An MCB is crucial to protect any electrical circuit from damage caused by short circuit or overload. Whenever an overload of the electrical wiring is detected a circuit breaker will very quickly cut the power until the problem can be spotted, examined and fixed. Once the issue has been identified they can be easily reset and therefore resume normal operation after tripping. Each little circuit breaker typically has its own circuit to maintain, for example one to control downstairs lighting and another upstairs. Kitchen appliances and electric showers also often have their own circuit.