MCB (Miniature Circuit Breaker) is a safety circuit which is equipped with a safety thermal (bimetal) for the safety and well equipped overload relays electromagnetic short circuit for safety. MCB widely used for a safety circuit one phase and three phase. Profit using MCB, namely: Can be decided despite a series of three phase circuit short on one line. Can be reused after a series of repair due to circuit short or overload. Having a good response in case of short circuit or more expense. At MCB, there are two types of safety, namely the thermal and electromagnetic, therma protection function to secure the flow of Overload safety while working for the electromagnetic safeguard in case of short circuit. MCB has a thermal safety on the same principle with the thermal overload that is using two metals that are incorporated (Bimetal), the thermal protection has a delay, this depends on the size of flows that must be secured, while Electromagnetic safety using a coil that can ...