What aspect does a Residual Current Device primarily safeguard against?

A Residual Current Device (RCD) is primarily designed to safeguard against earth leakage currents. This is a critical safety feature in electrical installations, as it detects any imbalance between the live (or phase) and neutral wires. Such an imbalance often indicates that current is escaping to the ground, which poses a significant risk of electric shock or fire due to faulty appliances or wiring.

When an RCD identifies these earth leakage currents, it quickly disconnects the power supply, helping to protect both individuals and property from potential harm. This rapid response is vital in preventing accidents that can occur from prolonged exposure to electrical faults.

While other options like overcurrent protection, voltage surges, and overheating equipment are important aspects of electrical safety, they are managed by different devices or protective mechanisms, such as circuit breakers or surge protectors, rather than RCDs.