This circuit breaker is an indoor unit with three-phase AC 50Hz and rated voltage 12kV. The rated current is 630-4000A and the breaking current is 25-40kA. It is suitable for switching load of different kinds and can be used as the protection and control unit of power equipment in industrial and mining enterprises, electrical facilities in power plants and substations. Due to special performance of vacuum circuit breakers, it is especially suitable for frequent operation and all operating conditions.