Residual Current Circuit Breaker ensures protection from shocks and leakage current. The Breaker has the feature that the secondary winding is connected to a sensitive electromagnetic trip relax, which operates the trip mechanism. The Breaker has the feature that imbalance is detected by the core balanced current transformer and is tripped and supply to load is interrupted. The Residual Current Circuit Breaker has the feature that trip mechanism is operated at a residual current between 50 to 100% of its rated tripping current.