residual current device
- Its abbreviation is RCD. A special type of circuit breaker which continuously monitors the current flowing in both the hot and neutral wires. Normally, this amount would be equal, but if even if a slight current leaks to ground, be it through the ground wire or through a person being shocked, there will be more current in one than the other. The RCD detects this, and shuts off all current flow within about 0.025 seconds, which should be fast enough to prevent any real harm to a person. Some RCDs detect current differences of less than 0.001 amperes. There are various types of RCDs, including the receptacle type, which replaces a conventional outlet, and those installed in a circuit-breaker panel. Also called ground fault circuit interrupter.
- noun a piece of equipment that checks the electrical supply from a socket and trips a switch if any changes in the flow are detected, protecting people and equipment.