Circuit Breakers

Miniature Circuit Breakers from 1 to 63 AMP in B, C and D trip curves

When deciding which miniature circuit breaker is best for any application, it is important to determine what type of protection is necessary.  For these MCB's, there are two important factors to consider when choosing which breaker is appropriate:

  1. Supplementary or Branch Circuit Protection
    1. Supplementary protectors are the most common type, but since branch circuit protection is not required, a separate device such as a fuse or molded case circuit breaker must be used upstream
    2. Branch Circuit protectors  are listed as a primary protection device and can be used alone without the need for an additional protection device

Determining the trip curve needed for your miniature circuit breaker

Miniature circuit breakers can come in 7 different trip curve ratings, with B, C and D being the most common.  It is imperative that the correct trip curve is chosen the effectively protect the equipment that is downstream from this device.  Listed below are the three most common trip curves along with a brief description of suitable applications:

  1. B-curve : Suitable for applications where protection against low level short circuit faults in control wiring is desired.  Instantaneous trip is 3 to 5 x continuous rating of device (In). Applications include PLC wiring, business equipment,
    lighting, appliances and some motors. Low magnetic trip point.
  2. C-Curve : Suitable for applications where medium levels of inrush current are expected. Instantaneous trip is 5 to 10 x rating of device (In). Applications include small transformers, lighting, pilot devices, control circuits, and coils. Medium magnetic trip point.
  3. D-curve : Suitable for applications where high levels of inrush current are expected. Instantaneous trip is 10 to 20 x rating of device (In). The high magnetic trip point prevents nuisance tripping in high inductive applications such as motors, transformers, and power supplies.
  • 1492-SP miniature circuit breaker 1492-SP side view

    1492-SP

    Allen Bradley 1492-SP Single Pole Miniature Supplementary Circuit Breaker The Allen Bradley 1492-SP is a high-quality single pole miniature supplementary circuit breaker designed for reliable protection in a wide range of applications. Available with B,...

    MSRP: $52.17
    $33.48
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  • Sprecher and Schuh L8-5/1/C miniature circuit breaker Sprecher and Schuh L8-5/1/C side view

    L8-5/1/C

    Sprecher + Schuh L8-5/1/C single pole 5 AMP miniature supplementary circuit breaker with C trip curve rating. This trip rating is effective where medium levels on inrush are expected, most times in applications that include lighting, transformers, pilot...

    MSRP: $52.17
    $33.48
    Add to Cart
  • 1492-SPM1C050 miniature circuit breaker 1492-SPM1C050 side view

    1492-SPM1C050

    Allen Bradley AB 1492-SPM1C050 single pole miniature supplementary circuit breaker rated for 5 AMPS with a C trip curve rating for medium levels of inrush current. expected. Instantaneous trip is 5 to 10 x rating of device (In). Applications include...

    MSRP: $52.17
    $33.48
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  • Eaton/Moeller NZM2 cover

    NZM2 Cover

    Eaton / Moeller NZM2 replacement cover for all NZMB2, NZMN2, NZMH2 and NS2 Moeller molded case circuit breakers.  This replacement cover is used when attaching any rotary handle assembly of either direct mount or through the door operators...

    MSRP: $110.00
    $64.67
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  • 1492-SPM1C100 miniature circuit breaker 1492-SPM1C100 side view

    1492-SPM1C100

    Allen Bradley AB 1492-SPM1C100 single pole miniature supplementary circuit breaker rated for 10 AMPS with a C trip curve rating for medium levels of inrush current. expected. Instantaneous trip is 5 to 10 x rating of device (In). Applications...

    MSRP: $52.17
    $33.48
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  • Sprecher and Schuh L8-1/1/C miniature circuit breaker Sprecher and Schuh L8-1/1/C side view

    L8-1/1/C

    Sprecher + Schuh L8-1/1/C single pole 1 AMP miniature supplementary circuit breaker with C trip curve rating. This trip rating is effective where medium levels on inrush are expected, most times in applications that include lighting, transformers, pilot...

    MSRP: $52.17
    $33.48
    Add to Cart
  • 1492-SPM1C150 miniature circuit breaker 1492-SPM1C150 side view

    1492-SPM1C150

    Allen Bradley AB 1492-SPM1C150 single pole miniature supplementary circuit breaker rated for 15 AMPS with a C trip curve rating for medium levels of inrush current. expected. Instantaneous trip is 5 to 10 x rating of device (In). Applications...

    MSRP: $52.17
    $33.48
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  • 1492-SPM1C010 miniature circuit breaker 1492-SPM1C010 side view

    1492-SPM1C010

    Allen Bradley AB 1492-SPM1C010 single pole miniature supplementary circuit breaker rated for 1 AMP with a C trip curve rating for medium levels of inrush current. expected. Instantaneous trip is 5 to 10 x rating of device (In). Applications include...

    MSRP: $52.17
    $33.48
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  • Sprecher and Schuh L8-10/1/C miniature circuit breaker Sprecher and Schuh L8-10/1/C side view

    L8-10/1/C

    Sprecher + Schuh L8-10/1/C single pole 10 AMP miniature supplementary circuit breaker with C trip curve rating. This trip rating is effective where medium levels on inrush are expected, most times in applications that include lighting, transformers,...

    MSRP: $52.17
    $33.48
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  • 1492-SPM1C300 miniature circuit breaker 1492-SPM1C300 side view

    1492-SPM1C300

    Allen Bradley AB 1492-SPM1C300 single pole miniature supplementary circuit breaker rated for 30 AMPS with a C trip curve rating for medium levels of inrush current. expected. Instantaneous trip is 5 to 10 x rating of device (In). Applications...

    MSRP: $52.17
    $33.48
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  • Sprecher and Schuh L8-20/1/C miniature circuit breaker Sprecher and Schuh L8-20/1/C side view

    L8-20/1/C

    Sprecher + Schuh L8-20/1/C single pole 16 AMP miniature supplementary circuit breaker with C trip curve rating. This trip rating is effective where medium levels on inrush are expected, most times in applications that include lighting, transformers,...

    MSRP: $52.17
    $33.48
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  • Sprecher and Schuh L8-30/1/C miniature circuit breaker Sprecher and Schuh L8-30/1/C side view

    L8-30/1/C

    Sprecher + Schuh L8-30/1/C single pole 30 AMP miniature supplementary circuit breaker with C trip curve rating. This trip rating is effective where medium levels on inrush are expected, most times in applications that include lighting, transformers,...

    MSRP: $58.58
    $37.77
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