-trip
characteristic is selected at higher than the solid line;
however, to establish MCCB protection criteria, it is
necessary to look at each welder individually.
Operating time (sec)
30
3.75
0.6
425
Primary input current (A)
Type NF400-SP·350A 75%
hot start
10"
2"
300026001200
Fig. 7.6 Welder Temperature Rise and MCCB Trip Curve
7.4.2 MCCB Instantaneous Trip and Trans-
former Excitation Surge
When a welding-transformer primary circuit is closed,
depending upon the phase angle at the instant of clo-
sure, a transient surge current will flow, due to the
super-imposed DC component and the saturation of
the transformer core.
In order to prevent spurious tripping of protective
devices resulting from such surges, and also to main-
tain constant welding conditions, almost all welders
currently available are provided with a synchronized
switch-on function, with or without wave-peak con-
trol.
With synchronized switch-on, the measured ratio
between the RMS value of the primary current under
normal conditions and the maximum peak transient
current ranges from √
2 ~ 2.
For nonsynchronized soft-starting-type welders the
measured ratio is a maximum of 4.
Maximum instantaneous transient surge excitation
currents for various starting methods are as follows:
Synchronized switch-on welders with wave peak con-
trol:
Imax = 2 x I max
β
Synchronized switch-on welders without wave peak
control:
Imax = 2 x Iβmax
Nonsynchronized switch-on welders with soft start:
Imax = 4 x Iβmax
Nonsynchronized switch-on welders without soft start:
Imax = 20 x Iβmax
If synchronized switch-on is employed, the tran-
sient surge excitation currents are relatively consis-
tent, so that the relationship Imax = 2 Iβmax is suffi-
cient.
For a synchronized switch-on type welder of maxi-
mum primary input (Iβmax) = 2600A
Imax = 2 x Iβmax = 2 x 2600 = 5200A
Since MCCB instantaneous trip currents are speci-
fied in terms of RMS value, Iinst is as follows:
2
Imax
Iinst = = 3680A
2
5200
=
The MCCB should be selected so that Iinst is smaller
than the lower tolerance limit, of the instantaneous
trip current.
7.4.3 Arc Welders
An arc welder is an intermittent load specified. The
MCCB rating can by selected by converting the load
current into thermal-equivalent continuous current. If
this is taken as the rated current, however, the cur-
rent duration per cycle will become relatively long, with
the attendant danger of thermal tripping of the MCCB.
In the total period of 10 minutes, if the duty factor is
50%, a 141% overload exists for 5 minutes; if the duty
factor is 40%, a 158% overload exists for 4 minutes;
and if the duty factor is 20%, a 224% overload exists
82
for 2 minutes. Thus:
E
1.2 x P x 10
3
I
MCCB
≥
where 1.2: Allowance for random variations in
arc-welder current, and supply-volt-
age fluctuations
P: Welder rated capacity (kVA)
E: Supply voltage (V)
The switching transient in the arc welder is mea-
sured as 8~9 times the primary current. Consequently,
using 1.2 allowance, it is necessary to select instan-
taneous-trip characteristics such that the MCCB does
not trip with a current of 11 times the primary current.
7.5 MCCBs for Transformer-Primary Use
Transformer excitation surge current may possibly
exceed 10 times rated current, with a danger of nui-
sance tripping of the MCCB. The excitation surge
current will vary depending upon the supply phase
angle at the time of switching, and also on the level of
core residual magnetism. The maximum is as shown
for switching-point P in Fig. 7.7. During the half cycle
following switch-on the core flux will reach the sum of
the residual flux fr, plus the switching-surge flux 2fm.
The total, 2fm +fr, represents an excitation current in
excess of the saturation value. The decay-time con-
stant of this tends to be larger for larger transformer
capacities. Table 7.2 shows typical values of excita-
tion surge current, but as these do not take circuit
impedance into account, the actual values will be
larger. If both the primary leakage impedance and cir-
cuit impedance are known, the surge current may be
derived by considering the transformer as an air core
reactor; otherwise the values in Table 7.2 should be
used. This table gives maximum values, however, that
are based on the application of rated voltages to rated
taps; it should be noted that supply overvoltage will
result in even larger surges.
Since it is the instantaneous-trip function of the
MCCB that responds to the transient current, ther-
mal-magnetic MCCBs, which can more easily be
manufactured to handle high instantaneous-trip cur-
rents, are advantageous over completely electromag-
netic types, where the instantaneous-trip current is a
relatively small multiple of the rated current.
Table 7.2 Transformer Excitation Surge Currents
Capacity
(kVA)
5
10
15
20
30
50
75
100
150
200
300
500
Decay time constant
(Hz)
4
4
4
4
4
5
5
5
6
6
8
9
First 1/2-cycle peak
(multiple)1
37
37
35
35
34
34
29
28
24
22
18
17
Decay time constant
(Hz)
4
4
5
5
6
6
6
6
8
8
9
12
First 1/2-cycle peak
(multiple)1
26
26
26
26
26
23
18
17
14
13
13
11
1ph transformer 3ph transformer
Table 7.3 Transformer Capacities and Primary-Side MCCBs
Tran.
kVA
5
7.5
10
15
20
30
50
75
100
150
200
300
500
3 phase 400V
NF30-SP ( 30)
NF50-SP ( 40)
NF50-SP ( 50)
NF100-SP ( 50)
NF100-SP ( 60)
NF100-SP ( 100)
NF250-SP ( 150)
NF250-SP ( 175)
NF250-SP ( 225)
NF400-SP ( 300)
NF400-SP ( 350)
NF630-SP ( 600)
NF1000-SS ( 900)
MCCB Type (rated current (A))
1 phase 230V
NF100-SP ( 75)
NF100-SP ( 100)
NF250-SP ( 150)
NF250-SP ( 200)
NF400-SP ( 300)
NF400-SP ( 400)
NF630-SEP ( 600)
NF1000-SS ( 500)
NF1000-SS ( 500)
NF1000-SS ( 800)
NFE2000-S (1200)
NFE2000-S (1500)
—
1 phase 400V
NF100-SP ( 40)
NF100-SP ( 60)
NF100-SP ( 75)
NF250-SP ( 125)
NF250-SP ( 150)
NF250-SP ( 225)
NF400-SP ( 400)
NF630-SP ( 500)
NF630-SP ( 630)
NF1000-SS ( 500)
NF1000-SS ( 600)
NF1000-SS ( 900)
NFE2000-S (1400)
3 phase 230V
NF50-SP ( 50)
NF100-SP ( 40)
NF100-SP ( 60)
NF100-SP ( 100)
NF250-SP ( 125)
NF250-SP ( 175)
NF400-SP ( 250)
NF400-SP ( 300)
NF400-SP ( 400)
NF630-SP ( 500)
NF630-SP ( 600)
NF1000-SS ( 900)
NF1600-SS (1400)
Note: 1 “Multiple” means the first 1/2-cycle peak as a multiple of the rated-current peak.
83
Core saturation
flux
φ
r
PNormal flux
Transient flux
Surge current
Voltage
2φ
m
φ
R
Fig. 7.7 Excitation Surge Effects
In MC CB selection for 400V, 50kVA transformer-
primary used, rated RMS current is:
3 x Voltage (V)
Capacity (kVA) x 10
3
I
= = 72.2A
3 x 400
50 x 10
3
=
From Table 7.2, the peak value of the excitation surge
current Iφ is 23 times that of the rated current, hence:
Iφ =23 x 2 I = 23 x 2 x 72.2A = 2348A
Thus the MCCB selected should have instantaneous
trip current of no less than 2348A. The Type NF250-
SP 150A MCCB, with:
I
inst
= 2 x 150 x 11.2 = 2376A
satisfies the above condition. Thus the 3-pole version
of this type is suitable for this application.
Examples of MCCBs selected in this way are shown
in Table 7.3; it is necessary to confirm that the short-
circuit capacities of the breakers given are adequate
for the possible primary-side short-circuit current in
each case.
7.6 MCCBs for Use in Capacitor (PF Cor-
rection) Circuits
The major surge tendency results from circuit open-
ing due to the leading current. If the capacitor circuit
of Fig. 7.8 is opened at time t1 in Fig. 7.8, arc extinc-
tion will occur at time t2, the zero-point of the leading
current (i). Subsequently the supply-side voltage (Vt)
will vary normally, but the load-side voltage (Vc) will
be maintained at the capacitor charge value. The po-
tential difference (Vc-Vt) will appear across the MCCB
contacts and at time t3, approximately 1/2-cycle after
t2, will become about twice the peak value of the sup-
ply voltage (Em). If the MCCB contacts are not suffi-
ciently open, an arc will reappear across the gap, re-
sulting in an oscillatory capacitor discharge (at a fre-
quency determined by the circuit reactance, includ-
ing the capacitor) to an initial peak-to-peak amplitude
of 4Em. When the arc extinguishes, Vc will once again
be maintained at a potential of –Em and the potential
difference across the MCCB contacts will increase
again. This cycle will repeat until the gap between the
contacts becomes too great, and the interruption will
be completed.
