Molded & Insulated Case Circuit Breakers

While our website showcases a large assortment of our products, it does not reflect the complete inventory of products currently available. For real-time availability and to ensure we can meet your specific needs, please contact our sales team at 1-800-328-1842. New products arrive daily and our knowledgeable staff are happy to assist you in locating the exact item(s) you need.

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC E/O F/M

Square D MP30H1 Masterpact circuit breaker: 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit, LSIG functions, ground fault, auxiliary switches- 10A/6A/3A @ 240/480/600 VAC, .5A/.25A @125/250 VDC, overcurrent trip switch- 10A/240 VAC, LT alarm- .1A/240 VAC, shunt trip- 24 VDC, closing release- 24 VDC, under voltage release- 24 VDC, motor & charged switch- 24/30 VDC, neutral sensor, electrically operated (E/O)- 24/30 VDC, fixed-mount (F/M), neutral sensor, used tested with report.
SKU: MCCB1678

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC E/O F/M

Square D MP30H1 Masterpact circuit breaker; 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit, LSIG functions, ground fault, auxiliary switches- 10A/6A/3A @ 240/480/600 VAC, .5A/.25A @ 125/250 VDC, overcurrent trip switch- 10A/240 VAC, LT Alarm- .1A/240 VAC, shunt trip- 24 VDC, closing release- 24 VDC, under voltage release- 24 VDC, motor charged switch- 24/30 VDC, neutral sensor, electrically operated (E/O)- 24/30 VDC, fixed-mount (F/M), used tested with report.
SKU: MCCB1684

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC E/O F/M

Square D MP30H1 Masterpact circuit breaker; 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit- LSIG functions, ground fault, auxiliary switches- 10A/6A/3A @ 240/480/600 Volt AC, .5A/.25A @125/250 VDC, overcurrent trip switch- 10A/240 VAC, LT Alarm- .1A/240 VAC, shunt trip- 24 VDC, closing release- 24 VDC, under voltage release- 24 VDC, motor charged switch- 24/30 VDC, neutral sensor, electrically operated (E/O)- 24/30 VDC, fixed-mount (F/M), used tested with report.
SKU: MCCB1685

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC E/O F/M

Square D MP30H1 Masterpact circuit breaker; 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit with LSIG functions, ground fault, auxiliary switches- 10A/6A/3A @ 240/480/600 VAC, .5A/.25A @125/250 VDC, overcurrent trip switch- 10A/240 VAC, LT Alarm- .1A/240 VAC, shunt trip- 24 VDC, closing release- 24 VDC, under voltage release- 24 VDC, motor & charged switch- 24/30 VDC, neutral sensor, electrically operated (E/O)- 24/30 VDC, fixed-mount (F/M), neutral sensor, used tested with report.
SKU: MCCB1687

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC E/O F/M

Square D MP30H1 Masterpact circuit breaker; 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit, LSIG functions, ground fault, auxiliary switches- 10A/6A/3A @ 240/480/600 VAC, .5A/.25A @125/250 VDC, overcurrent trip switch- 10A/240 VAC, LT Alarm- .1A/240 VAC, shunt trip- 24 VDC, closing release- 24 VDC, under voltage release- 24 VDC, motor & charged switch- 24/30 VDC, neutral sensor, electrically operated (E/O)- 24/30 VDC, fixed-mount (F/M), neutral sensor, used tested with report.
SKU: MCCB1689

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC E/O F/M

Square D MP30H1 Masterpact circuit breaker; 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit, LSIG functions, ground fault, auxiliary switches- 10A/6A/3A @ 240/480/600 Volt AC, .5A/.25A @125/250 Volt DC, overcurrent trip switch- 10A/240 Volt AC, LT Alarm- .1A/240 Volt AC, shunt trip- 24 Volt DC, closing release- 24 Volt DC, under voltage release- 24 Volt DC, motor charged switch- 24/30 Volt DC, neutral sensor, electrically operated (E/O)- 24/30 Volt DC, fixed-mount (F/M), neutral sensor, used tested with report.
SKU: MCCB1693

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC F/M E/O

Square D MP30H1 Masterpact circuit breaker; 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit cat# 54766, LSIG functions, ground fault, auxiliary switches, LT alarm- 240 VAC, shunt release- 24 VDC, motor operator- 24/30 VDC, closing release- 24 VDC, under voltage release- 24 VDC, overcurrent- 10A/240 VAC, current neutral sensor cat# 685 527 A, fixed-mount (F/M), electrically operated (E/O), used tested with report.
SKU: MCCB1698

Square D Masterpact MP30H1 Circuit Breaker 3000 Amp 600 VAC F/M E/O

Square D MP30H1 Masterpact circuit breaker: 3000 amp, 600 volt AC, 3 pole. With STR 58 U trip unit cat# 54766 with LSG functions, ground fault, auxiliary switches, LT Alarm- 240 VAC, shunt release- 24 VDC, motor operator- 24/30 VDC, closing release- 24 VDC, under voltage release- 24 VDC, overcurrent- 10A/240 VAC, current neutral sensor cat# 685 527 A, fixed-mount (F/M), electrically operated (E/O), used tested with report.
SKU: MCCB1699

