Residual Current Devices (RCDs) are one of the most critical safety components in modern electrical installations, designed to save lives by instantly cutting power. An RCD is not the same as a fuse or circuit breaker, which primarily protect against overloads and short circuits.
The Life-Saving Difference
An RCD monitors the flow of electricity in a circuit. If it detects even a small imbalance (meaning electricity is escaping, perhaps through a person touching a live wire), it trips the circuit in milliseconds. This speed is what makes the RCD a life-saver, as it can stop a fatal electric shock. Modern consumer units require RCD or RCBO (Residual Current Breaker with Overcurrent protection) protection on all circuits to meet current UK safety standards (BS 7671). If your Southampton home still uses an old fuse board, an upgrade is strongly recommended for RCD protection.