Since Mitsubishi MCCBs exhibit extremely rapid
contact separation, repetitive arcing is virtually non-
existent; however, some MCCBs do not make and
break so rapidly, and in such cases, if the load ca-
pacitance is large enough, they will not discharge
quickly, and if the arc extinguishes near the peak of
the reverse-going oscillation voltage, the capacitor
voltage will be maintained in the region of –3Em by
the first restriking of the arc; at the second restrike it
will become 5Em, on the third –7Em, etc., ultimately
leading to breakdown of the capacitor. Thus, rapid
switching is essential in leading power-factor circuits.
In selecting an MCCB, first consider the surge cur-
rent. If the supply voltage is V volts, the capacitor C
farads, the frequency f Hertz and the current Ι amp,
the kVA rating (P) becomes:
For a three-phase system:
1000 P = 3 VI = 2πfCV2
For a single-phase system:
1000 P = VI = 2πfCV
2
V
t
V
c
C
Fig. 7.8 Capacitor Circuit
Vt
Vc
Vc
i
Vc
t1t2
t3
Em
Em
Fig. 7.9 Circuit-Opening Conditions
V
t
V
c
= Em
V
c
= – 3Em
V
c
= – 7E
m
V
c
= 5E
m
Circuit
opening
Fig. 7.10 Accumulative Capacitor Charge
When the switch (Fig. 7.11) is closed, a charge
(q=CV) must be instantaneously supplied to equal the
+
84
instantaneous supply voltage (V), according to the
phase angle at the instant of circuit closure. This
charge results in a large surge current. If the circuit is
closed at the peak (Em) of the supply voltage (V), the
surge current (i), according to transient phenomena
theory, is:
2 E
m
i =t
2L
R
–
ε
C
4L – R
2
2L
sin t
C
4L – R
2
From Fig. 7.12, the maximum value (im) is:
Em
im =
R
–
ε
C
LR
arctan C
C
4L – R2
4L – R2
and appears at time t = t0 where:
2L
t
0
=R
arctan C
C
4L – R
2
4L – R
2
Although V is not constant, τ0 is extremely small, so
that V = Em can be assumed for the transient dura-
tion; similarly, the conduction time can be assumed
as 2τ0. Thus, an MCCB for use in a capacitive circuit
must have an instantaneous-trip current of greater
than im x 2τ0.
Example: MCCB selection for a 3-phase 230V 50Hz
150 kVA capacitor circuit.
From Table 7.4, C = 0.9026 x 10–2 (F) and I =
377(A).
The values of R and L in the circuit must be esti-
mated, and for this purpose it is assumed that the
short-circuit current is approximately 100 times the
circuit capacity – i.e., 50,000A.
Z = R
2
+ (2πfL)
2
∴ 50,000 = 3 Z
V
thus: Z = = 2.66 x 10
–3
3 x 50,000
230
since: E
m
=
obtained from their respective formulas as,
V = 188, i
m
and τ
0
can be
3
2
and assuming:
then: 2πfL = 2.60 x 10
–3
Ω
thus: R = 5.21 x 10
–4
Ω L = 8.29 x 10
–6
(H)
= 5
R
2πfL
im =6200A
τ0 = 4.27 x 10–4 (sec).
Since current-flow duration is approximately 2τ0,
an MCCB is selected with a latching time of 0.001
seconds at 6200A. The Type NF630-SP is suitable,
having a latching time of 0.0029 seconds at 10,000A.
Even with a shorter latching time, tripping is unlikely
under the application of the above current, but selec-
tion of an MCCB with an instantaneous-trip current of
greater than
M2
6200
= 4400A is recommended for an
adequate safety margin. Such an MCCB will be rated
at 600A. Accordingly, in this example the Type NF630-
SP, rated at 600A, is selected. Table 7.4 is a basis for
selection, but since, in cases where the short-circuit
capacity of the circuit is considerably higher than that
of the MCCB, spurious tripping due to the switching
surge may occur, it is also necessary to make calcu-
lations along the lines of the above example.
EmVc
iL R
C
Fig. 7.11 PF Correction Capacitor
V
c
i
i
m
τ
o
FIg. 7.12 Currents and Voltages
7.7 MCCBs for Thyristor Circuits
Both overcurrent and overvoltage protection must be
provided for these elements. MCCBs can be used
effectively for overcurrent, although application de-
mands vary widely, and selection must be made care-
fully in each case. Overvoltage protection must be
provided separately; devices currently in use include
lightning arresters, dischargers, RC filters and oth-
ers.
1. MCCB Rated Currents
A primary factor determining the rated current of the
MCCB to be used is the question of AC-side or DC-
side installation. AC-side installation permits a lower
rating, which is a considerable advantage. Fig. 7.13
shows both AC and DC installation (MCCBs 1 and 2);
Table 7.5 gives a selection of circuit formats and cur-
rent configurations; using this table it is possible to
determine the MCCB rating for either MCCB 1 or 2,
as required. The current curve of the thyristor (aver-
age current is usually given) and the tripping curve of
the MCCB should be rechecked to ensure that there
is no possibility of overlap.
When an overcurrent is due to a fault in the load,
causing a danger of thermal destruction of the circuit
elements, either AC or DC protection is adequate,
provided the parameters are properly chosen. When
85
Table 7.4 MCCB Selection for Circuits with PF-Correction
a) 230V, 50Hz Circuit
Capacitor rating
kVA
5
10
15
20
25
30
40
50
75
100
150
200
300
400
µF
301
602
903
1203
1504
1805
2407
3009
4513
6017
9026
12034
18052
24069
Single-phase circuit
Capacitor
rated
current
(A)
21.7
43.5
65.2
87.0
108.7
130.4
173.9
217.4
326.1
434.8
652.2
869.6
1304.3
1739.1
MCCB
rated
current
(A)
40
75
100
125
175
200
250
350
500
700
1000
1400
2000
2500
Three-phase circuit
Capacitor
rated
current
(A)
12.6
25.1
37.7
50.2
62.8
75.3
100.4
125.5
188.3
251.0
376.5
502.0
753.1
1004.1
MCCB
rated
current
(A)
20
40
60
75
100
125
150
200
300
400
600
800
1200
1500
b) 230V, 60Hz Circuit
Capacitor rating
kVA
5
10
15
20
25
30
40
50
75
100
150
200
300
400
µF
251
501
752
1003
1254
1504
2006
2507
3761
5014
7522
10029
15043
20057
Single-phase circuit
Capacitor
rated
current
(A)
21.7
43.5
65.2
87.0
108.7
130.4
173.9
217.4
326.1
434.8
652.2
869.6
1304.3
1739.1
MCCB
rated
current
(A)
40
75
100
125
175
200
250
350
500
700
1000
1400
2000
2500
Three-phase circuit
Capacitor
rated
current
(A)
12.6
25.1
37.7
50.2
62.8
75.3
100.4
125.5
188.3
251.0
376.5
502.0
753.1
1004.1
MCCB
rated
current
(A)
20
40
60
75
100
125
150
200
300
400
600
800
1200
1500
Capacitor rating
kVA
5
10
15
20
25
30
40
50
75
100
150
200
300
400
µF
99
199
298
398
497
597
796
995
1492
1989
2984
3979
5968
7958
Single-phase circuit
Capacitor
rated
current
(A)
12.5
25.0
37.5
50.0
62.5
75.0
100.0
125.0
187.5
250.0
375.0
500.0
750.0
1000.0
MCCB
rated
current
(A)
20
40
60
75
100
125
150
200
300
400
600
800
1200
1500
Three-phase circuit
Capacitor
rated
current
(A)
7.2
14.4
21.7
28.9
36.1
43.3
57.7
72.2
108.3
144.3
216.5
288.7
433.0
577.4
MCCB
rated
current
(A)
15
30
40
50
60
75
100
125
175
225
350
500
700
900
c) 400V, 50Hz Circuit
Basically, overcurrent leads to excessive tempera-
ture rise of the thyristor junction, resulting in loss of
the control function, and thermal destruction. A fault,
therefore, must be interrupted as quickly as possible,
before the junction temperature rises above its speci-
fied limit. In the overcurrent region, designated on the
current-surge withstand curves of the circuit element,
the element can usually withstand the surge for at
least one cycle. The current-surge withstand, gener-
ally specified as a peak value, must be converted to
RMS, to select a suitable MCCB.
An overload of short-circuit proportion, either ex-
ternal or in a bridge-circuit thyristor element, necessi-
d) 400V, 60Hz Circuit
Capacitor rating
kVA
5
10
15
20
25
30
40
50
75
100
150
200
300
400
µF
83
166
249
332
414
497
663
829
1243
1658
2487
3316
4974
6631
Single-phase circuit
Capacitor
rated
current
(A)
12.5
25.0
37.5
50.0
62.5
75.0
100.0
125.0
187.5
250.0
375.0
500.0
750.0
1000.0
MCCB
rated
current
(A)
20
40
60
75
100
125
150
200
300
400
600
800
1200
1500
Three-phase circuit
Capacitor
rated
current
(A)
7.2
14.4
21.7
28.9
36.1
43.3
57.7
72.2
108.3
144.3
216.5
288.7
433.0
577.4
MCCB
rated
current
(A)
15
30
40
50
60
75
100
125
175
225
350
500
700
900
the fault is in one of the thyristor elements, resulting
in reverse current, the result is often that other circuit
elements will be destroyed (see Fig. 7.14) if the cir-
cuit is not interrupted immediately. In this case AC-
side protection or protection in series with each ele-
ment is necessary.