Square D MasterPact MP30H1 Circuit Breaker 3000 Amp 600 Volt AC E/O D/O

Square D MasterPact MP30H1 Circuit Breaker; 3000 amp, 600 volt, 3 pole, electrically operated (E/O), draw-out (D/O). With STR 58 U trip unit, LSIG functions, ground fault. Used tested with a report.
SKU: MCCB2135
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Square D MasterPact MP30H1 Circuit Breaker 3000 Amp 600 Volt AC E/O D/O

Square D MasterPact MP30H1 Circuit Breaker; 3000 amp, 600 volt AC, 3 pole, electrically operated (E/O), draw-out (D/O). With STR58U trip unit, LSI functions, 3000 amp rating plug- cat # 54766, auxiliary switches, overcurrent trip switch, LT alarm, shunt trip, closing release, & motor and "charged" switch. Used tested with report.
SKU: MCCB2239
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Square D MasterPact NW20N Circuit Breaker 2000 Amp 600 Volt AC E/O D/O

Square D MasterPact NW20N Circuit Breaker; cat# WL1FF33A9SXXXXXXX, 2000 Amp, 600 volt AC, 3 pole. With micrologic 5.0A trip unit, LSI functions, electrically operated (E/O), draw-out (D/O). Used tested with report.
SKU: MCCB2044
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Square D MasterPact NW20N Circuit Breaker 2000 Amp 600 Volt AC E/O D/O

Square D MasterPact NW20N Circuit Breaker; cat# WL1FFR33A9SXXXXXXX, 2000 Amp, 600 volt AC, 3 pole. With micrologic 5.0A trip unit, LSI functions, electrically operated (E/O), draw-out (D/O). Used tested with report.
SKU: MCCB2045
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Square D Masterpact NW40H2 Circuit Breaker 4000 Amp 600 VAC E/O D/O

Square D NW40H2 MasterPact circuit breaker: cat.# YA5KKR63A3SFBFXXXX, 4000 amp frame, 600 volt AC, three pole, 4000 amp rated. 85kA @ 480V, Micrologic 5.0 P trip unit with LSI functions, Modbus, spring charging motor- 100-130 Volt AC/DC, shunt trip- 24-30 Volt AC/DC, closing coil - 100-130 VAC/DC, electrically operated (E/O), draw-out (D/O), used tested with report.** Small Chip in Bottom RT. Corner**.
SKU: MCCB1506

Square D MasterPact NW50H3 Circuit Breaker 5000 Amp 600 VAC E/O D/O

Square D NW50H3 MasterPact circuit breaker; cat# YA6LLR64A3SFFFXHXA, 5000 amp, 600 volt AC, three pole. With Micrologic 6.0P trip unit, LSIG functions, ground fault, spring charging motor: 100-130 volt AC, shunt trip: 100-130 volt AC/DC, closing coil: 100-130 volt AC/DC, under-voltage has been removed, key interlock, electrically operated (M/O), draw-out (D/O), used tested with report.
SKU: MCCB1927
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Square D MasterPact NW50H3 Circuit Breaker 5000 Amp 600 VAC E/O D/O

Square D NW50H3 MasterPact circuit breaker: cat# YA6LLR64A3SFFFXHXA: 5000 amp, 600 volt AC, three pole. With Micrologic 6.0P trip unit with LSIG functions, spring charging motor: 100-130 volt AC, shunt trip: 100-130 volt AC/DC, closing coil: 100-130 volt AC/DC, under-voltage has been removed, key interlock, electrically operated (E/O), draw-out (D/O). Used tested with report.
SKU: MCCB1928
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Square D NW25H MasterPact Breaker 2500A 600 VAC F/M E/O

Square D NW25H MasterPact Breaker; cat# WL3GGB44A9CFFFXSXX, 2500 amp, 600 volt AC, 3 pole. With micrologic 6.0A trip unit, LSIG functions, ground fault, fixed-mount (F/O), electrically operated (E/O), used tested with report.
SKU: MCCB1998
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Square D NW25H MasterPact Breaker 2500A 600 VAC F/M M/O

Square D NW25H MasterPact Breaker; cat# WL3GGB33A9CFFFXSXX, 2500 amp, 600 volt AC, 3 pole. With micrologic 5.0 trip unit, LSI functions, spring charging motor: 100-130 volts AC, shunt trip: 100-130 volts AC/DC, closing coils: 100-130 volts AC/DC, fixed mount (F/M), electrically operated (M/O), used tested with report.
SKU: MCCB1997
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Square D PAF362000DC2100 Circuit Breaker 2000 Amp 500 Volt DC E/O F/M

