rccb

Residual current circuit breaker

A residual current device (RCD), or residual-current circuit breaker (RCCB), also known as an RCCB or RCD, is an electrical wiring device that to interrupting the circuit by comparing the return and return current of the circuit, and in the event of a difference between the current and the return current. In normal electrical circuits, the current flow is equal to the return current, but if for any reason the current between the phase wire and the null (in single-phase circuits) is different, this key will act as a protector.