2. Tyristor Overcurrent Protection
Total protection of each element is possible in theory,
but in practice overall coordination and the best com-
promise for economy are usually demanded. Where
elements are critical, complex combinations of pro-
tective devices can be employed, at proportionally
higher cost.
Notes: 1. The MCCB rated current should be approx. 150% of the capacitor rated current.
2. The MCCB short-circuit capacity should be adequate for the circuit short-circuit capacity.
86
Note: Load is assumed resistive, with elements conductive through 180°.
Table 7.5 Thyristor Circuits and Current Formats
Fig. 7.13 AC- and DC-side Protectors for Thyristors Fig. 7.14 Fault-Current Flow
Circuit No. I Circuit No. II Circuit No. III Circuit No. IV
Element average current
I
F
(A)
Element RMS current
I
e
(A)
Average DC current
I
D
(A)
RMS current
I
B
(A)
RMS current
I
B
(A)
Current
waveform
Current
waveform
Circuit diagram
Current flow MCCB1MCCB2
π
I
P
2
I
P
2
I
P
2
I
P
π
I
P
π
I
P
π
I
P
6+
(6 0.552 I
P
)
I
P
14π
M3
3+
(6 2.45 I
F
)I
F
π12π
M3
3+
(6 0.817 I
D
)I
D
1
3
π2π
M3
I
F
or
2I
F
2I
F
3I
F
2
πI
F
2
πI
D
or
2
πI
F
4
πI
D
or
M2
πI
F
(6 2.22 I
F
)
2M2
πI
D
(6 1.11 I
D
)
or
2+I
F
6 3I
F
π14π
3M3
2+I
D
6 I
D
1
3
π4π
3M3
or
I
e
2
πI
D
or
M2
πI
F
2M2
πI
D
or
M2
πI
F
2M2
πI
D
or
Load
MCCB1
MCCB1
MCCB2
Load
MCCB1
MCCB2
Load
MCCB1
MCCB2
Load
I
P
I
P
I
P
I
P
I
P
I
P
I
P
I
P
Load
MCCB1
MCCB2
Load
Fault
element
87
protection (MCCB1, Fig. 7.15) is presented, but the
DC-protection case (MCCB2) can be plotted in the
same way.
Region 2 in Fig. 7.17 is the area of overcurrent for
which protection is effected by the MCCB. For pro-
tection of region 1, an overload relay is effective, and
for region 2, inductance L must be relied on to limit
the fault-current rise rate, or a high-speed current-lim-
iting fuse must be used. Practical considerations, in-
cluding economy and the actual likelihood of faults in
the regions concerned, may dictate the omission of
the protective devices for regions 1 and 3, in many
cases. The lower the instantaneous-trip setting of the
MCCB, the wider the region 2 coverage becomes.
MCCB2
MCCB1
L
Smoothing inductance
R
E
Short
circuit
Load
Fig. 7.15 Thyristor Short Circuit
MCCB
Short-circuit current
Trip current
q
Arc voltage
Circuit voltage
t
1
t
3
t
2
t
4
t
T
t
1
: Time to MCCB latching
t
2
: MCCB opening time
t
3
: Time from contact parting to
current peak value
t
4
: Arc duration
t
T
: Total interruption time
q : Current-rise rate
Fig. 7.16 Thyristor Short-Circuit Interruption
tates rapid interruption of the circuit. Normally, such
interruption takes place within one cycle; thus, from
the point of view of element thermal destruction, the
time integral of the current squared must be consid-
ered. Quantitatively, the permissible ei2dt of the ele-
ment must be greater than the ei2dt of the MCCB cur-
rent through interruption, converted to apply to the
element. The latter is influenced by the short-circuit
current magnitude, the interruption time, and the cur-
rent-limiting capability of the MCCB.
It is important to note that the MCCB interruption
time will be considerably influenced by the short-cir-
cuit current rise rate, di/dt, on the load side. In the
short circuit of Figs. 7.15 and 7.16, the current is:
i = (1 – ε )
R
E
–t
L
R
and the current rise rate di/dt is:
( )
t=0
=
dt
di L
E
Thus, the inductance of the line, and the smoothing
inductance significantly affect di/dt. Where the poten-
tial short-circuit current is very large, the inductance
should be increased, to inhibit the rise rate and assist
the MCCB to interrupt the circuit in safe time. This is
illustrated in Fig. 7.17, for MCCB2 of Fig. 7.15.
The MCCB current during total time (tT) is ei2 dt,
which, converted to the ei2 dt applied to the circuit
element, must be within the limit specified. Having
determined the circuit constants, testing is preferable
to calculation for confirmation of this relationship.
Assuming a large current-rise rate, with an AC-side
short-circuit current i = Ipssin ωt, and an MCCB inter-
ruption time of one cycle, the ei2 dt applied to the thy-
ristor is as follows:
1. For circuits I, II and III of Table 7.10:
ei
2
dt = eI
p2
sin
2
ωtdt = I
p2
4f
1
2f
1
0
(A
2
sec)
2. For circuit IV:
ei
2
dt = 2eI
p2
sin
2
ωtdt =
( )
+(A
2
sec
)
f
I
p2
6
14π
3
3f
1
6f
1
where Ip is the peak value of the element current and
f is the supply frequency.
If the ei2 dt of the circuit element is known, the per-
missible ei2dt for the MCCB can be determined, us-
ing the last two equations given above. Provided that
the interruption time is not greater than one cycle, the
MCCB current will be the same as the element cur-
rent for circuits I and II, and twice that for circuits III
and IV. This means that the MCCB ei2dt through the
interruption time should be within twice the permis-
sible ei2dt of the element.
Diodes are generally stronger against overcurrent
than thyristors, and since diodes can handle larger
I2·t, protection is easier.
Fig. 7.17 shows the protection coordination situa-
tion of a selection of devices, plotted together with
the thyristor current-surge withstand curve. AC-side
88
3. Element Breakdown in Thyristor-Leonard Systems
In this system of DC motor control, if power outage or
commutation failure due to a thyristor control-circuit
fault occurs during inversion (while motor regenera-
tive power is being returned to the AC supply), the
DC motor, acting as a generator while coasting, will
be connected to a short-circuit path, as in Fig. 7.18.
For thyristor protection, MCCBs must be placed in the
DC side, as shown.
A Mag-Only MCCB with a tripping current of about
3 times the rated current is employed, either 3- or 4-
pole, series-connected as shown in Fig. 7.20. Since
the element short-circuit current is the same as the
MCCB current, circuit protection is effected provided
that the ei2dt limit for the element is larger than that
for the MCCB interruption duration. This must be es-
tablished by test.
Fig. 7.19 High-Speed Fuses for Thyristor-Circuit Protection Fig. 7.20 Series Connection of MCCB Poles
Fig. 7.18 Ward-Leonard Thyristor Protection
,,
,,
3-Phase Fullwave Rectification
MCCB: Mag-Only
Tripping time
Hrs
Min
Sec
100
2
1
30
20
14
10
8
6
4
2
1
30
20
10
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
125 200 300 400500 600700 1000 1500 2000 3000 4000
Current (% of rating)
Region 1
Region 2
Region 3
Thyristor current-surge withstand
MCCB tripping
High-speed current-limiting fuse
Overcurrent-relay
Fig. 7.17 Thyristor and Protector Operating Curves
M
Short-circuit path in a commutation element failure
Short-circuit path in a power outage
Commutation element failure
AC
supply
High-speed fuses
M
M
M
b) 4-pole MCCB a) 3-pole MCCB
89
Fig. 7.19 shows connection of high-speed fuses
for protection against thyristor breakdown that would
otherwise result in short-circuit flow from the AC sup-
ply side.
4. MCCBs for Lamp Mercury-Lamp Circuits
The ballasts (stabilizers) used in this type of lamp
cover a variety of types and characteristics. For 200V
applications (typical), choke-coil ballasts are used. For
100V applications a leakage-transformer ballast is
employed. Normal ballasts come in low power-factor
versions and high power-factor versions, with correc-
tion capacitors. More sophisticated types include the
constant-power (or constant-output) type, which main-
tains constant lamp current both in starting and nor-
mal running, and flickerless types, which minimize the
flicker attendant on the supply frequency.
In selecting an MCCB where normal (high or low
PF) ballasts are to be used, the determining factor is
the starting current, which is about 170% of the stable
running current. In the cases of constant-power or
flickerless types, the determining factor is the normal
running current, which is higher than the starting cur-
rent. For MCCB selection, the latter types can be re-
garded as lighting and heating general loads, as pre-
viously discussed.
For selection of MCCBs for regular ballasts, the
170% starting current is assumed to endure for a
maximum of 5 minutes. MCCBs of 100A or less frame
size have a tripping value very close to rating for over-
loads of duration of this order, so that the MCCB rat-
ing should be the nearest standard value above 170%
of the stable running current. MCCBs of above 100A
frame size can handle a current of around 120% of
the rating for 5 minutes without tripping; thus the near-
est standard MCCB rating above
1.2
1.7
= 1.4 times the
stable-running current of the lamp load is the suitable
protector.
