ELCB (Earth Leakage Circuit Breaker) is same device as RCCB (Residual Current Circuit Breaker) or an RCD (residual current device). These devices add an extra layer of protection in residential electrical circuits on top of MCBs. An ELCB or RCCB trips and disconnects a circuit on detecting unbalanced current between ‘line’ and ‘neutral’. A typical example is sometimes when we get a very light shock on touching bathroom taps, even though taps have no electrical termination. Its due to earth leakage current that flows through walls/floor (caused due to minor negligence in wiring practices). RCCB detects this faulty wiring, which can be disastrous in some circumstances and trips, thereby forcing the consumer to get the wiring corrected.