MCB protects a circuit from both short circuit and overload.

In the event of a short circuit, the MCB trips almost instantly to protect the circuit from the high fault current that can cause extensive damage. The tripping mechanism of an MCB operates on the principle of magnetic force generated by the high current, which moves the trip bar and opens the contacts. This ensures a quick and reliable response to short circuit faults.

In the case of an overload, the MCB protects the circuit by sensing the amount of current passing through the circuit. When the current exceeds the rated value of the MCB for a certain period of time, it trips to protect the circuit from damage due to overheating. The tripping mechanism for overload protection operates on the principle of thermal heating, with a bimetallic strip that deforms and moves the trip bar to open the contacts.