As an example, consider MCCB selection for 10
units of 100W, 100V, 50Hz general-purpose high
power-factor mercury lamps. The stable-running cur-
rent per lamp is 1.35A. Thus:
1.35 x 10 x 1.7 = 23A, and the selection becomes
NF30-SP, 30A rated.
90
Fig. 7.22 MDU Breaker Circuit Diagram
(without voltage and electric power measurement)
7.8 MDU Breaker
Structure and Motion
The MDU breaker is a circuit breaker equipped with the MDU (Measuring Display Unit) which measures and
digitally displays electric circuit information. Combining the circuit breaker, CT, VT and measuring display unit,
saves space and wiring, allows monitoring of various electric circuits and the energy load conditions.
7.8.1 Measurement
(a) Motion
As shown in Fig. 7.21, the electric current of each phase is transformed by the primary CT and inputted into the
overload relay circuit for an electronic NFB. The electric current is transformed by the secondary CT and sent to
the measuring display unit, MDU. Line voltage is converted to a signal in proportion to the voltage signal by
resistance, transformed by the VT equivalent CT and inputted into the MDU. The MDU measures and displays
by the electric current and voltage signals. Fig. 7.22 shows the internal block diagram of a model without
voltage/electric power measuring functions. The frequency detection circuit provides an electric circuit fre-
quency for measurement calculation.
MDU converts the electric current and volt-
age signals from CT and VT into the volt-
age signal through the I/V conversion sec-
tion. This signal is selected by a multiplexer
and digitized at an A/D conversion section
for digital calculation by a microcomputer.
The CPU performs effective value calcula-
tion, demand calculation, electric power cal-
culation, electric energy accumulation and
harmonic calculation, etc.
The items to be measured are load current,
line voltage, electric power, electric energy
and harmonic current (3rd, 5th, 7th and
ALL). It allows easy confirmation of electric
circuit conditions and precise and efficient Fig. 7.23 MDU Block Diagram
Fig. 7.21 MDU Breaker Circuit Diagram
PAL
Close-open working part
Line side terminal
Trip coil
VT equivalent CT
Open protection circuit
Secondary
CT Overload
relay circuit
Overload signal
MDU circuit
Alarm display
section B/NET
transmission circuit
Fault event
cause signal
Primary
CT
Measuring display
operation section
MDU
power
circuit
MA
MB
FG
Control power
Transmission
line
D
N
S
Load side terminal
PAL
Close-open working part
Line side terminal
Trip coil
Secondary
CT
Overload
relay circuit
Overload signal
MDU circuit
Frequency
detecting
circuit
Alarm display
section B/NET
transmission
circuit
Fault event
cause signal
Primary
CT
Measuring display
operation section
MDU
power
circuit
MA
MB
FG
Control power
Transmission
line
D
N
S
Load side terminal
Open protection circuit
I/V conversion
section
Constant
voltage
circuit
Control
power
Current
input
Voltage
input
Alarm
I/V conversion
section
I/V conversion
section
I/V conversion
section
I/V conversion
section
I/V conversion
section
I/V conversion
section
Input section
Multiplexer
MA
MB
Operation/setup
section
Microcomputer
Segment
LED display
section
Alarm LED
display
section
CPU
A/D
conversion
section
91
(b) Measurement precision
The precision (allowance) of a measurement unit
means the rate of errors against measurement
range expressed as a percentage. The preci-
sion of electric current and voltage, etc. for MDU
is equivalent to JISC1111 and it is the rate of
errors against the rated current and voltage of
measurement expressed as a percentage. Also,
the precision of the electric power and electric
energy is shown as a rate of errors against the
rated current and voltage of measurement.
Table 7.6 Measurement Item List
Fig. 7.24 Example of the NF600-SEP 3P MDU Display
Fig. 7.25 Mounting
(c) External appearance and mounting of MDU
An example of the external appearance of MDU is shown in Fig. 7.24 and Fig. 7.25 showing the mounting
structure.
energy management.Table 7.6 shows all the
items. Sampling for measurement of voltage,
electric current and electric power takes place
once every several seconds, and the measured
values are subject to calculation of the measure-
ment values, such as the present values and
average value, etc. Since the average value and
electric energy are calculated from the sampling
value measured once every several seconds,
care should be taken when there is a breaking
load such as a resistance welder. Electric en-
ergy cannot be used to provide data for con-
tracts or verification.
*1 Confomts to JISC1111.
*2 It is not a power average/supply value obtained by Measurement Method.
*3 B/NET transmission and electric energy accumulated pulse output cannot be mounted simultaneously.
Item
Applicable models
NF600-SEP
NF600-HEP
NF400-SEP
NF400-HEP
Power provided
NF400-SEP
NF400-HEP NF800-SEP
NF800-HEP
Load current of each phase,
precision ±2.5%*
1
Present value, average value, maximum
average value
Line voltage, precision ±2.5%*
1
Present value, average value, maximum
average value
Harmonic load current
3rd, 5th, 7th and ALL
Precision ±2.5%*
1
Present value, maximum value, average
value, maximum average value
Electric power, precision ±2.5%*
1
Present value, average value, maximum
average value
Electric energy accumulated,
precision ±2.5%*
2
Fault event current/fault event cause
Maximum measuring current
Control power
Electric energy accumulated pulse output(option)
B/NET transmission(option)
Alarm(LED Indication)
Maximum measuring voltage
Measuring rated current
Measuring rated voltage
PAL OVER
Load current of each phase, line voltage, electric
power, electric energy, ALL harmonic current, fault
event current/fault event cause
Alarm PAL
Solid straight relay no voltage contact a
DC24V/AC100 •
200V 20mA
Pulse range 0.35 to 0.45sec
Pulse unit 1,10,100,1000,10000, kWh=/Pulse
AC100-240V 50/60Hz DC100V 200V 12VA
••••
••••
•••
•••
••••
•••
400A 400A 600A 800A
440V 440V 440V 440V
800A 800A 1200A 1600A
690V 690V 690V 690V
Measured value display
Outline of main unit mounting Outline of panel mounting
A
m
k
%
A
V
W
Wh
V
W
Wh
RR-S
Display selection Phase
selection ALARMFunction
Measured value
selection
SS-T
TT-R
PRESENT
MAX
DEMAND
TIME
CLEAR
EPAL
Pulse unit
PAL
OVER
EPAL
ECA
Alarm reset
switch
Alarm keep
DEMAND
N
TRIP
LA
PF
DISP
PHASE
MODE
FUNC SET
Function switchMeasured value
selection switch
Phase selection
switch
Display selection
switch Set switch
HARM
Measuring display unit
—
—
—
92
7.8.2 Maintenance function
In the fault event of a circuit breaker trip, the MDU breaker measures the fault event cause and the fault event
current that is load current, and records them in a non-volatile memory device in order to identify the cause of
the fault event and make a prompt recovery. Also, since it records the maximum values of demand current and
hourly electric energy, etc. in a non-volatile memory device, it is useful for understanding the condition of power
consumption. The fault event cause indicates either an overload or a short circuit.
7.8.3 Alarm output function
A circuit breaker monitors various alarm outputs and turns on an alarm LED. The alarms are the PAL, the load
current pre-alarm and OVER, the overload alarm.
7.8.4 Transmission function
The measured data is transmitted through B/NET, MITSUBISHI distribution control network (option). It can
obtain the unit management data for energy saving and automatically collect the electric equipment operation
data for preventive maintenance. Furthermore, electric energy accumulated can output as a pulse output (op-
tion). It enables the direct input into a sequencer realizing labor saving of power consumption control by the
sequencer.
Fig.7.26 Demand Characteristics
An average value is a value close to an average within
the demand time limits. Also, demand time limit ( t0 )
means a period until measuring display value ( I0 )
indicates 95% of input ( I ) when a certain input ( I ) is
continuously turned on. It takes about three times as
long as the time limit ( t0 ) until it indicates 100% of
input ( I ) ( Fig. 7.26 ).
Withstand Voltage and Insulation Resistance Tests
As VT is connected between the poles on the load
side of a circuit breaker, voltage resistance tests be-
tween the electrodes on the load side cannot be con-
ducted (shown as in Table 7.7.) Although an insu-
lation resistance test at DC500V does not result in
damage to the circuit breaker, the insulation resistance
value measured by the test will be low (shown as .)
There is no problem regarding the voltage and insu-
lation resistance tests between the circuit breaker main
circuit and earth.
