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What does Miniature Circuit Breakers (MCB) mean and when looking at the types, B, C, and D, what should I know?

When looking for circuit breakers, I always come across MCB's, B, C and D. What does this exactly mean and what do you have to consider?

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    We have lots of great articles on within this area.

    Example Product: #usr58386


    What is the difference between Type B, C and D miniature circuit breakers? gives some great definitions of MCB and what B, C and D are. 

    What are Miniature Circuit Breakers (MCB) - (Miniature circuit breakers (MCB) are characterized by their low current ratings and fixed trip settings. Normally, MCBs have current ratings below 100 Amperes and, as their name implies, they have a compact size. There are three main types of MCBs, classified according to the current range at which they trip instantly.)

    What does the tripping characteristic of automatic circuit breakers / circuit breakers mean? This is a German article, but gives some great definitions and examples. Just make sure you click translate to English.

    This jist of it:  

    Circuit breakers with the "B" are normally used in residential installations (light and socket circuits).

    For the  "C" and "D", these short-circuit currents are higher, so that loads with high inrush currents do not trigger the circuit breaker every time they are switched on.

    Therefore LSS with the  "C" are used for motor circuits (circular saws and smaller pumps), air conditioners and larger lamp groups.

    And the "D" is used for strong inductive loads such as welding transformers transformers, electromagnets or capacitive loads such as large capacitors.

    release characteristic

    Holding current (AC)

    Tripping current (AC)


    3 x rated current

    5 x rated current


    5 x rated current

    10 x rated current


    10 x rated current

    20 x rated current

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