When there is an earth leakage current, both RCCB and ELCB are put in place to isolate the circuit. Their operating principles, however, differ. When the incoming and outgoing currents are out of balance, the RCCB operates. However, the ELCB detects and activates when electricity flows across the ground line. There is no need to connect the RCCB to the main earthing system, however, the ELCB requires an earthing connection.