Table 7.7
Places for Withstand Voltage and Insulation
Resistance Tests
Measured Point/test
Insulation resistance
measurement Withstand voltage
test
Between line part and
earth
State of handle
Between left and
middle poles
Between middle
and right poles
Between left and
right poles
Between middle
and neutral poles
Between left and
middle poles
Between middle
and right poles
Between left and
right poles
Between middle
and neutral poles
Between line and load side
terminal
Load side Line side
Between different poles
ON OFF ON OFF
__
I
0.95I
I0
Measuring
display
value
(Time limit)
t0 Time t
x 100 100% or less
93
7.9 Selection of MCCBs in inverter circuit
7.9.1 Cause of distorted-wave current
Distorted-wave current is caused by factors such as the CVCF device of a computer power unit, various recti-
fiers, induction motor control VVVF device corresponding to more recent energy-saving techniques, etc, wherein
thyristor and transistor are used. Any of these devices generates DC power utilizing the switching function of a
semiconductor and, in addition, transforms the generated DC power into intended AC power. Generally, a large
capacity capacitor is connected on its downstream side from the rectification circuit for smoothing the rectifica-
tion, so that the charged current for the capacitor flows in pulse form into the power circuit. Because voltage is
chopped at high frequency in AC to DC transforming process, load current to which high frequency current was
superimposed by chopping basic frequency flows into the load line. This paragraph describes the VVVF in-
verter, of these devices, which will develop further as main control methods for induction motors currently in
broad use in various fields . Fig. 7.27 illustrates an example of MCCBs application to inverter circuit. Two
control methods of PAM (Pulse Amplitude Modulation) and PWM (Pulse Wide Modulation) are available for the
VVVF inverter and generating higher harmonic wave components differs depending on the difference between
the control methods. As seen from Tables 7.9 and 7.10, this harmonic wave component of input current can be
made smaller (improved) by inputting DC reactor (DCL) or AC reactor (ACL). Further, in the case of the output
current waveform in Fig. 7.29, the PWM generates higher harmonic wave components than that of the PAM.
This table is subject to the current which meets the
following requirements.
Fig.7.27 Example of MCCBs Application to Inverter Circuit
Notes: 1. The characteristics of perfect solenoid type MCCBs vary significantly depending on wave distortion.
Therefore, use of thermal acting solenoid type MCCBs is recommended.
2. NF2000-S, NF2500-S, NF3200-S, NF4000-S
3. NFE2000-S, NFE3000-S, NFE4000-S
Table 7.8 Reduction Rate
q
Distortion percent
=
Real value of total harmonic
wave component
Real value of basic frequency
w Peak factor = Peak value
Real value 3 or less
e Higher harmonic wave components are mainly No.7 or a lower
harmonic wave.
MCCBs tripping system
Thermalacting solenoid type (bimetal system) 1.4
2
1.4
1.4
2
(Note 2) Thermal acting solenoid type (CT system)
(Note 1) Perfect solenoid type
Electronic type (Real value detection)
(Note 3) Electronic type (Peak value detection)
Reduction
rate K
7.9.2 Selection of MCCBs
MCCBs characteristic variations and temperature rises dependent on distortion of the current wave must be
considered when selecting MCCBs for application to an inverter circuit (power circuit). The relation of rated
current INFB to load current I of MCCBs is selected as follows from the MCCBs tripping system.
Thermal acting solenoid type (bimetal system) and electronic type (real value detection) are both real current
detection systems which enable exact overload protection even under distorted-wave current. Due to the above
explanation, it is advantageous to select real current detection type MCCBs.
I
NFB
K x I
NFB
M
Inverter
Induction motor
94
High harmonic
wave degree
High harmonic wave current content (%)
P W M
No ACL (Standard)
Basic
2
3
4
5
6
7
8
9
10
11
12
13
_
_
_
_
_
_
_
3.7
81.6
49.6
27.4
7.6
6.7
_
_
_
_
_
_
_
2.5
83.6
48.3
23.7
6.2
4.7
_
_
_
_
_
_
_
_
97.0
21.9
7.1
3.9
2.8
_
_
_
_
_
_
_
_
97.2
21.7
7.0
3.7
2.6
With power factor modifying ACL With power factor modifying ACL
With standard ACL
P A M
Power factor = (DC voltage x DC) /( 3 x AC effective voltage x AC effective current)
Waveform factor = (Effective value) /(Mean value)
Peak factor = (Max value) /(Effective value)
Circuit
with ACL
Large ACL Small
With
DCL
Input current
Power factor
Below 58.7
58.7%
58.7–83.5%
83.5%
83.5–95.3%
95.3% 1.23 1.28
Above 1.99
1.99
1.99–1.27
1.27
1.27–1.23
Above 2.16
2.16
2.16–1.71
1.71
1.71–1.28
Waveform factor Peak factor Waveform
(half wave portion)
t
I
ACL
VE
d
DCL
VE
d
Table 7.9 Data of High Harmonic Wave Current Content in Inverter Power Circuit (Example)
Table 7.10 Peak Factor of Inverter Input Current
Note: No DCL Output frequency 60Hz , subject to 100% load
Fig.7.28 Inverter Input Current Fig.7.29 Inverter Output Current
(a) PAM system (b) PWM system
(a) PAM system (b) Equal-value PWM system
95
8. ENVIRONMENTAL CHARACTERISTICS
High temperature
Low temperature
High humidity
High altitude
Dirt and dust
Corrosive gas, salt air
Environment Trouble Countermeasures
1. Nuisance tripping
2. Insulation deterioration
1. Condensation and freezing
2. Low-temperature fragility in shipping
(around –40˚C)
1. Insulation resistance loss
2. Corrosion
1. Reduced temperature, otherwise no
problem up to 2,000m
1. Contact discontinuity
2. Impaired mechanism movement
3. Insulation resistance loss
1. Corrosion
1. Reduce load current (derate).
2. Avoid ambients above 60˚C.
1. Install heater for defrosting and drying.
2. Ship tripped, or if not possible, OFF.
1. Use MCCB enclosure such as Type W.
2. Inspect frequently, or install high-
corrosion-resistant MCCBs.
1. See “Low temperature”, above.
1. Use Type I MCCB enclosure.
1. Use Type W MCCB enclosure or install
high-corrosion-resistant MCCBs.
5:
Table 8.1 Abnormal Environments, and Countermeasures
8.1 Atmospheric Environment
Abnormal environments may adversely affect perfor-
mance, service life, insulation and other aspects of
MCCB quality. Where service conditions differ sub-
stantially from the specified range as below, derating
of performance levels may result.
1.
Ambient temperature range
–10˚C~+40˚C (Average
temperature for 24 hours,
however, shall not be
higher than 35˚C.)
2. Relative humidity 85% max. with no dewing
3. Altitude 2,000m max.
4. Ambient No excessive water or oil
vapour, smoke, dust, salt
content, corrosive sub-
stance, vibration, and im-
pact
Expected service life
(MTTF) under the above
conditions is 15 years.
8.1.1 High Temperature Application
To comply with relevant standards, all circuit break-
ers are calibrated at 40˚C. If the circuit breaker is to
be used in an environment where the ambient tem-
perature is likely to exceed 40˚C please apply the de-
rating factor shown in table 8.2.
For example: To select a circuit breaker for use on a
system where the full load current is 70A in an ambi-
ent temperature at 50˚C then from table 8.2
0.9
70A
= 77.8A
Select a circuit breaker with a trip unit adjustable from
80-100A or fixed at 100A.
Table 8.2 MCCB Derating
Ambient Temperature (°C)
50
55
60
Derating factor
0.9
0.8
0.7
96
8.1.2 Low Temperature Application
In conditions where temperatures reach as low as
–5˚C special MCCBs are usually required. Mitsubishi,
however, have tested their standard MCCBs to tem-
peratures as low as –10°C without any detrimental
effects.
For conditions where temperatures drop below
–10˚C special MCCBs must be used.
If standard MCCBs experience a sudden change
from high temperature, high humidity conditions to low
temperature conditions, there is a possibility of ice
forming inside the mechanism. In such conditions we
recommend that some form of heating be made avail-
able to prevent mal-operation.
In conditions of low temperature MCCBs should
be stored in either the tripped or OFF position.
Low Temperature MCCBs
Special low temperature MCCBs are available that
can withstand conditions where temperatures fall to
as low as –40˚C. These special MCCBs are available
in sizes up to 1200A in the standard series and above
50A in the compact series.
8.1.3 High Humidity
In conditions of high humidity the insulation resistance
to earth will be reduced as will the electrical life.
For applications where the relative humidity ex-
ceeds 85% the MCCB must be specially prepared or
special enclosures used. Special preparation includes
plating all metal parts to avoid corrosion and special
painting of insulating parts to avoid the build up of
mildew.
There are two degrees of tropicalisation:
Treatment 1- painting of insulating material to avoid
build up of mildew plus special plating
of metal parts to avoid corrosion.
Treatment 2- painting of insulating material to avoid
build up of mildew only.
8.1.4 Corrosive Atmospheres
In the environment containing much corrosive gas, it
is advisable to use MCCB of added corrosion resis-
tive specifications.
For the breakers of added corrosionproof type,
corrosion-proof plating is applied to the metal parts.
Where concentration of corrosive gas exceeds the
level stated below, it is necessary to use MCCB of
added corrosion resistive type being enclosed in a
water-proof type enclosure or in any enclosure of pro-
tective structure.
Allowable containment for corrosive gas.
H2S 0.01ppm SO20.05ppm
NH31ppm
8.1.5 Affecting of Altitude
When MCCBs are used at altitudes exceeding 2000m
above sea level, the effects of a drop in pressure and
drop in temperature will affect the operating perfor-
mance of the MCCBs. At an altitude of 2200m, the air
pressure will drop to 80% and it drops to 50% at
5500m, however interrupting capacity is unaffected.
The derating factors that are applicable for high alti-
tude applications are shown in table 8.3. (According
to ANSI C 37.29-1970)
Table 8.3 Derating Factors for High Altitude Appli-
cations
Altitude
3000m
4000m
5000m
6000m
Rated current
0.98
0.96
0.94
0.92
Rated voltage
0.91
0.82
0.73
0.65
For example: NF800-SEP on 4000m
1. Voltage
The rated operating voltage is AC690V. You should
derate by 690x0.82=565.8V. It means that you can
use this NF800-SEP up to AC565.8V rated voltage.
