A current-activated circuit-breaker used as a safety device for mains-operated electrical tools and appliances.
 Example sentencesExamples
-  The regulations require that a residual current device installed at a workplace shall be kept in a safe working condition and tested on a regular basis by a competent person to ensure its continued effective operation.
 -  He said the warning to immediately install the safety switch or residual current device came after the electrocution of a young mother and her child this month.
 -  Fit a residual current device, RCDs can reduce the risk of electrocution by cutting the power supply if an electrical tool malfunctions or a cable is cut.
 -  The purpose of the residual current device is to monitor the residual current and to switch off the circuit quickly if it rises to a preset level.
 
 Synonyms
circuit breaker, trip switch