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Home Breakers, Fuses & Circuit Protection Molded Case Circuit Breakers Square D Molded Case Circuit Breakers Square D Molded Case M Frame Circuit Breakers

Molded Case Circuit Breakers (M Frame)

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Square D by Schneider Electric’s PowerPact Multistandard circuit breakers are equipped with dual-break rotating contacts that reduce the amount of peak current during a short-circuit fault. They feature an over-center toggle mechanism providing quick-make, quick-break operation. Internal cross-bars provide common opening and closing of all poles with a single handle. The circuit breaker handle can assume any of three positions, ON, tripped or OFF. The center tripped position provides positive visual indication that the circuit breaker has tripped.

PowerPact M-frame circuit breakers are designed to protect electrical systems from damage caused by short-circuits and overloads. They are equipped with an electronic trip unit which simulates the function of a thermal magnetic trip unit, but provides precise tripping and is not sensitive to temperature changes. They are available in an adjustable amperage trip unit capable of 300 to 800 A settings, or a fixed amperage device rated at 400 or 600 A. PowerPact M-frame circuit breakers come in 2 and 3 pole designs with unit-mount and I-line constructions.

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Schneider Electric MJA36800 Circuit Breaker, PowerPact M, electronic trip, I-line, 800A, 3 poles, 25 kA, 600 V, ABC phasing
Schneider Electric MJA36800 Circuit Breaker, PowerPact M, electronic trip, I-line, 800A, 3 poles, 25 kA, 600 V, ABC phasing
$9219.60 $18945.00
Schneider MJA36800 Circuit breaker 800 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 1600-8000 A 14.85 in (377.19 mm 8.96 in (227.58 mm 8.07 in (204.98 mm 600 V AC I-Line connecti
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Schneider Electric MJA36700 Circuit Breaker, PowerPact M, electronic trip, I-line, 700A, 3 poles, 25 kA, 600 V, ABC phasing
Schneider Electric MJA36700 Circuit Breaker, PowerPact M, electronic trip, I-line, 700A, 3 poles, 25 kA, 600 V, ABC phasing
$9219.60 $18945.00
Schneider MJA36700 Circuit breaker 700 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 1400-7000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection lin
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Schneider Electric MJA36600 Circuit Breaker, PowerPact M, electronic trip, I-line, 600A, 3 poles, 25 kA, 600 V, ABC phasing
Schneider Electric MJA36600 Circuit Breaker, PowerPact M, electronic trip, I-line, 600A, 3 poles, 25 kA, 600 V, ABC phasing
$7247.93 $14893.50
Schneider MJA36600 Circuit breaker 600 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 1200-6000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection lin
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Schneider Electric MJA36500 Circuit Breaker, PowerPact M, electronic trip, I-line, 500A, 3 poles, 25 kA, 600 V, ABC phasing
Schneider Electric MJA36500 Circuit Breaker, PowerPact M, electronic trip, I-line, 500A, 3 poles, 25 kA, 600 V, ABC phasing
$7247.93 $14893.50
Schneider MJA36500 Circuit breaker 500 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 1000-5000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection lin
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Schneider Electric MJA36400 Circuit Breaker, PowerPact M, electronic trip, I-line, 400A, 3 poles, 25 kA, 600 V, ABC phasing
Schneider Electric MJA36400 Circuit Breaker, PowerPact M, electronic trip, I-line, 400A, 3 poles, 25 kA, 600 V, ABC phasing
$7247.93 $14893.50
Schneider MJA36400 Circuit breaker 400 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 800-4000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection line
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Schneider Electric MGA36800 Circuit Breaker, PowerPact M, electronic trip, I-line, 800A, 3 poles, 18 kA, 600 V, ABC phasing
Schneider Electric MGA36800 Circuit Breaker, PowerPact M, electronic trip, I-line, 800A, 3 poles, 18 kA, 600 V, ABC phasing
$7743.60 $15912.00
Schneider MGA36800 Circuit breaker 800 A 65 kA 240 V AC, 35 kA 480 V AC, 18 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M G AL800M23K Electronic, basic, ET 1.0, LI 1600-8000 A 14.85 in (377.19 mm 8.96 in (227.58 mm 8.07 in (204.98 mm 600 V AC I-Line connectio
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Schneider Electric MGA36700 Circuit Breaker, PowerPact M, electronic trip, I-line, 700A, 3 poles, 18 kA, 600 V, ABC phasing
