Acti9 C120N MCB 4P C 120A 10000A 415V. There are many types of single or multi-pole electrical circuit breakers, which are manufactured to protect electrical conductors from overheating. The machines are used as separators (switches) for self-contained devices or as main separators. Thus, single-phase automatic machines are widely used in our homes for washing machines, electric ovens, refrigerators, air conditioners, etc. While the other group belongs to three-phase automata that extend to industrial use.