What type of device uses a RCD to prevent electrical shock?

A Ground Fault Circuit Interrupter (GFCI) is specifically designed to prevent electrical shock by detecting ground faults, which happen when there is an unintended path for current flow, such as through a person who has come into contact with a live electrical source. The GFCI works by continuously monitoring the electrical current flowing through a circuit. If it detects any discrepancy between the outgoing and incoming current, it shuts off the power almost instantaneously—much faster than a standard circuit breaker would.

This rapid response is crucial in preventing severe electrical shocks or electrocution, particularly in wet or damp areas like bathrooms, kitchens, and outdoor locations where such hazards are more prevalent. The effectiveness of a GFCI in protecting people sets it apart from other devices mentioned in the choices.

The Arc Fault Circuit Interrupter (AFCI) focuses on preventing electrical fires caused by arc faults and does not specifically target electrical shock prevention. Surge protectors are designed to protect electrical devices from voltage spikes, and voltage regulators stabilize the output voltage supplied to devices, neither of which directly provide shock protection like a GFCI does.