ZW20-12 and ZW32-12 series outdoor high voltage AC vacuum circuit breakers are mainly used for breaking and closing load current, overload current and short-circuit current in 12kV three-phase AC 50Hz transmission and distribution system, and can realize the protection of distribution network automation step by step. It is suitable for protection and control in substation and distribution system of industrial and mining enterprises. It is more suitable for rural power grid and places with frequent operation, especially for the needs of urban power grid and rural power grid construction and transformation.