GlossaryElectricalRCCB / RCD
RCCB / RCD
Distribution Protection · Also: RCD, ELCB, Earth leakage breaker, Residual current device
In short
Trips on earth leakage — the life-saving device that cuts power if current leaks to earth.
Notes
An RCCB (also called RCD; older talk may say ELCB) watches for imbalance between live and neutral. If current leaks — for example through a person or damp fault — it trips fast.
Wet areas, outdoor points, and water heaters should sit behind proper earth-leakage protection. Test buttons on the device are there to be used occasionally.