rcd fault

An **RCD fault** refers to a situation where a **Residual Current Device (RCD)** detects an imbalance between the live (phase) and neutral conductors and trips (switches off the circuit).

An RCD monitors the current flowing in the live and neutral wires. Under normal conditions, the current flowing out through the live wire should equal the current returning through the neutral wire. If there is a difference (called residual current), it usually means some current is leaking to earth — possibly through faulty wiring, damaged insulation, or even through a person — which can cause electric shock.

When this imbalance exceeds a set threshold (commonly 30 mA for personal protection), the RCD disconnects the power to prevent injury or fire.

So, an **RCD fault** typically indicates:
- Earth leakage
- Faulty appliance
- Damaged cable insulation
- Moisture ingress
- Wiring error
- A genuine electrical shock hazard

It is a safety trip designed to protect people and property.