Residual Current Circuit Breakers

The RCB works on the principle of current balance. The Incoming conductors (Phase & neutral) are passed through the very sensitive torroid transformers from the primary winding and secondary electromagnetic relay, which operates the trip mechanism. Normally the contracts are held closed by a spring and open when this is released. If leakage occurs from either of phases or neutral side of circuit in this condition currents are unbalanced by an amount of leakage current and if this reached the rated tripping current of RCCB/ELCB then it trips and save precious human life.