What is an MCB and what is its working principle?

An MCB (Miniature Circuit Breaker) is an automatic electrical safety device used to protect circuits from overload and short circuit conditions.

It works on two main principles:

• Thermal effect (overload protection): When excess current flows for a longer duration, a bimetallic strip heats up and bends, triggering the MCB to trip and break the circuit.
• Magnetic effect (short circuit protection): In case of a sudden surge in current, a strong magnetic field is generated, which instantly trips the switch and disconnects the circuit.

Unlike a fuse, an MCB does not need to be replaced after operation. It can be reset manually, making it more convenient and reliable.

MCBs are widely used in homes and industries for safe and efficient circuit protection.