2. Current
The rated current is 800A. You should derate by
800x0.96=768A. It means that you can use this
NF800-SEP up to 768A rated current.
8.2 Vibration-Withstand Characteristics
8.2.1 The Condition of Test
1. Installation position and Direction of vibration
• Every vertical and horizontal at vertical installed
(as shown in Fig. 8.1)
2. The position of MCCBs and vibration time
Forty minutes in each position (ON, OFF and TRIP)
3. Vibration criteria
• Frequency 5~100Hz
• Vibration acceleration 2.2g
• Period 10min./cycle
8.2.2 The Result of Test
The samples must show no damage and no change
of operating characteristic (200% release), and must
not be tripped or switched off by the vibration.
Vertical
Wire
connection
Horizontal
Fig. 8.1 Applied Vibration
97
8.3 Shock-Withstand Characteristics
8.3.1 The Condition of Test
1. MCCBs are drop-tested, as described in Fig. 8.2.
The arrows show the drop direction.
2. The samples are set to ON, with no current flow-
ing.
8.3.2 The Result of Test (as Shown in Table 8.4)
The samples must show no physical damage, and
the switched condition must not be changed by the
drop in any of the drop-attitudes tested.
The judgment of failure:
• A case the switched condition changed from ON
to OFF
• A case the switched condition changed from ON
to Trip
• A case the sample shows physical damage
Table 8.4 Shock-Withstand Characteristics of Mitsubishi MCCB
Type
BH-K BH-P, BH-S, BH-PS, BH-D
MB30-CS
MB30-SP MB50-CP MB50-SP
MB100-SP MB225-SP
NF30-SP NF50-HP
NF50-HRP NF60-HP NF100-SP NF100-SEP
NF100-HP NF100-HEP NF160-SP NF160-HP
NF250-SP NF250-SEP NF250-HP NF250-HEP
NF400-SP NF400-SEP NF400-HEP NF400-REP
NF630-SP NF630-SEP NF630-HEP NF630-REP
NF800-SDP NF800-SEP NF800-HEP NF800-REP
NF1000-SS NF1250-SS
NF1600-SS NF2000-S NF2500-S NF3200-S
NF4000-S NFE2000-S NFE3000-S NFE4000-S
NF30-CS
NF50-CP NF60-CP
NF100-CP NF250-CP NF400-CP NF630-CP
NF800-CEP
NF100-UP NF100-RP NF225-UP
NF225-RP NF400-UEP NF630-UEP
NF800-UEP NF1250-UR
No tripped
(G)
15
15
20
20
15
20
20
20
No damage
(G)
50
Series
BH
MB
NF
S
C
U
∗: 1G = 980cm/s
2
Line terminals
Line terminals
Fig. 8.2 Drop-Test Attitudes
98
9.1 Purpose
Japanese and international standards require, in sum-
mary, that an overcurrent protector must be capable
of interrupting the short-circuit current that may flow
at the location of the protector. Thus it is necessary to
establish practical methods for calculating short-cir-
cuit currents for various circuit configurations in low-
voltage systems.
9.2 Definitions
1. % Impedance
The voltage drop resulting from the reference current,
as a percentage of the reference voltage (used for
short-circuit current calculations by the % impedance
method).
reference voltage
voltage drop at capacity load
% impedance = x 100 (%)
(Reference voltage:3-phase – phase voltage)
2. Reference Capacity
The capacity determined from the rated current and
voltage used for computing the % impedance (nor-
mally 1000kVA is used).
3. Per-Unit Impedance
The % impedance expressed as a decimal (used for
short-circuit current calculations by the per-unit
method).
4. Power Supply Short-Circuit Capacity
3-phase supply (MVA) = kl3 x rated voltage (kV) x
short circuit current (kA)
5. Power Supply Impedance
Impedance computed from the short-circuit capacity
of the supply (normally indicated by the electric power
company; if not known, it is defined, together with the
X/R ratio, as 1000MVA and X/R=25 for a 3-phase
supply (from NEMA.AB1).
6. Motor contribution Current
While a motor is rotating it acts as generator; in the
event of a short circuit it contributes to increase the
total short-circuit current. (Motor current contribution
must be included when measuring 3-phase circuit
short-circuit current).
7. Motor Impedance
The internal impedance of a contributing motor. (A
contributing motor equal to the capacity of the trans-
former is assumed to be in the same position as the
transformer, and its % impedance and X/R value are
assumed as 25% and 6 (from NEMA.AB1).
8. Power Supply Overall Impedance
The impedance vector sum of the supply (ZL), the
transformer (ZT) and the motor (ZM).
Overall impedance of 3-phase supply
Z
L
+ Z
T
+ Z
M
(Z
L
+ Z
T
) • Z
M
(Z
s
) = (%Ω)
9. Short-Circuit Current Measurement Locations
In determining the interruption capacity required of
the MCCB, generally, the short-circuit current is cal-
culated from the impedance on the supply side of the
breaker.
Fig. 9.1 represents a summary of Japanese standards.
9.3 Impedances and Equivalent Circuits of
Circuit Components
In computing low-voltage short-circuit current, all im-
pedances from the generator (motor) to the short-cir-
cuit point must be included; also, the current contrib-
uted by the motor operating as a load. The method is
outlined below.
9.3.1 Impedances
1. Power Supply Impedance (ZL)
The impedance from the power supply to the trans-
former-primary terminals can be calculated from the
short-circuit capacity specified by the power company,
if known.
Otherwise it should be defined, together with X/R, as
1000MVA and X/R=25 for a 3-phase supply. Note that
it can be ignored completely if significantly smaller
than the remaining circuit impedance.
2. Transformer Impedance (ZT)
Together with the line impedance, this is the largest
factor in determining the short-circuit current magni-
tude. Transformer impedance is designated as a per-
centage for the transformer capacity; thus it must be
converted into a reference-capacity value (or if using
Ohm’s law, into an ohmic value).
Tables 9.1 show typical impedance values for trans-
formers, which can be used when the transformer
impedance is not known.
3. Motor Contribution Current and Impedance (ZM)
The additional current contributed by one or more
motors must be included, in considering the total 3-
phase short-circuit current. Motor impedance depends
on the type and capacity, etc.; however, for typical
induction motors, % impedance can be taken as 25%
and X/R as 6. The short-circuit current will thus in-
crease according to the motor capacity, and the im-
pedance up to the short-circuit point. The following
assumptions can normally be made.
a. The total current contribution can be considered
as a single motor, positioned at the transformer
location.
b. The total input (VA) of motor contribution can be
considered as equal to the capacity of the trans-
former (even though in practice it is usually larger).
Also, both the power factor and efficiency can be
assumed to be 0.9; thus the resultant motor contri-
bution output is approximately 80% of the trans-
former capacity.
c. The % impedance of the single motor can be con-
sidered as 25% and the X/R as 6.
9. SHORT-CIRCUIT CURRENT CALCULATIONS
99
60Hz
50Hz Reactance(mW/m)
Load
Supply side
MCCB load terminals in the case of bare line (the line
impedance on the MCCB load side may not be added).
MCCB
Load terminal in the case of
insulated line (the line
impedance on the MCCB
load side can be added.)
Fig. 9.1 Short-Circuit Locations for Current Calculations
Table 9.1 Impedances of 3-Phase Transformers
%R
1.81
1.78
1.73
1.61
1.63
1.50
1.25
1.31
1.17
1.23
1.13
Transformer
capacity (kVA)
50
75
100
150
200
300
500
750
1000
1500
2000
Impedance (%)
%X
1.31
1.73
1.74
1.91
2.60
2.82
4.06
4.92
4.94
5.41
5.89
4. Line and Bus-Duct Impedance (ZW, ZB)
Table 9.2 gives unit impedances for various configu-
rations of wiring, and Table 9.3 gives values for duct-
ing.
Since the tables give ohmic values, they must be con-
verted, if the %-impedance method is employed.
5. Other Impedances
Other impedances in the path to the short-circuit point
include such items as CTs, MCCBs, control devices,
and so on. Where known, these are taken into con-
sideration, but generally they are small enough to be
ignored.
