Electrics for Garden Rooms, Sheds & Garages

Garden offices, studios, gyms, workshops and garages all end up needing power. Running a supply out of the house is straightforward when it is planned properly, and risky when it isn't. We size the supply for the loads you expect, route it safely across the garden and give the building the protection it needs.

Start with how the building will be used

A shed with a light and one socket for a lawnmower charger needs very little. A garden office with a heater, computer and kettle needs much more, and a workshop with power tools or a garage with an EV charger more again. We ask what you plan to run, now and later, because the cable going out is the hardest part to change afterwards.

Armoured cable and routes

The supply is usually steel wire armoured cable, which is tough enough to bury. It runs in a trench at a safe depth with warning tape above, or along a wall or fence where that suits the route better. Clipping a cable along a fence needs care to keep it out of reach of strimmers and hedge trimmers. We agree the route with you, avoiding areas likely to be dug, and record where it goes. If you are building a path or patio, laying a duct before it is finished saves trouble later.

Sub-board or dedicated circuit

Small outbuildings can be fed from a dedicated circuit in the house consumer unit, ending at a socket and light. Larger garden rooms usually get a small sub-board in the building, fed from the house, with separate circuits for sockets, lighting and heating. That keeps faults isolated and lets you switch the building off in one place. If the house board has no spare capacity or lacks modern protection, a consumer unit upgrade may be needed first.

RCD protection

Circuits supplying outbuildings and outdoor equipment need RCD protection, which cuts the power quickly if current leaks to earth, for example through damaged cable or a person. That protection might be at the house board, at the sub-board or both, arranged so one fault doesn't trip everything.

Earthing arrangements

How an outbuilding is earthed depends on the supply to the house and on the building itself. In some cases the house earth is carried out with the cable; in others, particularly with certain supply types or metal-framed buildings, a separate earth electrode at the outbuilding is the right choice. We assess the arrangement on site and design to suit, in line with current wiring regulations.

Sockets, lighting and heating

Inside, we plan sockets around the desk or bench, lighting for the whole room, and a suitable supply for heating or air conditioning. Outside, a light by the door and an outdoor socket are popular additions. For path and garden lighting on the way out, see our outdoor lighting page.

EV charging

If the garage or a parking space near the outbuilding is where you will charge a car, the supply must be sized for it from the start, as a charger draws a high load for hours. Our EV charger installation page explains what we check before advising.

Working with garden room suppliers

Many garden rooms arrive as a kit or are built by a specialist installer. We can coordinate with them on cable entry points, internal positions and timing, so first fix happens before the interior lining goes on.

Testing and paperwork

Once connected, every circuit is tested and you receive an Electrical Installation Certificate. A new circuit from the house is notifiable work under the Building Regulations for England, and we explain the paperwork when we quote.

Talk to us

Adtec Electrical Services Ltd works from Lyford Business Centre near Wantage. Call 01235 430442, Monday to Friday, 7:30am to 5:30pm, or send the form with the building size and distance from the house. See the areas we cover.