A garage with a proper electrical supply is a fundamentally different space from one without. Whether you want a workshop, home gym, home office or simply somewhere to charge your EV, here's what providing an electrical supply to a garage involves.
Attached vs Detached Garage
Attached garage — shares a wall with the house. Cables can typically be routed through the wall directly, making installation simpler and cheaper.
Detached garage — requires an underground cable run from the house. This involves digging a trench, laying armoured cable at the correct depth (typically 600mm under a lawn, 500mm under a path), and reinstatement. It's more involved but the results are permanent and reliable.
What Supply Do You Need?
The right supply depends on what you want to power:
Light use (lighting, sockets for tools, phone charging) — a 32A supply from your existing consumer unit, with a small consumer unit or fuse board in the garage, is typically sufficient.
EV charger — a dedicated 7kW EV charger requires a dedicated 32A circuit. If you also want general sockets and lighting, either run two circuits from the house or install a sub-board in the garage.
Workshop with 240V power tools — a 32A supply is usually adequate for most home workshops. If you have three-phase equipment, discuss this with your electrician.
Heavy equipment (welder, compressor) — may require a higher-rated supply or a second circuit.
Sub-Consumer Unit in the Garage
For any supply beyond a single circuit, fitting a small consumer unit (sub-board) in the garage is the right approach. This gives you:
- Individual circuit protection for each use (lighting, sockets, EV charger)
- A local isolation point (turn off all garage electrics at the board)
- Capacity for additional circuits in the future
Cable Types for Underground Runs
Underground cables must be armoured (steel wire armoured — SWA) or protected in rigid conduit. The cable type and size will be specified by your electrician based on the required load and cable run length.
Part P Compliance
Installing a supply to a detached garage or outbuilding is notifiable under Part P. The work must be carried out by a registered electrician and certified.
Onyx Electrical Solutions installs electrical supplies to garages and outbuildings across Greater Manchester. Call 07000 000000 for a free site visit and quote.