9.3.2 Equivalent Circuits
1. Three-Phase
Based on the foregoing assumptions for motors, the
equivalent circuits of Fig. 9.2 can be used for calcu-
lating 3-phase short-circuit current. The motor imped-
ance (ZM) can be considered as shunting the series
string consisting of the supply (ZL) and transformer
(ZT) impedances, by busbars of infinite short-circuit
capacity. When the three impedances are summed,
the total impedance and the resistive and reactive
components are given as:
Cable size
(mm2)Resistance
(mΩ/m) 2-or 3-core
cables
1-core cables
(close-spaced)
1-core cables
(6cm-spaced)
2-or 3-core
cables
1-core cables
(close-spaced)
1-core cables
(6cm-spaced)
1.5
2.5
4.0
6.0
10.0
16.0
25.0
35.0
50.0
70.0
95.0
120.0
150.0
185.0
240.0
300.0
400.0
500.0
630.0
12.10
7.41
4.61
3.08
1.83
1.15
0.727
0.524
0.387
0.268
0.193
0.153
0.124
0.0991
0.0754
0.0601
0.0470
0.0366
0.0283
0.1076
0.1032
0.0992
0.0935
0.0873
0.0799
0.0793
0.0762
0.0760
0.0737
0.0735
0.0720
0.0721
0.0720
0.0716
0.0712
–
–
–
0.1576
0.1496
0.1390
0.1299
0.1211
0.1043
0.1014
0.0964
0.0924
0.0893
0.0867
0.0838
0.0797
0.0806
0.0818
0.0790
0.0777
0.0702
0.0691
0.2963
0.2803
0.2656
0.2527
0.2369
0.2138
0.2000
0.1879
0.1774
0.1669
0.1573
0.1498
0.1427
0.1356
0.1275
0.1195
0.1116
0.1043
0.0964
0.1292
0.1238
0.1191
0.1122
0.1048
0.0959
0.0952
0.0915
0.0912
0.0884
0.0882
0.0864
0.0865
0.0864
0.0859
0.0854
–
–
–
0.1891
0.1796
0.1668
0.1559
0.1453
0.1251
0.1217
0.1157
0.1109
0.1072
0.1040
0.1006
0.0956
0.0967
0.0982
0.0948
0.0932
0.0843
0.0829
0.3555
0.3363
0.3187
0.3033
0.2843
0.2565
0.2400
0.2254
0.2129
0.2001
0.1888
0.1798
0.1712
0.1627
0.1530
0.1434
0.1339
0.1252
0.1157
Notes: 1. Resistance values per IEC 228
2.
Reactance per the equation: L(mH/km) = 0.05 + 0.4605log10D/r(D=core separation, r=conductor radius)
3. Close-spaced reactance values are used.
Table 9.2 Wiring Impedance
Table 9.3 Bus-Duct Impedance
Rated
current (A)
400
600
800
1000
1200
1500
2000
2500
3000
Resistance
(mΩ/m) at 20°C
0.125
0.114
0.0839
0.0637
0.0397
0.0328
0.0244
0.0192
0.0162
Reactance (mΩ/m)
50Hz
0.0250
0.0231
0.0179
0.0139
0.0191
0.0158
0.0118
0.0092
0.0077
60Hz
0.0300
0.0278
0.0215
0.0167
0.0230
0.0190
0.0141
0.0110
0.0092
100
Z
S
= = R
S
+ j X
S
Z
L
+ Z
T
+ Z
M
(Z
L
+ Z
T
) · Z
M
R
S
= (R
L
+ R
T
+ R
M
)
2
+ (X
L
+ X
T
+ X
M
)
2
(R
L
+ R
T
+ R
M
) {R
M
(R
L
+ R
T
) – X
M
(X
L
+ X
T
)}
+ (X
L
+ X
T
+ X
M
) {X
M
(R
L
+ R
T
) + R
M
(X
L
+ X
T
)}
[
X
S
= (R
L
+ R
T
+ R
M
)
2
+ (X
L
+ X
T
+ X
M
)
2
(R
L
+ R
T
+ R
M
) {X
M
(R
L
+ R
T
) + R
M
(X
L
+ X
T
)}
– (X
L
+ X
T
+ X
M
) {R
M
(R
L
+ R
T
) – X
M
(X
L
+ X
T
)}
[
]
]
Thus, when calculating the short-circuit current at
various points in a load system, if the value ZS is first
computed, it is a simple matter to add the various wire
or bus-duct impedances. Table 9.4 gives values of
total supply impedance (ZS), using transformer imped-
ance per Table 9.1, power-supply short-circuit capacity
of 1000MVA, and X/R of 25.
Z
M
Z
B
Z
W
Z
L
L
TB
W
Short-
circuit
point
M
Z
T
Z
B
Z
M
Z
L
Z
W
Z
T
Z
B
Z
W
Z
Z
S
Fig. 9.2 3-Phase Equivalent Circuits
Table 9.4 Total Impedances for 3-Phase Power Supplies
50
75
100
150
200
300
500
750
1000
1500
2000
Impedance based on
1000kVA(%) Ohmic value (mΩ)
Transformer capacity
(kA)
Notes: 1. Total power-supply impedance
ZS = ZL + ZT + ZM
(ZL + ZT)ZM
2. For line voltages (E') other than 200V, multiply the ohmic value by
()
200
2
E'
33.182 +j26.482
21.229 +j22.583
15.473 +j17.109
9.56 +j12.389
6.977 +j12.15
4.306 +j 8.795
2.089 +j 7.27
1.427 +j 5.736
0.969 +j 4.336
0.671 +j 3.142
0.467 +j 2.544
230V
17.553+j14.009
11.230+j11.946
8.185+j 9.051
5.057+j 6.554
3.691+j 6.427
2.278+j 4.653
1.105+j 3.846
0.755+j 3.034
0.513+j 2.294
0.355+j 1.662
0.247+j 1.346
440V
64.240+j51.269
41.099+j43.720
29.956+j33.123
18.508+j23.985
13.507+j23.522
8.336+j17.027
4.044+j14.074
2.763+j11.104
1.876+j 8.394
1.299+j 6.083
0.904+j 4.925
101
I
as
= I
s
· { 1 + 2e e+ 2 1 + } = I
s
· K
3
x
2πR
–x
2πR
–
3
12
1
that is: K
3
= { 1 + 2e e+ 2 1 + }
x
2πR
–x
2πR
–
3
12
1
K3 is the asymmetrical coefficient, derived from the
symmetrical value and the circuit power factor.
3. Peak Value of Asymmetrical Short-Circuit Current
This value (Ip in Fig. 9.3) depends upon the phase
angle at short circuit closing and on the circuit power
factor; it is maximum when θ = 0. It will reach peak
value in each case, ωt =
2
π
+ ϕ after the short circuit
occurrence. It can be computed as before, by means
of the circuit power factor and the symmetrical short-
circuit current.
Ip = Is [1 + sinϕ·e ] = Is · Kp
2
πx
R
–( + ϕ)·
thus: Kp = 2 [1 + sinϕ·e ]
2
πx
R
–( + ϕ)·
Kp, the peak asymmetrical short-circuit current coeffi-
cient, is also known as the closing-capacity coefficient,
since Ip is called the closing capacity. Thus, in each
case, the asymmetrical coefficients can be derived
from the symmetrical values and the circuit power fac-
tor. These coefficients are shown Fig. 9.4.
A
s
A
s
1
/
2
Cycle
I
p
A
d
Fig. 9.3 Short-Circuit Current
9.4 Classification of Short-Circuit Current
A DC current (Fig. 9.3) of magnitude determined by
the voltage phase angle at the instant of short circuit
and-the circuit power factor will be superimposed on
the AC short-circuit current.
This DC component will rapidly decay; however,
where a high-speed circuit-interruption device such
as an MCCB or fuse is employed, the DC component
must be considered. Further, the mechanical stress
of the electric circuit will be affected by the maximum
instantaneous short-circuit current; hence, the short-
circuit current is divided, as below.
1. RMS Symmetrical Short-Circuit Current (Is)
This is the value exclusive of the DC component; it is
As/M2 of Fig. 9.3.
2. RMS Asymmetrical Short-Circuit Current (Ias)
This value includes the DC component. It is defined
as:
2
A
s
I
as
= )
2
+ A
d2
(
Accordingly, when the DC component becomes maxi-
mum (i.e., θ – ϕ = ±
2
π
, where the voltage phase angle
at short circuit is θ, and the circuit power factor is cosϕ),
Ias will also become maximum
2
1
cycle after the short
circuit occurs, as follows:
I
as
= I
s
· 1 + 2e = I
s
· K
1
, that is: K
1
= 1 + 2e
x
2πR
–x
2πR
–
where K1 is the single-phase maximum asymmetrical
coefficient, and Ias can be calculated from the asym-
metrical value and the circuit power factor. In a 3-
phase circuit, since the voltage phase angle at switch-
on differs between phases, Ias will do the same. If the
average of these values is taken
2
1
cycle later, to give
the 3-phase average asymmetrical short-circuit cur-
rent, the following relationship is obtained:
K
p
3.0
2.0
1.0
K
1
K
3
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
20 10 8 76 5 4 3 2.5 2 1.5 1 0.5
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
K
1
: Single-phase maximum
asymmetrical coefficient
K
3
: 3-phase asymmetrical coefficient
K
p
: Closing capacity coefficient
Power factor
R
X
K
p
K
1
K
3
Fig. 9.4 Short-Circuit Current Coefficients
102
9.5 Calculation Procedures
Table 9.5 Necessary Equations
9.5.1 Computation Methods
Regardless of method, the aim is to obtain the total
impedance to the short-circuit point. One of two com-
mon methods is used, depending upon whether a
percentage or ohmic value is required.
1. Percentage Impedance Method
This method is convenient in that the total can be
derived by simply adding the individual impedances,
without the necessity of conversion when a voltage
transformer is used.
Since impedance is not an absolute value, being
based on reference capacity, the reference value must
first be determined. The reference capacity is normally
taken as 1000kVA; thus, the percentage impedance
at the transformer capacity, the percentage imped-
ance derived from the power supply short-circuit ca-
pacity, and also the motor impedance must be con-
verted into values based on 1000kVA (Eqs. 13 and
14). Also, the wiring and bus-duct impedances that
are given in ohmic values must be converted into per-
centage impedances (Eq. 12).
