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Molded & Insulated Case Circuit Breakers

Home > Store > Circuit Breakers > Molded & Insulated Case Circuit Breakers

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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.
Picture of Schneider Electric MasterPact NW30H Circuit Breaker 3000 Amp 600 VAC M/O D/O

Schneider Electric MasterPact NW30H Circuit Breaker 3000 Amp 600 VAC M/O D/O

Schneider Electric NW30H MasterPact circuit breaker; cat # WG3HHR33A9CFFFWXEX, 3000 amp, 600 Volt AC, three pole. With MicroLogic 5.0A with LSI functions, manually operated (M/O), draw-out (D/O). Used tested with report.
SKU: MCCB1917
$6,000.00
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Picture of NW30H Schneider Electric MasterPact Breaker 3000 Amp 600 VAC LSI M/O D/O

NW30H Schneider Electric MasterPact Breaker 3000 Amp 600 VAC LSI M/O D/O

Schneider Electric NW30H MasterPact circuit breaker; cat # WG3HHR33A9CFFFWXEX, 3000 amp, 600 volt AC, three pole. With MicroLogic 5.0A with LSI functions, manually operated (M/O), draw-out (D/O). Used tested with report.
SKU: MCCB1918
$6,000.00
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Picture of NW08H1 Square D MasterPact Breaker 800 Amp 600 VAC LSIG M/O D/O

NW08H1 Square D MasterPact Breaker 800 Amp 600 VAC LSIG M/O D/O

Square D NW08H1 MasterPact circuit breaker; cat# WA4AAR44A9SXXXXXXX, 800 amp, 600 volt, three pole. With MicroLogic 6.0A trip unit with LSIG functions, ground fault, manually operated (M/O), draw-out (D/O). Used tested with report.
SKU: MCCB1919
$4,500.00
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Picture of Square D MasterPact NW08H1 Circuit Breaker 800 Amp 600 VAC M/O D/O

Square D MasterPact NW08H1 Circuit Breaker 800 Amp 600 VAC M/O D/O

Square D NW08H1 MasterPact circuit breaker; cat# WA4AAR44A9SXXXXXXX, 800 amp, 600 volt AC, three pole. With MicroLogic 6.0A trip unit with LSIG functions, ground fault, manually operated (M/O), draw-out (D/O). Used tested with report.
SKU: MCCB1920
$4,500.00
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Picture of Square D MasterPact NW08H1 Circuit Breaker 800 Amp 600 VAC M/O D/O

Square D MasterPact NW08H1 Circuit Breaker 800 Amp 600 VAC M/O D/O

Square D NW08H1 MasterPact circuit breaker; cat# WA4AAR44A9SXXXXXXX, 800 amp, 600 volt AC, three pole. With Micrologic 6.0A trip unit, LSIG functions, ground fault, manually operated (M/O), draw-out (D/O), used tested with report.
SKU: MCCB1922
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Picture of NW08H1 Square D MasterPact Breaker 800 Amp 600 VAC LSIG M/O D/O

NW08H1 Square D MasterPact Breaker 800 Amp 600 VAC LSIG M/O D/O

Square D NW08H1 MasterPact breaker; cat# WA4AAR44A9SXXXXXXX, 800 amp, 600 volt AC, three pole. With MicroLogic 6.0A trip unit, LSIG functions, ground fault, manually operated (M/O), draw-out (D/O), used tested with report.
SKU: MCCB1923
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Picture of Square D MasterPact NW50H3 Circuit Breaker 5000 Amp 600 VAC M/O D/O

Square D MasterPact NW50H3 Circuit Breaker 5000 Amp 600 VAC M/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, under-voltage has been removed, key interlock, manually operated (M/O), draw-out (D/O), used tested with report.
SKU: MCCB1927
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Picture of Square D MasterPact NW50H3 Circuit Breaker 5000 Amp 600 VAC M/O D/O

Square D MasterPact NW50H3 Circuit Breaker 5000 Amp 600 VAC M/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, under-voltage has been removed, key interlock, manually operated (M/O), draw-out (D/O). Used tested with report.
SKU: MCCB1928
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Picture of Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 VAC M/O D/O

Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 VAC M/O D/O

Square D NW40H2 MasterPact circuit breaker; cat # YA5KJR44A9SXXXXXXA, 4000 amp, 600 volt AC, three pole. With Micrologic 6.0 amp trip unit, LSIG functions, ground fault, 3200 amp rating plug, key interlock, manually operated (M/O), draw-out (D/O), used tested with report.
SKU: MCCB1930
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Picture of Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 VAC M/O D/O

Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 VAC M/O D/O

Square D NW40H2 MasterPact circuit breaker; cat# YA5KJR44A9SXFXXXXA, 4000 amp, 600 volt AC, three pole. With Micrologic 6.0 amp trip unit, LSIG functions, ground fault, 3200 amp rating plug, key interlock, manually operated (M/O), draw-out (D/O), used tested with report.
SKU: MCCB1931
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Picture of TCL88SS GE Power Break Breaker 800 Amp 600 VAC M/O D/O

TCL88SS GE Power Break Breaker 800 Amp 600 VAC M/O D/O

General Electric TCL88SS Power Break Circuit Breaker; 800 amp, 600 volt AC, 3 pole. With 600 amp rating plug cat.# TR8S600, Micro Versa Trip RMS-9 cat.#TS20LSIT1, LSI functions, auxiliary switch, shunt trip- 120 to 240 volt AC, draw-out (D/O) carriage substructure cat.# TDOSO8L, manually operated (M/O). Used tested with report.
SKU: MCCB1099
$2,400.00
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Picture of Square D NW25H MasterPact Breaker 2500A 600 VAC F/M M/O

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, fixed mount (F/M), electrically operated (M/O), used tested with report.
SKU: MCCB1997
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Picture of Square D NW25H MasterPact Breaker 2500A 600 VAC F/M M/O

Square D NW25H MasterPact Breaker 2500A 600 VAC F/M M/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), manually operated (M/O), used tested with report.
SKU: MCCB1998
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Picture of Square D MasterPact NW20N Circuit Breaker 2000 Amp 600 Volt AC E/O D/O

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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Picture of Square D MasterPact NW20N Circuit Breaker 2000 Amp 600 Volt AC E/O D/O

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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Picture of Square D NW12HF MasterPact Automatic Switch 1200 Amp 600 Volt 4 Pole M/O F/M

Square D NW12HF MasterPact Automatic Switch 1200 Amp 600 Volt 4 Pole M/O F/M

Square D NW12HF MasterPact Automatic Switch; cat# BL3CCVSSX9CFBFXXCA, 1200 amp, 600 volt AC, 4 pole, manually operated (M/O), fixed-mount (F/M). Used tested with report.
SKU: MCCB2052
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Picture of GE Power Break TC2020TTR Circuit Breaker 2000 Amp 600 Volt AC

GE Power Break TC2020TTR Circuit Breaker 2000 Amp 600 Volt AC

General Electric Power Break TC2020TTR Circuit Breaker; 2000 amp, 600 volt AC, 3 pole. With MicroVersaTrip plus trip unit cat# C220LSIG, LSIG functions, ground fault, 2000 amp rating plug cat# TR20B2000. Used tested with report.
SKU: MCCB2053
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Picture of Square D MasterPact NW30H Circuit Breaker 3000 Amp 600 Volt AC M/O F/M

Square D MasterPact NW30H Circuit Breaker 3000 Amp 600 Volt AC M/O F/M

Square D MasterPact NW30H Circuit Breaker; cat# WL3HGG43A9SXFXXXXX 3000 amp, 600 volt AC, 3 pole. With 2500 amp rating plug, manually operated (M/O), fixed-mount (F/M). Used tested with report. **No Trip Unit
SKU: MCCB2064
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Picture of Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 Volt AC D/O

Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 Volt AC D/O

Square D MasterPact NW40H2 Circuit Breaker; cat# YA5KKR64A3GGFFWXCX, 4000 amp, 600 volt AC, draw-out (D/O). With Micrologic 6.0 P trip unit, LSIG functions, ground fault, 4000 amp rating plug. Used tested with report.
SKU: MCCB2082
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Picture of Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 Volt AC

Square D MasterPact NW40H2 Circuit Breaker 4000 Amp 600 Volt AC

Square D MasterPact NW40H2 low- voltage power circuit breaker; 4000 amp cat# YA5KKR64A3GGFFWXCX, 600 volt AC, 3 pole. With micrologic 6.0 P trip unit, LSIG functions, ground fault. Used tested with report.
SKU: MCCB2083
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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.