The setting is formed with two sets power-operated operation mechanism circuit breaker and mechanical interlocking, fuse, wiring terminal etc. the two sets circuit breaker have electric interlocking and mechanical interlocking double protection to prevent the two sets circuit breaker close on at the same time. The setting suits for working voltage 400V (circuit breaker rated working voltage),control the power pass the case,frame board control pushbutton (user self-prepared and connect to) direct control two sets power operated operation mechanism to carry out the power reliable switch over.