Novel residual-current circuit breaker

The novel residual-current circuit breaker comprises an N-stage shell, an L-stage shell and a middle shell, an N-stage circuit breaker is formed between the N-stage shell and the middle shell, an L-stage circuit breaker is formed between the L-stage shell and the middle shell, the N-stage circuit breaker and the L-stage circuit breaker are respectively provided with an N-stage wiring hole and an L-stage wiring hole, and the N-stage circuit breaker and the L-stage circuit breaker are respectively provided with an N-stage wiring hole and an L-stage wiring hole. The N-stage shell is provided with an N-stage wiring hole and an L-stage wiring hole, the N-stage wiring hole and the L-stage wiring hole are located on the same side, the other side of the N-stage shell is provided with an L-stage wire inlet hole, an external lead hole is formed below the N-stage wiring hole, an external lead is arranged in the external lead hole, and the external lead enters the N-stage shell from the external lead hole and then is seq