3A Breakers | McMaster-Carr

Clear All

	Current Current	Show

	Current Current	Hide

1/20A

	Number of Poles Number of Poles

	Mounting Location Mounting Location

DIN Rail

Panel

Fuse Block

	Frequency Frequency

50Hz

60Hz

	Voltage Voltage

	Specifications Met Specifications Met

	Circuit Breaker Type Circuit Breaker Type

Thermal

Magnetic

	Breakthrough Current Breakthrough Current

	Wire Connection Type Wire Connection Type


Screw-Clamp Terminals	Quick- Disconnect Terminals

	Manual Reset Style Manual Reset Style


Toggle	Push Button

	Maximum Temperature Maximum Temperature

	System of Measurement System of Measurement

Inch

	Width Width

	Depth Depth

2.36"

	Reset Type Reset Type

Manual

	Minimum Temperature Minimum Temperature

-25° F or less

-24° to 0° F

25° F or greater

	Height Height

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

	Depth Behind Panel Depth Behind Panel

2.42"

	Manufacturer Fuse Equivalent Manufacturer Fuse Equivalent

257

ATC

ATO

	For Panel Cutout Diameter For Panel Cutout Diameter

1/4"

	Mount Type Mount Type

Screw

	Environmental Rating Environmental Rating

IP40

View catalog pages (2)

Forward

How can we improve?

15 Products

DIN-Rail Mount AC Branch Circuit Breakers

1 Pole Circuit Breaker

2 Pole Circuit Breaker

3 Pole Circuit Breaker

Use these circuit breakers upstream from small transformers, lighting, and control circuits. They meet UL 489 requirements for branch circuit protection. All are thermal/magnetic—breakers trip when heat is generated by sustained, low-level overload current, but will trip quickly when the magnetic field in the coil senses a high-current short circuit. Mount directly to DIN rail.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

Alarm (sold separately) sends an audible signal when the breaker is tripped.

1 Pole—Toggle Style
Voltage	Frequency, Hz	Breakthrough Current	For DIN Rail Size, mm	Wire Connection Type	Ht.	Wd.	Dp.	Temp. Range, °F	Features	Specifications Met	Current, A		Each
277V AC	50/60	10,000 A @ 277 V AC	35	Screw-Clamp Terminals	4.13"	0.7"	2.36"	-4° to 140°	Time Delay Trip	UL 489, CSA Certified	3	000000	000000
2 Pole—Toggle Style
277V AC/480YV AC	50/60	10,000 A @ 277 V AC 10,000 A @ 480 V AC	35	Screw-Clamp Terminals	4.13"	1.39"	2.36"	-4° to 140°	Time Delay Trip	UL 489, CSA Certified	3	000000	00000
3 Pole—Toggle Style
277V AC/480YV AC	50/60	10,000 A @ 277 V AC 10,000 A @ 480 V AC	35	Screw-Clamp Terminals	4.13"	2.09"	2.36"	-4° to 140°	Time Delay Trip	UL 489, CSA Certified	3	000000	00000

Alarms

Alarm

Current	Includes		Each
0.5 A @ 110 V DC, 2 A @ 250 V AC	Two Sets of Auxillary Contacts	0000000	000000

High-Inrush DIN-Rail Mount AC Branch Circuit Breakers

Able to handle high inrush current caused by equipment startup, use these circuit breakers upstream from motors and larger transformer applications. They meet UL 489 requirements for branch circuit protection. All are thermal/magnetic—breakers trip when heat is generated by sustained, low-level overload current, but will trip quickly when the magnetic field in the coil senses a high-current short circuit. Mount directly to DIN rail.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

Alarm (sold separately) sends an audible signal when the breaker is tripped.

1 Pole

2 Pole

3 Pole

1 Pole—Toggle Style
Voltage	Frequency, Hz	Breakthrough Current	For DIN Rail Size, mm	Wire Connection Type	Ht.	Wd.	Dp.	Temp. Range, °F	Features	Specifications Met	Current, A		Each
277V AC	50/60	10,000 A @ 277 V AC	35	Screw-Clamp Terminals	4.13"	0.7"	2.36"	25° to 100°	Time Delay Trip	UL 489, CSA Certified, IEC European Standards	3	000000	000000
2 Pole—Toggle Style
277V AC/480YV AC	50/60	10,000 A @ 277 V AC 10,000 A @ 480 V AC	35	Screw-Clamp Terminals	4.13"	1.39"	2.36"	25° to 100°	Time Delay Trip	UL 489, CSA Certified, IEC European Standards	3	000000	00000
3 Pole—Toggle Style
277V AC/480YV AC	50/60	10,000 A @ 277 V AC 10,000 A @ 480 V AC	35	Screw-Clamp Terminals	4.13"	2.09"	2.36"	25° to 100°	Time Delay Trip	UL 489, CSA Certified, IEC European Standards	3	000000	00000

Alarms

Current	Includes		Each
0.5 A @ 110 V DC, 2 A @ 250 V AC	Two Sets of Auxillary Contacts	0000000	000000

DIN-Rail Mount AC Equipment Circuit Breakers

These circuit breakers meet UL 1077 requirements for supplemental circuit protection and are designed for use downstream of a branch circuit breaker. Use them with small transformers, lighting, and control circuits. All are thermal/magnetic—breakers trip when heat is generated by sustained, low-level overload current, but will trip quickly when the magnetic field in the coil senses a high-current short circuit. Mount directly to DIN rail.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

Alarm (sold separately) sends an audible signal when the breaker is tripped.

