What happens when the earth leakage path is absent in a circuit with an RCD?

When there is an absent earth leakage path in a circuit that includes a residual current device (RCD), it significantly affects the RCD's ability to function correctly. The RCD is designed to monitor the imbalance of electric current flowing in and out of a circuit. It detects if there's a leakage of current, which can occur when there is a fault in the wiring or an electrical appliance.

If the earth leakage path is missing, the RCD will not be able to detect this imbalance. As a result, it cannot trip and disconnect the circuit in the event of a fault. This means that the RCD will not function properly, compromising the safety mechanism it is designed to provide.

Understanding how RCDs operate, it becomes clear why the absence of an earth leakage path would lead to improper functioning. For instance, if an earth fault occurs but there's no pathway for the current to escape to ground, the RCD simply cannot perceive that there's an irregularity. Consequently, this situation creates a hazardous condition, increasing the risk of electric shock or fire.