What is earth leakage protection?

Earth leakage protection is a technology which works by monitoring the current flowing through the conductors. 

If the current becomes unbalanced between active and neutral, it indicates some current is flowing elsewhere and that a short circuit and current leakage is present. The device shuts off the power very quickly to prevent the danger of an electric shock.

What is an RCD or RCCB?

An RCD or RCCB is a Residual Current Device or Residual Current Circuit Breaker – an earth leakage protection device. 

This is the device which monitors the flow of current and detects any residual (i.e. an imbalance). 

How does an RCD or RCCB work?

RCD or RCCB compares the values of live and neutral wires. 

In case there is a fault, the current that flows from the neutral wire will reduce. The difference is the residual current, and when it spots the residual current, it triggers the RCCB and, hence, trips off the circuit.