Square D PAF362000DC2100 Circuit Breaker; 2000 amp, 500 volt DC, 3 pole, electrically operated (E/O), fixed-mount (F/M). With coil release switch, shunt trip, auxiliary switch. Used tested with report.
SKU: MCCB2210
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Square D SED364000LSGES1C8 Circuit Breaker 4000 Amp 600 Volt AC E/O D/O

Square D SED364000LSGES1C8 Circuit Breaker; 4000 amp, 600 volt AC, 3 pole, electrically operated (E/O), draw-out (D/O). With LSIG functions, ground fault, 100% rating plug cat# RP100, shunt trip, spring charging motor, spring charge contact, shunt close, alarm switches, 8 auxiliary switches, integral ground fault. Used tested with report.
SKU: MCCB2161
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SSD16B216 GE Power Break II 1600 Amp 600 VAC EO/DO LSIG

General Electric SSD16B216 Power Break II; 1600 amp, 600 volt AC, 3 pole. With Micro Versa Trip plus trip unit cat# B216LSIG, 1600 amp rating plug cat# TR16B1600, shunt trip cat # SPST024- 24 VAC, bell alarm cat# SPBAA240- 240 VAC, electric operator cat# SPE120- 120 VAC, remote close cat# SPRCS024- 24 VDC, electrically operated (E/O), draw-out (D/O), used tested with report.
SKU: MCCB1843
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New, Used, and Tested Molded & Insulated Case Circuit Breakers

EMSCO has been specializing in used and refurbished molded & insulated case circuit breakers for over 72 years.


Why Choose EMSCO for Molded Case or Insulated Case Circuit Breakers?

Want to match and replace your existing breakers? End the hassle of retrofitting your electrical system. Our extensive inventory includes a variety of Molded Case Circuit Breakers (MCCBs) and Insulated Case Circuit Breakers that are designed to seamlessly match and replace your existing breakers by brand, amp rating, voltage, frame size, or model.

New and Refurbished Products in Stock

We understand that budgets and preferences differ, so we give you the option of selecting between new and refurbished MCCBs or Insulated Case Breakers, both of which are readily available in our inventory. Choose brand-new circuit breakers for maximum performance and longevity, or look into our refurbished options, which have been rigorously tested and reconditioned to meet industry standards.

Popular Brands and Common Configurations

Our shelves are stocked with breakers from the most trusted and popular brands in the industry, ensuring you have access to dependable products. You'll find common configurations, such as different frame sizes and voltage ratings, making it simple to find the right circuit protection for your application.

Avoiding Costly Operational Downtime

Downtime can be an expensive situation. Our circuit protection products are designed for high performance and durability. You can avoid costly operational downtime due to electrical failures by using our fully-tested Molded Case or Insulated Case breakers. Our products provide reliable power and superior equipment protection.

Electrical Testing Equipment Certifying Quality and Performance

When it comes to the dependability and safety of your electrical systems, we leave nothing to chance. Our breakers are rigorously tested using current testing equipment to ensure that they meet or exceed industry standards. This ensures that your electrical installations are safe and efficient.

  • Overcurrent Protection: We verify that your breakers provide accurate overcurrent protection, guaranteeing the safety of your electrical systems.
  • Trip Time: We measure the time it takes for breakers to respond to overcurrent conditions, ensuring it operates within the specified trip time.
  • Short-Circuit Withstand Capacity: Our testing evaluates the breaker’s ability to withstand short-circuit currents, preventing damage and maintaining safety.
  • Interrupting Capacity: We determine the MCCB's capability to interrupt fault currents, ensuring the utmost protection for your electrical system.

Molded Case Circuit Breaker Specifications

A sample table of ampere ratings, corresponding voltage ratings, and frame sizes for molded case circuit breakers is shown below. Please keep in mind that frame sizes and ratings can differ between manufacturers and models. For precise details on a specific MCCB, always refer to the manufacturer's specifications.

Frame Size

Ampere Rating

Voltage Rating

A

15A

120V, 240V

A

20A

120V, 240V

B

30A

120V, 240V, 480V

B50A120V, 240V, 480V
C60A240V, 480V
C100A240V, 480V
D150A240V, 480V, 600V
D200A240V, 480V, 600V
E250A240V, 480V, 600V
E300A240V, 480V, 600V
F400A240V, 480V, 600V
F600A240V, 480V, 600V
G800A240V, 480V, 600V
G1200A240V, 480V, 600V
H1600A240V, 480V, 600V

This table is a sample representation of frame sizes, ampere ratings, and voltage ratings for Molded Case Circuit Breakers, not an exhaustive list.

Molded case circuit breakers (MCCBs) and insulated case circuit breakers (ICCBs) are two distinct types of circuit protection devices used in electrical systems. Both serve the purpose of interrupting electrical currents in case of faults or overloads, but they differ in construction, application, and performance characteristics. Need Help Now? Call 800-328-1842.