40A Breakers | McMaster-Carr

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	Current Current	Show

40A

	Current Current	Hide

	Voltage Voltage

	Number of Poles Number of Poles

	Mounting Location Mounting Location

DIN Rail

Breaker Box

Panel

	Wire Connection Type Wire Connection Type


Screw-Clamp Terminals	Snap On

Screw Terminals

	Manufacturer Manufacturer

Square D

Siemens

Cutler-Hammer

	Manufacturer Series Manufacturer Series

Homeline

	Manual Reset Style Manual Reset Style


Toggle	Push Button

Lever	Push-Pull Button

	Breakthrough Current Breakthrough Current

	Frequency Frequency

50Hz

60Hz

	System of Measurement System of Measurement

Inch

	Width Width

	Circuit Breaker Type Circuit Breaker Type

Thermal

Magnetic

	Specifications Met Specifications Met

CE Marked

CSA

IEC

	Reset Type Reset Type

Manual

	Number of Mounting Holes Number of Mounting Holes

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

DFARS Specialty Metals
COTS-Exempt

	Maximum Temperature Maximum Temperature

	Height Height

	Depth Depth

	For Panel Cutout Diameter For Panel Cutout Diameter

0.49"

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

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14 Products

Square D Load-Center Circuit Breakers

QO Series, 2 Pole

Homeline Series, 1 Pole

Homeline Series, 2 Pole

Match these circuit breakers to Square D breaker boxes or panel boards of the same manufacturer series. 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.

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

For technical drawings and 3-D models, click on a part number.

QO Series
Voltage	Frequency, Hz	Breakthrough Current	Mounting Location	Wire Connection Type	Wd.	Features	Specifications Met	Current, A		Each
2 Pole—Toggle Style
120V AC/240V AC	60	10,000 A @ 120 V AC 10,000 A @ 240 V AC	Breaker Box	Snap On	1 1/2"	Time Delay Trip	UL Listed, UL 489	40	0000000	000000
Homeline Series
1 Pole—Toggle Style
120V AC/240V AC	60	10,000 A @ 120 V AC	Breaker Box	Snap On	1"	Time Delay Trip	UL Listed, UL 489	40	00000000	00000
2 Pole—Toggle Style
120V AC/240V AC	60	10,000 A @ 120 V AC 10,000 A @ 240 V AC	Breaker Box	Snap On	2"	Time Delay Trip	UL Listed, UL 489	40	0000000	00000

Siemens Load-Center Circuit Breakers

2 Pole

Use with Siemens EQ series breaker boxes. These circuit breakers 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.

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

2 Pole—Toggle Style
Voltage	Frequency, Hz	Breakthrough Current	Wire Connection Type	Wd.	Features	Current, A		Each
120V AC/240V AC	60	10,000 A @ 120 V AC 10,000 A @ 240 V AC	Screw-Clamp Terminals	2"	Time Delay Trip	40	000000	000000

Cutler-Hammer Load-Center Circuit Breakers

2 Pole

Install these circuit breakers into Cutler-Hammer CH series breaker boxes. 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.

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

2 Pole—Toggle Style
Voltage	Frequency, Hz	Breakthrough Current	Wire Connection Type	Wd.	Features	Current, A		Each
120V AC/240V AC	60	10,000 A @ 120 V AC 10,000 A @ 240 V AC	Screw-Clamp Terminals	1 1/2"	Time Delay Trip	40	000000	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.

For technical drawings and 3-D models, click on a part number.

3 Pole

3 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/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"	-40° to 165°	Time Delay Trip	UL 1077, CSA Certified, CE Marked	40	000000	0000000

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.

For technical drawings and 3-D models, click on a part number.

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	40	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	40	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	40	000000	000000

Alarms

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

Harsh-Environment DC Circuit Breakers

Built to resist vibration and corrosion in harsh environments. These circuit breakers protect against overload and short circuits in low-voltage automotive and other 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.

Push-pull button and lever style breakers can be used as an on/off switch.

For technical drawings and 3-D models, click on a part number.

Push-Pull Button Style

Number of Poles	Voltage	Breakthrough Current	For Panel Cutout Dia.	Dp. Behind Panel	Mount Type	Mounting Fasteners Included	Wire Connection Type	Temp. Range, °F	Specifications Met	Current, A		Each
1	28V DC	6,000 A @ 28 V DC	0.49"	2.48"	Screw On	Yes	Screw Terminals	-65° to 165°	UL Recognized Component	40	000000	000000

Lever Style

							Mounting Holes
Number of Poles	Voltage	Breakthrough Current	Ht.	Wd.	Dp.	Mount Type	No. of	Dia.	Mounting Fasteners Included	Wire Connection Type	Temp. Range, °F	Specifications Met	Current, A		Each
1	48V DC	5,000 A @ 48 V DC	3.44"	2.32"	1.72"	Screw On	3	0.19"	No	Screw Terminals	-40° to 185°	CE Marked	40	000000	000000

Push Button Style

							Mounting Holes
Number of Poles	Voltage	Breakthrough Current	Ht.	Wd.	Dp.	Mount Type	No. of	Dia.	Mounting Fasteners Included	Wire Connection Type	Temp. Range, °F	Specifications Met	Current, A		Each
1	42V DC	3,000 A @ 42 V DC	2.89"	1.9"	1.44"	Screw On	2	0.25"	No	Screw Terminals	-25° to 180°	CE Marked	40	000000	000000

High-Temperature Panel-Mount AC/DC Circuit Breakers

1 Pole

These magnetic circuit breakers are unaffected by temperature changes so they are suitable for high-temperature environments. They trip when the magnetic field in the coil increases from current overload.

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

For technical drawings and 3-D models, click on a part number.

				For Panel Cutout
Voltage	Frequency, Hz	Breakthrough Current	Temp. Range, °F	Ht.	Wd.	Dp. Behind Panel	Wire Connection Type	Ht.	Wd.	Current, A		Each
1 Pole—Lever Style
250V AC/80V DC	50/60	1,500 A @ 250 V AC 5,000 A @ 80 V DC	-40° to 185°	1.45"	0.76"	2.48"	Screw Terminals	2.5"	0.75"	40	0000000	000000