Shed, Garage & Outbuilding Power
Professional shed and garage power supply installation by qualified electricians. SWA cable, mini consumer unit, lighting, and sockets. Qualified and insured.
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Shed, Garage & Outbuilding Power
Qualified electrician
Same-day service
Most jobs matched within hours.
Upfront pricing
Clear quotes before work starts.
Qualified pros
NICEIC & NAPIT registered.
Pay when done
Funds held until you're happy.
How it works
Survey and requirements assessment
Your electrician visits to assess what you need power for in the outbuilding — lighting, sockets, power tools, heating, or a combination. They check the house consumer unit capacity, plan the cable route from the house to the outbuilding, and determine the size of supply needed.
Cable route and groundwork
A trench is dug from the house to the outbuilding at a minimum depth of 500mm. SWA (Steel Wire Armoured) cable is laid in the trench with warning tape above. The cable enters and exits each building through suitable glands. The trench is backfilled and the surface reinstated.
Outbuilding consumer unit installation
A small consumer unit (typically 4-6 ways) is installed in the outbuilding. This provides independent circuit protection with RCBOs for each circuit. The incoming supply from the house is connected via an isolator switch.
Circuit installation in outbuilding
Circuits are installed for lighting and sockets. A typical shed or garage gets one lighting circuit and one socket circuit. Workshops or garden offices may have additional circuits for high-power equipment. All wiring is surface-mounted in conduit or trunking.
Connection to house supply
The SWA cable is connected to a dedicated way in the house consumer unit, protected by a suitably rated RCBO. If the house consumer unit has no spare ways, a small henley block or additional enclosure may be fitted.
Testing and certification
Both the supply cable and the outbuilding installation are tested for insulation resistance, earth fault loop impedance, and RCD trip time. An Electrical Installation Certificate (EIC) is issued covering the complete installation, and the work is notified to Building Control.
What's included
What's involved
A dedicated power supply to a shed, garage, workshop, or garden office gives you proper lighting and socket outlets rather than running extension leads across the garden. The installation typically involves running SWA (Steel Wire Armoured) cable underground from the house consumer unit to a small consumer unit in the outbuilding, which then supplies lighting circuits and socket outlets with independent RCD protection. This is a self-contained electrical installation in a separate building, with specific requirements under BS 7671.
Supplying power to a separate building is notifiable work under Part P of the Building Regulations. It must be carried out by a qualified electrician registered with a competent person scheme. Running an extension lead from the house to a shed is dangerous — the cable crosses outdoor ground (trip hazard and damage risk), has no weatherproofing at the connection points, and is not protected by an RCD suitable for the outdoor environment. A permanent SWA cable supply with its own consumer unit is the safe, compliant, and reliable solution.
Get a personalised quote
Typical cost: £300–£1,000per installation
Every job is different — pricing depends on your property, location, and specific requirements. Describe what you need and a qualified electrician will quote you directly.
How long does it take?
One day for a garage or shed close to the house with a short cable run. One to two days for outbuildings further away, involving long trenches, hard surface crossings, or larger installations with multiple circuits.
Regulations & safety
Safety notice
Never run an extension lead from the house to a shed or garage as a permanent power supply. Extension leads are not rated for outdoor use, create trip hazards, and have no appropriate RCD protection for the outdoor environment.
SWA cable buried underground must be at minimum 500mm depth with warning tape above. Record the cable route accurately — future garden work (fence posts, tree planting, landscaping) could damage a buried cable if its route is unknown.
Outbuildings with PME earthing exported from the main house may require an earth rod. Your electrician will test and determine the correct earthing arrangement — this is a critical safety decision that affects shock protection.
Part P of the Building Regulations (Approved Document P)
Supplying power to a separate outbuilding is notifiable work involving a new circuit and a new installation in a separate structure. It must be carried out by an electrician registered with a competent person scheme.
BS 7671:2018+A2:2022 (IET Wiring Regulations), Section 704
Section 704 covers installations in construction and demolition sites, but the general principles for temporary/outdoor supplies apply. More relevantly, the requirements for separate buildings fed from another installation are covered in Chapter 55 (isolation and switching) and the general outdoor provisions of Section 714.
BS 7671 — Earthing Requirements for Separate Buildings
A separate building fed by SWA cable from the main house has specific earthing requirements. If the house has PME (TN-C-S) earthing, the outbuilding may require its own earth electrode (earth rod) under certain conditions, as PME earthing should not be exported to a separate structure without additional measures.
IET Guidance Note 7 — Special Locations
Provides guidance on electrical installations in outbuildings, including earthing arrangements, cable selection, and the specific considerations for structures detached from the main dwelling.
What to expect
Having issues with your existing installation?
Already have a shed, garage & outbuilding power and having issues? Check our troubleshooting guides.
Frequently asked questions
Can I run an extension lead to my shed instead?
Do I need a consumer unit in my shed or garage?
What is SWA cable and why is it needed?
Can I use my shed power supply for an electric heater?
Does my shed need its own earth rod?
How much does it cost to run power to a garden office?
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