A volt is the potential electrical energy if the current is allowed to flow to a specific source. The UK electricity main supply is approx. 240 volts, and if not used properly has the potential to seriously harm. Electrical appliances, circuits, cables and plugs are designed to reduce the chance of an electric shock.
RCD – A Residual Current Device, or RCD, is a safety device that automatically switches off electricity, in some circuits, if a fault is detected. They are designed to prevent electric shocks and electrical fires. This device offers a level of personal protection the ordinary circuit breakers do not provide.