Time vs. Current Trip Curve @ +25°C
Ambient Compensation Table
Overload Trip Times
100%
135%
200%
300%
400%
500%
600%
No Trip
Trip in 1 hour
4.0 - 40.0 Sec.
1.2 - 12.0 Sec.
0.6 - 5.0 Sec.
0.4 - 2.8 Sec.
0.3 - 1.8 Sec.
.1 1 10 100 1000
Time In Seconds
1000
900
800
700
600
500
400
300
200
100
0
Load Current As A Percent
Of Breaker Rating
10,000
135
To use this chart: Divide the breaker rating by the
correction factor to determine the compensated
rating. Calculate the overloads in terms of the
compensated rating to use the published trip curve.
Do not use these devices outside their specified
operating temperature ranges.
Features
• Compact, trip-free, rocker-actuated design.
• 5 to 20 amp ratings.
• Provides circuit protection and power switching in a single unit.
• Available with optional indicator lamp.
• Snaps into the same cutout as many common power switches.
• Various color, marking and termination options.
Electrical Data @ 25°C
Calibration: Will continuously carry 100% of rating.
May trip between 101% and 134%, but must trip at 135% of
rating within one hour at +25°C.
Dielectric Strength: 1,500VAC (60 seconds).
Insulation Resistance: 100 megohms.
Maximum Operating Voltages: 50VDC; 125 or 250VAC, 50/60 Hz. (model
dependent).
Interrupt Capacity: 1,000 amps in accordance with UL standard 1077.
Resettable Overload Capacity: Ten times rated current.
Reset Time: 60 seconds.
Typical Resistance vs. Current Rating @ +25°C
Mechanical/Environmental Data
Operating Temperature Range: 0°C to +60°C.
Termination: .250” (6.35mm) quick connects or solder terminals.
Mounting: Snaps into 1.122 x .531 (28.5 x 13.5) panel cutout.
Approximate Weight: 0.37 oz. (10.5g).
Current Typical Current Typical
Rating Resistance Rating Resistance
in Amps in Ohms in Amps in Ohms
5.0 0.050 10.0 0.025
6.0 0.042 15.0 0.017
7.0 0.036 20.0 0.0125
8.0 0.031
1
Electronics
Dimensions are shown for reference
purposes only.
Dimensions are in inches over
(millimeters) unless otherwise
specified.
Specifications subject to change. Technical support: 1-800-522-6752
http://relays.tycoelectronics.com
W51 Series Thermal Circuit Breakers
Rocker-Actuated Thermal Circuit Breaker/Power Switch with Optional Indicator Lamp
Catalog 1309288
Issued 4-02
Ambient Rating
Temperature Correction
in °C Factor
10 .90
20 .95
25 1.00
30 1.10
40 1.32
50 1.61
60 2.15
.827
(21.0)
.858
(21.8)
1.260
(32.0)
1.232
(31.3)
.315
(8.0)
.394
(10.0)
.598
(15.2)
.25
(6.35)
.504
(12.8)
.394
(10.0)
.354
(9.0)
TYP. .031
(0.8)
TYP.
1.098
(27.9) 1.311
(33.3)
.079
(2.0)
.118
(3.0)
1.122
(28.5)
.531
(13.5)
SUGGESTED
PANEL CUTOUT
Outline Dimensions
Recommended Panel Cutout
Panel Thickness
W51 series circuit breakers accommodate panel thicknesses
from 0.030 in. to 0.118 in. (0.75 mm - 3.0 mm).
Agency Approvals
W51 series is UL 1077 Recognized as Supplementary Protectors, File
E69543, for Canada and the United States.
Users should thoroughly review the technical data before selecting a product part
number. It is recommended that users also sek out the pertinent approvals files of
the agencies/laboratories and review them to ensure the product meets the
requirements for a given application.
.374
(9.5)
.393
(10.0)
.205
(5.2)
.25
(6.35)
.393
(10.0)
.25
(6.35)
.157 X .098
(4.0 x 2.5)
.098 X .157
(2.5 x 4.0)
Case Styles Marking Options
Terminal Types
Special Order -
Solder
Terminal
Angular Button
Design
Contoured Button
Design
For Contoured
Button Design
(Molded)
For Angular Button Design
(Printed)
W51-A121B1-5
W51-A121B1-6
W51-A121B1-7
W51-A121B1-8
W51-A121B1-10
W51-A121B1-15
W51-A121B1-20
W51-A122B1-5
W51-A122B1-6
W51-A122B1-7
W51-A122B1-8
W51-A122B1-10
W51-A122B1-15
W51-A122B1-20
We recommend that our authorized distributors stock the following items for immediate delivery.
2
Electronics
W51 Series Thermal Circuit Breakers
Specifications and availability subject to change without notice.
1309288 – 5M – KRG – XXX – 4/02 Printed in U.S.A.
© 2002 by Tyco Electronics Corporation. All Rights Reserved.
P&B and TYCO are trademarks.
Tyco Electronics Corporation
Harrisburg, PA 17105
Catalog 1309288
Issued 4-02
Ordering Information
ORDERING NOTE: Some options illustrated below are not listed in the “Ordering Information” chart above. Options denoted by “Special” or “Special Order” in their
descriptions are only offered on a special order basis. Other base and button colors and intermediate amp ratings are also available on a special order
basis. All special order items are subject to extended leadtimes and significant minimum order quantities. Your Tyco Electronics sales engineer must
consult with the factory before providing price and availability information regarding items with these options.
Typical Part No. BW51-A121B1-5
1. Designator:
W = Circuit breaker
2. Series Number:
51 = Switchable, Single Pole, Rocker-Actuated Thermal Model
3. Terminals:
A = Quick connect .250” (6.35mm) straight
4. Breaker Style & Base Color:
1 = Angular button design (see drawing below), black base color
B = Countoured button design (see drawing below), black base color
5. Rocker Color:
1 = Amber (translucent)
2 = Red (translucent)
3 = Green (translucent)
4 = White (opaque - for use on non-illuminated models)
5 = Black (opaque - for use on non-illuminated models)
6 = Red (opaque - for use on non-illuminated models)
7 = Gray (opaque - for use on non-illuminated models)
8 = Black (opaque) with red (translucent) indicator (only available on model with contoured button)
9 = Black (opaque) with green (translucent) indicator (only available on model with contoured button)
6. Maximum Operating Voltage (AC):
1 = 125VAC 2 = 250VAC
7. Light:
A = Non-illuminated B = Illuminated
8. Marking option:
0 = No marking 2 = RESET/OFF molded (only available on model with contoured button)
1 = RESET/OFF printed
9. Specify Amp Rating:
5678 101520
Standard –
.250 Quick Connect
Terminal
Standard -
RESET/OFF
Standard -
RESET/OFF
Printed on
Bezel
Standard -
RESET/OFF
Standard -
RESET/OFF
Molded into
bezel
Standard -
No Marking
