What is the purpose of an RCD?

An RCD, or Residual Current Device, serves a critical safety function by detecting earth faults and disconnecting the circuit when it senses an unbalanced current between the live and neutral conductors. This imbalance often occurs when there is a leakage current, which can happen if a person comes into contact with a live part of the installation or if there is a fault in the wiring. By quickly disconnecting the power supply, the RCD greatly reduces the risk of electric shock and prevents potential fire hazards.

This proactive measure is essential for ensuring the safety of individuals and protecting equipment, making the correct answer focused on its role in detecting and disconnecting circuits due to earth faults. The other options do not align with the primary function of an RCD; enhancing electrical flow, monitoring energy consumption, or increasing voltage stability are not roles attributed to this safety device.