Outdoor sockets, shed supplies and garden lighting are the single most common source of earth-leakage tripping we see, especially after heavy rain or a frost. The physics is simple: moisture provides a path to earth, and the RCD is designed to notice exactly that.
Where the water gets in
Failed gaskets on outdoor sockets, unsealed glands on shed supplies, spike lights whose cable entry sits in a puddle, and joints buried in the ground without a proper enclosure. Weatherproof accessories are only weatherproof while the seal and the lid are intact.
Buried cable damage
Cable run to a shed or garden office should be armoured and buried at a sensible depth with marker tape, or otherwise protected. Where a previous installer used ordinary cable in a shallow trench, a garden fork finds it eventually. We can trace and test the run before deciding whether to repair or replace.
Preventive measures
Giving garden circuits their own RCBO stops a wet evening from taking out the kitchen. Beyond that, IP-rated accessories, glanded entries, and correctly specified armoured cable are what make an outdoor installation boring — which is what you want.
Common questions
- Can I just stop using the outdoor socket?
- Isolating it is a reasonable interim step, but the leakage may be in the cable rather than the outlet, so it still needs testing.
- Do garden lights need special cable?
- Anything buried or exposed needs suitable cable and protection — ordinary indoor cable is not acceptable outdoors.
- Can you power a garden office?
- Yes, with a properly sized armoured supply and its own small distribution board, tested and certified.
- Is it worth an RCBO for the garden?
- In our view, yes — it isolates seasonal faults to the circuit that causes them.
Tell us whether the tripping follows the weather — it is one of the fastest diagnostic clues we get.
Related guides
- RCD Will Not Reset: How to Find the CircuitAn RCD that will not stay in is holding back a live earth-leakage fault somewhere on its side of the board.
- Powering a Garden Office or OutbuildingA garden office is a small installation in its own right, not a long extension lead.
- Planning Outdoor and Garden LightingGood exterior lighting is mostly about restraint, direction and IP ratings.