What is this?
Outdoor sockets are exposed to the UK weather and are particularly vulnerable to water ingress. When moisture gets into the socket enclosure or the cabling, it creates an earth fault that trips the RCD. This is a common and potentially dangerous fault, especially if the socket is not correctly rated for outdoor use (IP65 or above).
Common causes
- Damaged or missing weatherproof cover on the outdoor socket
- Degraded IP-rated enclosure letting rain in through cracks or broken seals
- Water tracking along the cable entry point into the socket back box
- Condensation building up inside the enclosure over time
- Incorrect socket type installed — indoor socket used outside
Is it dangerous?
Yes, this is a serious safety risk. Water and electricity are a dangerous combination. If an outdoor socket has water inside it, there is a real risk of electric shock — especially if someone touches it while standing on wet ground. The RCD tripping is doing its job protecting you, but the underlying fault must be fixed. Never attempt to use a wet outdoor socket.
Can I fix it myself?
Do not attempt to open or dry out the socket yourself while it is connected to the supply. You can visually check whether the weatherproof cover is damaged, missing, or not closing properly. If the cover has simply blown open and the socket looks dry inside, closing the cover and resetting the RCD may resolve it temporarily. However, if moisture has entered the socket, you need a professional.
When to call an electrician
Call an electrician if the socket trips every time it rains, if you can see moisture or corrosion inside the enclosure, if the existing socket does not have a proper weatherproof cover, or if it was not installed on its own RCD-protected circuit. Outdoor socket installations must comply with BS 7671 and usually require Part P notification.
What will an electrician do?
Isolate the circuit and inspect the outdoor socket for water ingress and corrosion
Test the circuit insulation resistance to check for moisture damage in the cabling
Replace the socket with a correctly rated IP65 or IP66 weatherproof unit
Ensure proper cable entry seals and drainage to prevent future water ingress
Verify the circuit has dedicated RCD protection (30mA) as required by regulations
Issue a Minor Electrical Installation Works Certificate for the repair
Typical cost
£100 – £250
Replacing an outdoor socket with a properly rated IP65 unit including labour. A new outdoor circuit from the consumer unit will cost more (typically £250–£450).