Schneider Electric MGA36700 Circuit Breaker, PowerPact M, electronic trip, I-line, 700A, 3 poles, 18 kA, 600 V, ABC phasing
$7743.60 $15912.00
Schneider MGA36700 Circuit breaker 700 A 65 kA 240 V AC, 35 kA 480 V AC, 18 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M G AL800M23K Electronic, basic, ET 1.0, LI 1400-7000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection line
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Schneider Electric MGA36500 Circuit Breaker, PowerPact M, electronic trip, I-line, 500A, 3 poles, 18 kA, 600 V, ABC phasing
Schneider Electric MGA36500 Circuit Breaker, PowerPact M, electronic trip, I-line, 500A, 3 poles, 18 kA, 600 V, ABC phasing
$5962.46 $12252.00
Schneider MGA36500 Circuit breaker 500 A 65 kA 240 V AC, 35 kA 480 V AC, 18 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M G AL800M23K Electronic, basic, ET 1.0, LI 1000-5000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection line
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Schneider Electric MGA36300 Circuit Breaker, PowerPact M, electronic trip, I-line, 300A, 3 poles, 18 kA, 600 V, ABC phasing
Schneider Electric MGA36300 Circuit Breaker, PowerPact M, electronic trip, I-line, 300A, 3 poles, 18 kA, 600 V, ABC phasing
$5962.46 $12252.00
Schneider MGA36300 Circuit breaker 300 A 65 kA 240 V AC, 35 kA 480 V AC, 18 kA 600 V AC 80 % 3P I-Line M-frame CSA, IEC, UL Listed PowerPact M G AL800M23K Electronic, basic, ET 1.0, LI 600-3000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection line,
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Schneider Electric MJA264002 Circuit Breaker, PowerPact M, electronic trip, I-line, 400 Amp, 2 poles, 25 kA, 600 VAC, lugs load end, AC phasing
Schneider Electric MJA264002 Circuit Breaker, PowerPact M, electronic trip, I-line, 400 Amp, 2 poles, 25 kA, 600 VAC, lugs load end, AC phasing
$9036.73 $18569.25
Schneider MJA264002 Circuit breaker 400 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 2P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 800-4000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection lin
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Schneider Electric MJA263002 Circuit Breaker, PowerPact M, electronic trip, I-line, 300 Amp, 2 poles, 25 kA, 600 VAC, lugs load end, AC phasing
Schneider Electric MJA263002 Circuit Breaker, PowerPact M, electronic trip, I-line, 300 Amp, 2 poles, 25 kA, 600 VAC, lugs load end, AC phasing
$9036.73 $18569.25
Schneider MJA263002 Circuit breaker 300 A 100 kA 240 V AC, 65 kA 480 V AC, 25 kA 600 V AC 80 % 2P I-Line M-frame CSA, IEC, UL Listed PowerPact M J AL800M23K Electronic, basic, ET 1.0, LI 600-3000 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection lin
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Schneider Electric MGA264502 Circuit Breaker, PowerPact M, electronic trip, I-line, 450 Amp, 2 poles, 18 kA, 600 VAC, lugs load end, AC phasing
Schneider Electric MGA264502 Circuit Breaker, PowerPact M, electronic trip, I-line, 450 Amp, 2 poles, 18 kA, 600 VAC, lugs load end, AC phasing
$7262.89 $14924.25
Schneider MGA264502 Circuit breaker 450 A 65 kA 240 V AC, 35 kA 480 V AC, 18 kA 600 V AC 80 % 2P I-Line M-frame CSA, IEC, UL Listed PowerPact M G AL800M23K Electronic, basic, ET 1.0, LI 900-4500 A 12.86 in (326.6 mm 0.32 in (8.06 mm 8.27 in (210 mm 600 V AC I-Line connection line
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What is a Circuit Breaker?

There are two different types of technologies that are commonly used in circuit breakers. 

Magnetic Breakers

Magnetic Breakers are designed to react to short circuits or sharp spikes in voltage and current. The more current that passes through the breaker’s electromagnet, the stronger the magnet becomes. When the current exceeds the rating for that particular breaker, the magnetic force becomes strong enough that it will pull the contact back and disconnect it from the other contact, disconnecting power from the device.

Thermal Protection Breakers

Thermal Protection Breakers protect against a sustained overcurrent, or a higher current, for a longer period of time. Thermal protection uses a Bimetal strip that will bend the contacts away from each other to disconnect power. Thermal Magnetic Breakers are the most common type of circuit breakers. They combine magnetic technology to protect against short circuits or sharp spikes and thermal technology that protects against sustained overcurrent for a long period of time.

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