Updated
RCD Tripping When It Rains
Your electrics trip whenever it rains, suggesting water is getting into your electrical installation.
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What's happening?
When your RCD trips during or after rain, moisture is almost certainly getting into your electrical installation somewhere. Water is conductive and creates an earth leakage path that the RCD detects. This is a serious issue because the combination of water and electricity creates a significant risk of electric shock.
What usually causes it?
- Water ingress into an outdoor socket, light, or junction box with failed seals
- Damaged or deteriorated cable insulation on external wiring
- Leaking roof allowing water to drip onto light fittings or wiring in the loft
- Faulty damp-proof course allowing moisture into sockets on external walls
- Condensation in an outbuilding, shed, or garage with poor ventilation
- Underground cable to a garden building with damaged sheathing
Is it dangerous?
This is a high-risk situation. Water and electricity are a dangerous combination, and the fault will likely worsen with each episode of rain. The RCD is protecting you from a potentially lethal shock, but the underlying water ingress needs to be found and fixed urgently. There is also a risk of corrosion damage to wiring and fittings that could cause a fire.
Can I fix it myself?
Do a visual inspection of all outdoor electrical fittings including garden lights, external sockets, outbuilding supplies, and security lights. Look for obvious signs of water entry, cracked covers, or missing seals. Check the loft for water near any cables or light fittings. Do not open or touch any fitting that appears wet — isolate the circuit first.
When should you call an electrician?
Call an electrician as soon as possible. Rain-related tripping indicates water in the electrical installation, which is a serious safety issue. The problem will not fix itself and will get worse over time as water causes further corrosion and insulation breakdown. An electrician needs to find and seal the point of water ingress.
What will the electrician actually do?
- Systematically isolate circuits to identify which one is affected by moisture
- Inspect all outdoor and exposed fittings for signs of water ingress
- Carry out insulation resistance testing in both dry and wet conditions to pinpoint the fault
- Replace damaged fittings with appropriate IP-rated enclosures for outdoor use
- Repair or reroute damaged cables and restore weatherproof seals
- Recommend improvements such as IP65-rated outdoor sockets and proper cable entry grommets
What will it cost to fix?
£120–£300
Costs depend on the location and extent of water ingress. Replacing outdoor fittings and re-sealing is at the lower end. Rerouting cables or repairing underground feeds costs more.
Find an electricianFrequently asked questions
We’re happy to answer all your questions.
Why do my electrics only trip when it rains?
Rainwater is getting into your electrical installation somewhere, creating a path for current to leak to earth. The RCD detects this leakage and trips. Common entry points are outdoor sockets, garden lights, loft wiring near roof leaks, and cables to outbuildings.
Is it safe to reset the RCD after it trips in the rain?
You can try, but if it trips again do not keep resetting it. The water is creating a shock hazard that the RCD is protecting you from. Isolate outdoor circuits if possible and wait for the installation to dry out, but get an electrician to investigate.
Could a leaking roof cause my electrics to trip?
Absolutely. Water from a roof leak can drip onto cables, light fittings, and junction boxes in the loft. This is particularly common where downlighters penetrate the ceiling and water runs down the fitting into the room below.
Do I need special sockets for outside?
Yes. Outdoor sockets must be at least IP66 rated and protected by a 30mA RCD under BS 7671. They should have self-closing weatherproof covers. If your outdoor sockets do not meet these standards, they should be replaced.
Will silicone sealant fix a leaking outdoor socket?
Silicone is a temporary fix at best. The correct solution is to replace the fitting with a properly rated IP66 outdoor enclosure and ensure cable entries are sealed with proper grommets. An electrician can do this properly.
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