2. Ohmic Method
In calculating short-circuit currents for a number of
points in a system, since the wire and bus-duct im-
pedances will be different in each case, it is conve-
nient to use Ohm’s law, in that if, for example, the
total supply impedance (Zs) is derived as an ohmic
value, the total impedance up to the short-circuit point
can be obtained by simply adding this value to the
wire and bus-duct impedances, which are in series
with the supply. For total 3-phase supply impedance
(Zs), refer to Table 9.4 (which shows calculations of
Zs based on standard transformers) to eliminate
troublesome calculations attendant to the motor im-
pedance being in parallel with Zs.
9.5.2 Calculation Examples
1. 3-phase Circuit
For the short circuit at point S in Fig. 9.5, the equiva-
lent circuit will be as shown in Fig. 9.6. The 3-phase
short-circuit current can be obtained by either the %-
impedance method or Ohm’s law, as given in Table
9.6.
3-phaseImpedance
Ohmic method % impedance method Remarks
I
as
= K
3
· I
s
.......................Eq. 4
Key
I
s
V
Z
I
as
P
%Z
I
B
K
3
3-phase short-circuit current (A, sym)
Line-line voltage (V)
Circuit impedance (1-phase component)
3-phase short-circuit current (A, asym.)
Reference capacity (3-phase component, VA)
% impedance of circuit (single-phase component, %)
Reference current (A)
3-phase asymmetrical coefficient
:
:
:
:
:
:
:
:
•
•
Conversion from percentage value to
ohmic value
Where P is the capacity at which %Z
was derived.
Power supply impedance seen from
primary side
Supply impedance seen from second-
ary side
Conversion from ohmic value to per-
centage value
Eq. 2 is derived from Eqs. 1, 1' and 2'.
Eq. 3 is derived from Eqs. 1 and 1'.
Because Eq. 1 can be obtained from
Eqs. 2 and 12, it can be seen that I
s
of
the % impedance method is not affect-
ed by the selection of the reference ca-
pacity.
The single-phase short-circuit current
in a 3-phase circuit is M3/2 times the 3-
phase short-circuit current. Conse-
quently, a 3-phase circuit can be exam-
ined via the 3-phase short-circuit
current.
Eqs. 9 and 12 are derived from Eqs. 1'
and 2', and Eqs. 3' and 4'.
As the supply impedance is defined as
100% at short circuit capacity, for Eq.
13 conversion to reference capacity is
made.
When the supply short-circuit capacity
is unknown, the impedance is taken as
0.0040+j0.0999 (%) for 3-phase sup-
ply, and 0.0080+j0.1998 (%) for a 1-
phase supply (see Table 9.6).
The motor and transformer impedanc-
es are converted from %Z at their
equipment capacities into %Z at refer-
ence capacity, using Eq. 14.
Eq. 14 for motor impedance becomes
Transformer impedance, motor im-
pedance:
Conversion to %Z at reference capac-
ity
Power-supply impedance:
I
S
= ..................................Eq. 1
M3 · Z
V
Z = · %Z x 10
–2
Ω........................Eq. 9
P
V
2
%Z = · Z x 100%......................Eq. 12
V
2
P
%Z = x 100......Eq. 13
short-circuit capacity
reference capacity
%Z = x
............................................Eq. 14
equipment capacity
reference capacity %Z at equip-
ment capacity
(4.11 + j24.66) x
(For details see Table 9.6.)
equipment capacity
reference capacity
Z = .............Eq. 10
short-circuit capacity
(primary voltages)
2
Z = primary-side
power supply x
impedance
()
2
..........................................Eq. 11
primary voltage
secondary voltages
I
S
= x 100 .................Eq. 2
M3 · V · %Z
P%Z = x 100 ........................Eq. 1'
V/M3
I
B
· Z
P = M3 · V · I
B
...............................Eq. 2'
= x 100 .............................Eq. 3
%Z
I
B
K
3
=
{
1 + 2e e+ 2 1 +
}
x
2πR
–x
2πR
–
3
12
1
•
•
•
•
•
•
•
•
•
•
•
•
103
Table 9.6 Calculation Example: 3-Phase Short-Circuit Current
Fig. 9.6 Equivalent CircuitFig. 9.5 Circuit Configuration
Z
L
= x 100 = 0.1 (%)
1000 x 10
6
1000 x 10
3
Z
T
= (1.23 + j5.41) x
= 0.82 + j3.607 (%)
1500 x 10
3
1000 x 10
3
Z
M
= (4.11 + j24.66) x
= 3.42 + j20.55 (%)1500 x 10
3
x 0.8
1000 x 10
3
Z
S
=
= 0.671 + j3.142 (%)
Z
L
+ Z
T
+ Z
M
(Z
L
+ Z
T
)Z
M
Ohmic method% impedance method
Power supply
impedance
Z
L
Transformer
impedance
Z
T
Motor impedance
Z
M
Total power supply
impedance
Z
S
Line impedance
Z
W
Total impedance
Z
3-phase short-circuit
symmetrical current
123I
s
The supply short-circuit capacity, being unknown, is
defined as 1000MVA with X
L
/R
L
= 25.
From Eq. 13, at the 1000kVA reference capacity:
since X
L
/R
L
= 25,
The total motor capacity, being unknown, is assumed
equal to the transformer capacity, with:
%Z
M
= 25(%) X
M
/R
M
= 6
From Eq. 14, at reference capacity, 1000kVA:
From Table 9.1:
Z
T
= 1.23 + j5.41
From Eq. 14, after conversion to reference capacity,
1000kVA:
Z
W
= (0.0601 + j0.079) x 10
–3
x 10 x 100
= 0.310 + j0.408 (%)
440
2
1000 x 10
3
Multiplying the value from Table 9.2 by a wire length
of 10M, and converting to the 1000kVA reference,
from Eq. 12:
Z = Z
S
+ Z
W
= 0.981 + j3.550 = 3.683 (%)
From Eq. 2:
(R and X are calculated, per §9.3.2.)
0.1 = R
L2
+ (25R
L
)
2
= 25.02R
L
Z
L
= R
L
+ jX
L
= 0.0040 + j0.0999 (%)
I
s
=
= 35.622 (A)
x 100
M3 x 440 x3.683
1000 x 10
3
Z
L
= = 0.0436 (Ω)
1000 x 10
6
(6600)
2
Z
L
= (1.741 + j43.525) x
2
( )
6600
440
Z
L
=
x 100 x 10–2 x 103 = 0.1936 (mΩ)
1000 x 10
6
440
2
Z
T
= x (1.23 + j5.41) x 10
–2
(Ω)
= 1.2906 + j6.9825 (mΩ)
1500 x 10
3
440
2
Z
M
= x (4.11 + j24.66) x 10
–2
(Ω)
= 6.6294 + j39.7847 (mΩ)
1500 x 10
3
x 0.8
440
2
Z
S
=
= 1.299 + j6.083 (mΩ)
Z
L
+ Z
T
+ Z
M
(Z
L
+ Z
T
)Z
M
The supply short-circuit capacity, being unknown, is
defined as 1000MVA with X
L
/R
L
= 25.
From Eq. 10, the supply impedance seen from the
primary sicde:
and since X
L
/R
L
= 25: Z
L
= 1.741 + j43.525 (mΩ)
From Eq. 11, supply impedance converted to the
secondary side is:
and since
X
L
/R
L
= 25, Z
L
= 0.0069 + j0.1721 (mΩ)
Note: The supply ohmic impedance can more simply
be derived: since it is 100% at short-circuit ca-
pacity, Z
L
is obtained from Eq. 9, after percent-
age to ohmic conversion:
The total motor capacity, being unknown, is assumed
equal to the transformer capacity, with:
%Z
M
= 25(%) X
M
/R
M
= 6 Z
M
= 4.11 + j24.66
Z
M
= 4.11 + j24.66 (%)
From Eq. 9, after percentage to ohmic conversion:
Z
W
= (0.0601 + j0.079) x 10
= 0.601 + j0.79 (mΩ)
Multiplying the value from Table 9.2 by a wire length
of 10M.
Z = Z
S
+ Z
W
= 1.900 + j6.873 = 7.1307 (mΩ)
From Eq. 1
(R and X are calculated, per §9.3.2.)
= 0.00773 + j0.1934 (mΩ)
From Table 9.1:
Z
T
= 1.23 + j5.41 (%)
From Eq. 9, after percentage to ohmic conversion.
I
s
=
= 35.622 (A)
M3 x 7.1307x10
–3
440
Short-circuit
point S
3ph 50Hz
6.6kV/440V 1500kVA
10m
Wire
300mm
2
M
Short-circuit
point S
Z
L
Z
M
Z
W
Z
T
MOULDED CASE CIRCUIT BREAKERS
HEAD OFFICE: MITSUBISHI DENKI BLDG., MARUNOUCHI, TOKYO 100-8310. TELEX: J24532 CABLE: MELCO TOKYO
Y-0525-C 9909 (ROD) Printed in Japan
Made from recycled paper
New publication, effective DEC. 1998
Specifications subject to change without notice.
Be sure to read the instruction manual fully before using this product.
Safety Tips
:
