What is the key purpose of a Residual Current Device (RCD)?

The key purpose of a Residual Current Device (RCD) is to prevent electric shock. RCDs are designed to detect imbalances between the live and neutral currents in an electrical circuit. When an imbalance occurs, which can happen if a person comes into contact with a live conductor and leakage current flows through their body to the ground, the RCD quickly disconnects the electrical supply to prevent potential harm.

By continuously monitoring the current flowing through the circuit, an RCD can respond rapidly, often in milliseconds, to effectively reduce the risk of serious injury or fatalities caused by electric shock. This safety device is particularly important in environments where moisture is present, such as bathrooms or outdoor settings, where the risk of shock is heightened.

While other devices serve to protect against specific risks, such as overcurrent or voltage regulation, the distinctive function of an RCD is its focus on detecting and disconnecting current that could result in electric shock, making it an essential safety measure in electrical installations.