An RCD can save lives. RCDs will prevent electrocution by cutting the power to a circuit in the event of earth leakage.
Following are descriptions and images of devices including RCDs, circuit breakers, combination RCD and circuit breaker, portable RCDs, and powerpoint RCDs.
An RCD is a safety device that prevents electrocution by cutting the electricity supply immediately. It works on the principle that the electricity flowing into a circuit must be equal to the current flowing out of a circuit. When you receive a shock it means an electrical current has passed through the body directly to earth.
RCDs are fitted at the meter box and will have a test button on them. If you press the ‘test’ button or the RCD has detected an issue, the on/off switch will go to the ‘off’ position.
A minimum of two RCDs are required to ensure some light and power remains if one operates. Two RCDs also reduces the possibility of tripping due to some appliances which have low levels of earth leakage.
Circuit breakers and fuses are designed to protect electrical cables and fittings installed in the home from overloading and short circuits. They cut the power when electrical wiring in the home has too much current flowing through it. They are designed to prevent electrical fires, not electrocution.
Home owners can choose to install combined circuit breaker and RCDs. These devices protect the electrical circuits and appliances as well as preventing electrocution and are an option in meter boxes with little or not spare space.
Portable RCDs attached to a power board or extension lead protects you when using power tools or electrical appliances outside.
Power point RCDs
RCDs fitted to a power point can be recognised by the test button on the face of the plate. They are made for protecting electrical appliances in your bathrooms and workshops.