Why is my RCD tripping?

An RCD monitors electricity flowing through a circuit and disconnects the supply when it detects an imbalance. In everyday terms, it is warning that current may be taking a path it should not. The device may protect several circuits, so a trip does not immediately identify one appliance or one room.

The pattern is useful. If the RCD trips when one appliance starts, that appliance or its connection needs checking. If it trips when a bathroom fan, outdoor light or washing machine is used, moisture or equipment may be involved. If it trips with nothing obvious switched on, the wiring or a fixed connection may need testing.

Keep your hands and the floor dry. Turn off or unplug appliances from their normal plugs only where you can do so safely. Do not touch anything wet, damaged, hot or scorched. Check whether the trip is linked to one room or one item, and write down what was running when it happened.

You can try one reset using the switch as designed. If it will not stay on, leave it off. If it stays on until a particular appliance is used, leave that appliance disconnected and do not test it repeatedly. An extension lead, socket or plug that is warm, cracked, loose or marked should not be used.

Do not remove socket fronts, open the consumer unit or test live parts. A diagnosis needs suitable test equipment and an electrician who can determine whether the fault is in an appliance, an accessory, a circuit or the protective device.

If the trip affects a rented property, tell the landlord or agent what happened and when. If the power has gone off, protect food and avoid using candles near anything that may have a fault. A torch is safer for checking the room. Do not let a lack of convenience push you into opening the board or repeatedly restoring a supply that will not stay on.

A trip when the kettle, washing machine or cooker starts may point to that item or its supply, but the timing is not proof. A trip after rain can make outdoor equipment or damp areas relevant. A trip when heating or a pump starts may involve fixed equipment. An intermittent trip is still worth reporting, even if the power returns.

Tell the electrician what changed before the first trip. Mention new appliances, decorating, drilling, leaks, bathroom work and outdoor work. Also say whether the RCD resets immediately, after everything is unplugged, or only after a period with the circuit off. Those details help the fault-finding process.

Leave the affected supply off when there is a burning smell, smoke, scorch mark, buzzing, exposed conductors or water near sockets, switches or the consumer unit. Do not put yourself between water and the electrical installation. If you can isolate power without touching anything wet and without entering danger, follow the property's normal safety procedure; otherwise leave it alone and call for help.

A protective device that trips is doing its job. Do not ask someone to hold it on, fit a larger fuse or disconnect the RCD. Those actions remove protection while the underlying fault remains. A qualified electrician should test, identify the cause, make the repair and confirm the circuit is safe.

The electrician will ask about the pattern, inspect the accessible installation and use tests to narrow down the fault. They may separate circuits or appliances and check protective devices, connections and insulation. The sequence depends on the property and what is safe to access.

Once the cause is known, you should receive a clear explanation of the repair. It may be an appliance that needs attention, a damaged accessory, moisture that must be resolved or a wiring fault. Do not accept a reset as a permanent fix when the RCD keeps tripping. Hem's electrical team is NAPIT registered, registration 64777, and serves London and just outside the M25.