One of the most practical questions when planning a garden office is power. You need it for your laptop, monitor, lighting, heating, and broadband. An extension lead from the back door might get you started, but it’s not a long-term solution.
Here’s everything you need to know about getting electricity to your garden office properly.
Why You Need Proper Electrics
Running an extension lead through a window or under a door works for occasional use but creates real problems as a permanent setup. Extension leads aren’t rated for outdoor permanent installation. They’re a fire and safety risk when used continuously. They’re also vulnerable to damage, trip hazards, and they look messy.
For a garden office you use regularly, a proper electrical installation is worth doing once and doing right.
The Legal Bit First
Electrical work that involves a new circuit from your consumer unit (fuse box) is classed as Part P work under Building Regulations in England and Wales. This means it must be carried out by a qualified electrician who is registered with a competent persons scheme (such as NICEIC or NAPIT) or inspected and certified by your local building control authority.
This isn’t bureaucracy for its own sake — it’s a safety requirement. Poorly installed garden electrics are a genuine fire risk. Use a qualified electrician.
Your Three Main Options
Option 1 — Extension lead (temporary only)
An outdoor-rated extension lead run from an existing outdoor socket. Fine while you’re waiting for proper installation or for very occasional use. Not suitable as a permanent solution. Limitations include cable length, trip hazard, no protection from weather damage, and it’s not rated for continuous high-draw use like heaters.
Cost: effectively free if you have an outdoor socket already.
Option 2 — Armoured cable (the standard solution)
Steel Wire Armoured (SWA) cable run from your house consumer unit to the garden office. This is what most people have installed and is the right long-term solution.
Armoured cable can be run above ground (along a fence line, for example) or buried underground. Above-ground runs need to be positioned where they won’t be damaged. Underground runs are neater and safer but involve more groundwork.
The cable connects to a small consumer unit (fuse box) inside the garden office, which then supplies sockets, lighting circuits, and heating as needed.
Cost: £1,500–£3,500 for a typical installation depending on cable run length and complexity.
Option 3 — Underground cable (most permanent)
Similar to Option 2 but with the cable buried at the correct depth (typically 450mm under a lawn, 600mm under a path or driveway). This is the neatest option and the most permanent. Requires more groundwork but results in no visible cables.
Cost: £2,000–£4,500 depending on length and ground conditions.
What a Typical Installation Involves
A standard garden office electrical installation includes:
Supply cable — SWA cable from your house consumer unit to the garden office. Your electrician will assess your existing consumer unit capacity and whether it needs upgrading.
Isolation switch — Usually at the house end, allowing you to isolate the garden office supply completely.
Garden office consumer unit — A small fuse box inside the office that protects individual circuits. Even a modest office typically has separate circuits for lighting, sockets, and heating.
Sockets — Most people want 6–8 double sockets. Think about your actual setup — desk area, equipment, kettle point.
Lighting circuit — Ceiling lights and possibly a switch-controlled outdoor light above the door.
Heating circuit — If you’re installing a fixed heater, it needs its own circuit. Electric panel heaters and infrared panels need a dedicated circuit rated for the load.
Earth bonding — Required for safety, especially in a timber structure.
Planning the Electrics Before the Building Arrives
The best time to sort the electrical supply is before or during the building installation, not after. Discuss this with both your electrician and your garden office supplier.
Key decisions to make in advance:
Where does the cable enter the building? Plan this with your supplier so the entry point is properly sealed and weatherproofed.
What route does the cable take? Mark out the route from house to office. If it’s going underground, the groundwork can happen while the base is being laid.
How many sockets and where? Think through your actual desk layout. More sockets now is cheaper than adding them later.
Is your existing consumer unit adequate? Your electrician will check this. Some older properties need a consumer unit upgrade before adding a garden circuit.
Questions to Ask Your Electrician
- Are you registered with NICEIC or NAPIT?
- What size cable do I need for my setup?
- Will my existing consumer unit support the new circuit?
- What’s included in your quote (cable, consumer unit, sockets, certification)?
- Will you provide an Electrical Installation Certificate on completion?
- Can you also install an outdoor light above the door?
Get at least two quotes. The cheapest isn’t always the best — for electrical work, qualifications and certification matter.
Broadband and Internet
You also need to think about internet connectivity. Options include:
Ethernet cable — Run a Cat6 cable from your home router to the garden office alongside the electrical cable. This gives you the fastest and most reliable connection. Cost is minimal — just the cable and a wall socket at each end. The best option if you’re doing the cable run anyway.
WiFi extender or mesh node — A wireless extender placed in the house pointing toward the garden office, or a mesh WiFi node mounted outside. Works reasonably well for moderate distances. Performance degrades with distance and obstacles (walls, trees). Cost: £50–£200.
Powerline adapters — Transmit internet signal through your electrical wiring. Can work well or poorly depending on the quality of your wiring. Cost: £40–£100. Less reliable than ethernet.
4G/5G router — A dedicated mobile broadband router in the garden office. Cost: £50–£150 for the router plus a monthly data SIM. Good backup option but running costs add up.
For full-time working, run an ethernet cable. The reliability difference versus WiFi is significant when you’re on video calls all day.
Common Mistakes
Leaving it until after the building is installed — Much harder to get cable runs right once the building is in place and landscaping is done.
Underestimating socket numbers — People consistently install too few sockets and regret it immediately.
Not planning for heating — A heating circuit needs to be specified from the start. Adding it later costs more.
Using an unqualified electrician — No certificate means no proof the work is safe, and potential problems when you sell the property.
Forgetting the internet — It’s easy to focus on power and forget connectivity. Run the ethernet cable at the same time as the electrical cable.
Cost Summary
| Installation type | Typical cost |
|---|---|
| Above-ground armoured cable, basic setup | £1,500–£2,500 |
| Underground cable, standard setup | £2,000–£3,500 |
| Adding ethernet cable at same time | £100–£300 extra |
| Consumer unit upgrade at house | £500–£1,500 extra if needed |
Get the electrical certificate when the work is complete and keep it with your property documents. You’ll need it if you ever sell.