The utility model relates to a residual current circuit breaker, include information acquisition module, processor module, protective film piece and at least one commutation device, processor module samples and connects information acquisition module, the control connection protective film piece, and every commutation device comprises the phase module that trades of three setting at the user side, and every trades phase module and all includes processor module 0 and the mutual -inductor that is used for gathering the corresponding phase information that goes up mutually, and processor module 0 is corresponding to concatenate on a looks power supply line of user side, and the commutation device is connected with the processor module communication. Not only can realize the conventional function of circuit breaker through this circuit breaker, realize the trouble operated protective of circuit promptly through the detection line electric current, moreover, can also realize the control of the commutation of user side, solve three -phase laod unbalance's problem. Dedicated commutation device can be saved to this circuit breaker, by residual current circuit breaker realization commutation, has practiced thrift input cost and subsequent maintenance cost.