RCD / ELCB (residual current device)

An RCD (residual current device), still commonly called an ELCB in the UAE, constantly compares the current flowing out on the live wire with the current returning on the neutral. If even a small amount leaks away — through a person touching a faulty appliance, or water reaching a socket — it trips in milliseconds and cuts the power. It's the device that guards against electric shock, which is why bathrooms, kitchens and outdoor sockets should sit on one. If yours trips, don't just keep resetting it — it's usually catching a genuine earth fault. Press its built-in test button every few months; if it doesn't trip, get it checked in an electrical safety inspection.