What is an MCB and how does it work ?Miniature Circuit Breaker
What is an MCB?
MCB stands for miniature circuit breaker. It is a circuit protection device, capable of protecting a circuit or a piece of equipment from greater damages caused due to short circuits as well as overloads. It is a modular device and can be used as an alternative to fuses. It is capable of sensing overload and short circuit conditions and isolates the power before the whole circuit is damaged.
Working principle
It consists of a bimetallic strip and a plunger arrangement inside. Also, there is a latch arrangement made to hold the contacts closed, when it is turned ON. The bimetallic strip is designed to carry a specific amount of current through it. When the current flowing through it exceeds the limit, the bimetallic strip gets heated up and it bends. As it bends, it knocks down the latch holding the contacts. Higher the current faster shall be the operation.
Similarly, during short circuits, the current flowing through the miniature circuit breaker shall be several times the maximum limit. This activates the plunger arrangement instantaneously, which in turn knocks down the latch and opens the contacts. This is how a miniature circuit breaker works.
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