What Is MCB?
MCB (miniature circuit breaker) is an electromagnetic device that embodies the entire enclosure in a molded insulating material. Main function of MCB is to open the circuit automatically when current passes through it exceeding the value for which MCB is set. MCB can be manually switched ‘On’ and ‘Off’ just like normal switches if necessary.
The device starts its operation for protection whenever overload occurs long enough to create danger to circuit. MCB does not respond to the transient loads like motor starting currents and switching surges. Usually, they are designed to work at less than 2.5 milliseconds during the short circuit fault and 2 seconds to 2 minutes when overload occurs.
Miniature circuit breakers are manufactured in varied pole versions like single, double, triple and four pole structures with distinct fault levels of current.