1 Pole

1 Pole—Toggle Style
Voltage	Frequency, Hz	Breakthrough Current	For DIN Rail Size, mm	Wire Connection Type	Ht.	Wd.	Dp.	Temp. Range, °F	Features	Specifications Met	Current, A		Each
277V AC	50/60	5,000 A @ 277 V AC	35	Screw-Clamp Terminals	3.15"	0.7"	2.36"	-40° to 165°	Time Delay Trip	UL 1077, CSA Certified, CE Marked	3	000000	000000

Alarms

Current	Includes		Each
0.5 A @ 110 V DC, 2 A @ 250 V AC	Two Sets of Auxillary Contacts	0000000	000000

High-Inrush DIN-Rail Mount AC Equipment Circuit Breakers

Able to handle high inrush currents caused by equipment startup, these circuit breakers are suitable for motor and larger transformer applications. They meet UL 1077 requirements for supplemental circuit protection and are designed for use downstream of a branch circuit breaker. All are thermal/magnetic—breakers trip when heat is generated by sustained, low-level overload current, but will trip quickly when the magnetic field in the coil senses a high-current short circuit. Mount directly to DIN rail.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

Alarm (sold separately) sends an audible signal when the breaker is tripped.

1 Pole

2 Pole

3 Pole

1 Pole—Toggle Style
Voltage	Frequency, Hz	Breakthrough Current	For DIN Rail Size, mm	Wire Connection Type	Ht.	Wd.	Dp.	Temp. Range, °F	Features	Specifications Met	Current, A		Each
277V AC	50/60	5,000 A @ 277 V AC	35	Screw-Clamp Terminals	3.15"	0.7"	2.36"	25° to 100°	Time Delay Trip	UL 1077, CSA Certified, CE Marked, IEC European Standards	3	000000	000000
2 Pole—Toggle Style
277V AC/480YV AC	50/60	5,000 A @ 277 V AC 5,000 A @ 480 V AC	35	Screw-Clamp Terminals	3.15"	1.4"	2.36"	25° to 100°	Time Delay Trip	UL 1077, CSA Certified, CE Marked, IEC European Standards	3	000000	00000
3 Pole—Toggle Style
277V AC/480YV AC	50/60	5,000 A @ 277 V AC 5,000 A @ 480 V AC	35	Screw-Clamp Terminals	3.15"	2.1"	2.36"	25° to 100°	Time Delay Trip	UL 1077, CSA Certified, CE Marked, IEC European Standards	3	000000	00000

Alarms

Current	Includes		Each
0.5 A @ 110 V DC, 2 A @ 250 V AC	Two Sets of Auxillary Contacts	0000000	000000

Vibration-Resistant Blade-Style DC Circuit Breakers

These circuit breakers resist vibration better than standard low-voltage DC circuit breakers. They protect against overload and short circuits in low-voltage automotive and other electronic applications. Use them to replace type ATC, AT, ATO, and 257 blade-style fuses. All are thermal, so they use the heat generated in overcurrent situations to trip the breaker.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

Push Button Style
Voltage	Breakthrough Current	Mounting Location	Ht.	Wd.	Blade Ht.	Temp. Range, °F	Environmental Rating	Specifications Met	Current, A		Each
48V DC	2,000 A @ 48 V DC	Fuse Block	1.5"	0.87"	0.25"	-40° to 185°	IP40	SAE J553	3	000000	000000

Blade-Style High-Voltage DC Circuit Breakers

Rated to 72V DC, these can handle higher voltages than any other DC circuit breaker we offer. Use these circuit breakers in place of type ATC, AF, ATO, and 257 blade-style fuses to protect against overload and short circuits in low-voltage automotive and electronic applications. All are thermal, so they use the heat generated in overcurrent situations to trip the breaker.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

DIN-rail mount holder is required (sold separately) to mount circuit breakers to DIN-rail.

Push Button Style

Voltage	Breakthrough Current	Mounting Location	Ht.	Wd.	Blade Ht.	Temp. Range, °F	Specifications Met	Current, A		Each
72V DC	2,000 A @ 72 V DC	Fuse Block	2.06"	0.96"	0.25"	0° to 140°	CSA Certified, UL Recognized Component, UL 1077	3	000000	000000

DIN-Rail Mount Holders

For DIN Rail Size, mm	Wire Connection Type		Each
35	Screw-Clamp Terminals	000000	000000

Panel-Mount AC/DC Circuit Breakers

In addition to protecting equipment, these circuit breakers can be used as on/off switches. Able to handle high inrush current found in motor start-ups. They meet UL 1077 requirements for supplemental circuit protection and are designed for use downstream of a branch circuit breaker. All are thermal, so they use the heat generated in overcurrent situations to trip the breaker.

Breakthrough current is the maximum current that the circuit breaker can safely stop in the event of a short circuit.

Toggle Style—Screw-On Mount

Toggle Style

No. of Poles	Voltage	Frequency, Hz	For Panel Cutout Dia.	Dp. Behind Panel	Quick-Disconnect Tab Wd.	Temp. Range, °F	Specifications Met	Current, A		Each
1	250V AC/75V DC	50/60	1/4"	2.42"	0.25"	-20° to 140°	UL Recognized Component	3	000000	000000