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.
  • Sprecher and Schuh L8-15/1/C miniature circuit breaker Sprecher and Schuh L8-15/1/C side view

    L8-15/1/C

    Sprecher + Schuh L8-15/1/C single pole 15 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
    Add to Cart
  • 1492-SPM1C030 miniature circuit breaker 1492-SPM1C030 side view

    1492-SPM1C030

    Allen Bradley AB 1492-SPM1C030 single pole miniature supplementary circuit breaker rated for 3 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
    Add to Cart
  • 1492-SPM1C200 miniature circuit breaker 1492-SPM1C200 side view

    1492-SPM1C200

    Allen Bradley AB 1492-SPM1C200 single pole miniature supplementary circuit breaker rated for 20 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
    Add to Cart
  • 1492-SPM1C250 miniature circuit breaker 1492-SPM1C250 side view

    1492-SPM1C250

    Allen Bradley AB 1492-SPM1C250 single pole miniature supplementary circuit breaker rated for 25 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
    Add to Cart
  • 1492-SPM1C020 miniature circuit breaker 1492-SPM1C020 side view

    1492-SPM1C020

    Allen Bradley 1492-SPM1C020 single pole miniature supplementary circuit breaker rated for 2 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 small...

    MSRP: $52.17
    $33.48
    Add to Cart
  • Sprecher and Schuh L8-32/1/C miniature circuit breaker Sprecher and Schuh L8-32/1/C side view

    L8-32/1/C

    Sprecher + Schuh L8-32/1/C single pole 32 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
    Add to Cart
  • Moeller NZMB1-A100-NA circuit breaker

    NZMB1-A100-NA

    Eaton/Moeller NZMB1-A100-NA 3-pole circuit breaker with basic switching capacity and a thermo-magnetic release. This 100 AMP molded case circuit breaker has a 600A-1000A short-circuit release and an adjustable overload release from 80A-100A. Line and...

    MSRP: $521.00
    $504.32
    Add to Cart
  • Eaton/Moeller NZMB1-A25-NA circuit breaker

    NZMB1-A25-NA

    Eaton/Moeller NZMB1-A25-NA 3-pole circuit breaker with basic switching capacity and a thermo-magnetic release. This 25 AMP molded case circuit breaker has a 350A short-circuit release and an adjustable overload release from 20A-25A. Line and load side...

    MSRP: $433.00
    $395.85
    Add to Cart
  • TD125NU-FMU-LL-80

    TD125NU-FMU-LL-80

    LS / Susol TD125NU 35kA, 80 AMP, 3 pole molded case circuit breaker (MCCB) with adjustable thermal and fixed magnetic trip unit and line and load side lugs. Click here to view a PDF file on this LG Circuit Breaker On TD125U to TS800U circuit breakers,...

    MSRP: $468.95
    $0.00
  • 1492-SPM1C040 miniature circuit breaker 1492-SPM1C040 side view

    1492-SPM1C040

    Allen Bradley AB 1492-SPM1C040 single pole miniature supplementary circuit breaker rated for 4 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
    Add to Cart