Outdoor Sockets and Garden Power — A Homeowner's Guide
Lawnmowers on extension leads through kitchen windows: the tradition that keeps electricians busy. Here's how to do garden power properly.
Why outdoor sockets beat extension leads
An extension lead through a window works until it doesn't: trapped cables, overloaded reels, connections in the rain, and no guarantee of RCD protection between a faulty mower and your hands. A properly installed outdoor socket is weatherproof, RCD-protected, always where you need it — and surprisingly affordable.
A double outdoor socket spurred from a suitable indoor circuit typically costs £150–£300 installed. Sockets further from the house, or several positions around the garden, are usually served better by a dedicated outdoor circuit — typically £350–£600 depending on the routes.
What a compliant installation looks like
The specification matters more than the socket brand:
- 30mA RCD protection — non-negotiable for anything outdoors; it's what saves you when a cable gets cut
- IP-rated accessories — IP66 sockets with covers that seal around plugs in use, not just when closed
- Correct cable for the route — SWA (armoured) cable for buried runs at proper depth with marker tape; UV-resistant containment for surface runs
- Sensible positioning — near where you actually work: by the shed, the patio, the pressure-washing spot, not just beside the back door
- Capacity thinking — if a hot tub, EV charger or garden office is even a possibility, plan the supply once instead of digging twice
Powering sheds, studios and garden offices
Garden buildings deserve better than a socket on a spur. A garden office running heating, lighting, computers and a kettle needs its own sub-main: SWA cable from the house consumer unit to a small consumer unit in the building, with its own RCBOs for the building's socket and lighting circuits. That's a new circuit — notifiable under Part P — and it's the difference between a garden office that just works and one that trips the house every winter morning.
Typical costs run £800–£1,500 depending on distance, digging and the building's load — worth pricing while the groundworks contractor is still on site, because trenching is the expensive part.
Notifiable or not?
Adding one outdoor socket as a spur from an existing circuit: not notifiable (but must meet BS 7671, and outdoors is a special location — get it done competently). A new outdoor circuit, or any supply to an outbuilding: notifiable, and must be certified. We handle both across London and Kent with fixed pricing and NAPIT self-certification — call 07535 810812.
Frequently Asked Questions
How much does it cost to install an outdoor socket?
A double weatherproof socket spurred from a suitable indoor circuit is typically £150–£300 installed. A dedicated outdoor circuit serving multiple positions typically runs £350–£600. Supplies to garden buildings start around £800 depending on distance and groundworks.
Can outdoor sockets stay safe in the rain?
Yes — modern IP66-rated outdoor sockets are designed for permanent weather exposure, including covers that keep the connection sealed while a plug is in use. The RCD protection behind them is the second layer of defence.
Can I run power to my shed along the fence?
Surface-run SWA clipped along a solid fence or wall can be acceptable; draped flex and extension leads are not. Buried SWA at proper depth is the tidiest and most durable route. Either way, an outbuilding supply is a new circuit and needs certification.
Talk to a NAPIT-Registered Electrician
Call 07535 810812 or WhatsApp us — free quotes, honest advice, and certified work across London & Kent.