Re: Inquiry about (ELCB)
Kak111 has described an RCD, that is a Residual Current Detector. Its a modern thing. If you want it to trip on overloads you need an RCBO. An ELCB was an old fashioned set up with a breaker with a trip coil which needed 50V to trip it. This trip coil was wired between the earth return of an electrical installation and the true earth. When the earth leakage current of an installation (which flowed through the coil) got too high, the breaker tripped. Problem is that any faulty installation earths that shorted or are connected to a true earth also shunts the trip current away from the trip coil coil so stops the ELCB working.
Frank