Why does my outside socket trip the RCD – Advice from Electriman, North London Electricians

Why Your Outside Socket Keeps Tripping the RCD

An RCD (Residual Current Device) is a safety switch in your consumer unit (fusebox) that cuts power within milliseconds when it detects electricity leaking to earth — the kind of leak that can kill. When your outdoor socket causes it to trip, that is the RCD doing exactly what it should.

What causes it?

Moisture or water inside the socket — outdoor sockets must be IP-rated (weatherproof), and if the cover is cracked, missing, or left open in rain, water gets in and creates a leakage path to earth

A faulty appliance — a lawnmower, pressure washer, or extension lead with damaged insulation will cause an immediate trip

Damaged cable — the cable feeding the outdoor socket may have been cut by a spade, gnawed by rodents, or degraded over time

A loose or corroded connection — connections inside the socket box can corrode outdoors, especially if the socket is not properly sealed

Wiring fault from a previous DIY job — non-compliant wiring installed without proper protection or the correct cable type

What you can safely check yourself

1. Unplug every appliance from the outdoor socket

2. Go to your consumer unit and reset the RCD

3. If it stays on, plug appliances back in one at a time to identify the faulty one — discard or have it repaired

4. If it trips immediately with nothing plugged in, there is a wiring or socket fault

5.

Need a qualified electrician in North London?

Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.