Question

(a) What does MCB stand for? Explain the working of MCBs. Why are they preferred over fuses?

(b) Name the principle on which electric fuse works?
[3 MARKS]

Answer 1

Part (a) : 2 Marks
Part (b) : 1 Mark

(a) MCB stands for Miniature circuit breakers.

MCBs are basically a substitute for fuses. These are switches which automatically turn off when the current in a circuit exceeds the safe limit. We turn them on and the circuit is once again complete.
They are preferred over fuses because they are much more user-friendly, because if there is excess current in the circuit they automatically turn off, and the circuit is complete again if we turn it on. While in a fuse, the fuse has to be replaced once excess current passes through it.

(b) Electric fuse works on the principle of the heating effect of current.