Circuit breaker with leakage protection function or residual current protection function

The utility model discloses a circuit breaker with a leakage protection function or a residual current protection function, which comprises a base and a zero-sequence mutual inductor, and is characterized in that the base is provided with a mutual inductor installation area, and the zero-sequence mutual inductor is located in the mutual inductor installation area; the device further comprises a limiting support, the limiting support is detachably arranged in the base, and the limiting support is located beside the zero sequence mutual inductor in the width direction of the base. A first limiting groove is formed in the mutual inductor mounting area, one side of the zero-sequence mutual inductor is limited by the first limiting groove, and the other side of the zero-sequence mutual inductor is limited by the limiting bracket, so that the zero-sequence mutual inductor is prevented from shaking in the width direction of the base; the zero-sequence mutual inductor has the advantage of being capable of effectively