What type of protective measure does an RCD offer in electrical systems?

An RCD, or Residual Current Device, primarily offers protection against electric shock. It functions by monitoring the electrical current flowing through the live and neutral wires of a circuit. If it detects an imbalance, which can occur if current is leaking through a person who touches a live conductor, the RCD quickly cuts off the power supply. This rapid disconnection is crucial in preventing severe injury or fatality caused by electric shock.

The other protective measures mentioned, such as surge protection, overvoltage protection, and short circuit prevention, refer to different types of electrical protection mechanisms. Surge protectors guard against voltage spikes, overvoltage protection devices help prevent damage from excess voltage levels, and circuit breakers or fuses are designed to interrupt the flow of current in the event of a short circuit. These devices address various electrical faults but do not directly prevent the risk of electric shock like an RCD does.