Wiring a Garage: Power, Lights & Consumer Units

A garage without electrics is a frustrating space, fine for storing boxes, but limited for anything else. Adding a proper electrical installation turns a garage into a workshop, gym, home office, or EV charging point. Most UK homeowners budget between £800 and £2,500 for a competent installation, though the total depends heavily on how far the garage sits from the house consumer unit and how many circuits you need.

All domestic electrical work in England and Wales should follow BS 7671 and, where notifiable, be certified under Part P of the Building Regulations. BS 7671, the IET Wiring Regulations, is currently the 18th Edition as amended in 2026 (BS 7671:2018+A4:2026).¹ Scotland has no Part P: electrical work there must meet Standard 4.5 of the Scottish building standards, under the building warrant system.² This is not a grey area, an unregistered installation will cause problems when you sell the property and, more importantly, poses a genuine safety risk.

Typical Cost Breakdown

For a typical detached garage 8–15 m from the house, a realistic job, armoured cable run, 6-way consumer unit, one ring/radial socket circuit, and a lighting circuit, comes to roughly £750–£1,950 at the rates in the table when installed by a qualified electrician.

If the garage is integral to the house (sharing a wall), the run is shorter and costs drop to the lower end; a detached garage at the far end of a 30 m garden will sit at the top end or beyond.

What Cable to Use: Armoured vs SWA

For an underground run from house to detached garage, the standard cable is SWA (steel wire armoured), usually three-core and commonly 6 mm² or 10 mm² for a garage supply, with the size set by the electrician from the load, the length of run and voltage drop. BS 7671 requires a cable buried in the ground to have an earthed armour or metallic sheath, or to run in a suitable duct, and its route to be marked with cable covers or marker tape.³ It sets no fixed burial depth: the cable must be deep enough to avoid damage from any reasonably foreseeable disturbance of the ground, and the IET says a depth of less than 0.5 m is usually inadvisable.⁴ Go deeper where the route crosses a drive or ground likely to be dug. The steel armour protects the cable from accidental damage during future digging.

Overhead cable runs are also permitted, but the cable must be properly supported, usually on a catenary wire, and kept well clear of head height, with more clearance over any drive; the span and sag must be calculated to avoid mechanical failure. Most electricians prefer underground runs for neatness and safety.

An alternative to SWA is an unarmoured cable in a buried duct that gives equivalent protection against mechanical damage. Ducts rated N450 or N750 under BS EN 61386-24 are intended to be buried directly in the ground without additional precautions.³ SWA is still the more common choice for a garage supply.

Sub-Consumer Unit Requirements

Every properly wired garage should have its own small consumer unit (also called a distribution board or sub-board). This serves three purposes:

1. Provides local overcurrent protection for each circuit
2. Allows isolation of the garage without affecting the house supply
3. Provides RCD or RCBO protection as required by BS 7671

Since 1 January 2016, BS 7671 has required a consumer unit in domestic premises to have a non-combustible enclosure, in practice usually steel, or to sit inside a non-combustible cabinet; the rule came from Amendment 3 to the Wiring Regulations, not from the Building Regulations.⁵ The IET says the rule was meant to cover a garage or outbuilding that is integral to, attached to or close to the house, so a metal sub-board is the safe default; for a detached garage further away it is a judgement based on the fire risk to the house.⁵

A 4–8 way split-load or RCBO consumer unit from a reputable manufacturer (Hager, Schneider, Wylex, MK) costs £60–£150 for the unit itself; installation including wiring in is the bulk of the labour cost.

Lighting Options

For a garage used as a workshop, good lighting is critical. Options in 2026:

• LED batten lights, cool white (4,000 K) to daylight (6,500 K); most cost-effective. A 4 ft twin LED batten (£20–£50) typically gives 3,300–5,000 lm depending on model. LAP’s Oxbo twin 4 ft batten, for example, is rated at 4,400 lm of 4,000 K light.⁶ Two to four fittings suit most double garages.
• LED panel lights, Neater in appearance; better for home offices or gyms.
• High-bay LED, For garages over 3 m ceiling height; not usually needed for domestic.

Switching: a single PIR sensor at the door is convenient for everyday use; a conventional switch is needed if the garage is used as a workshop where constant-on lighting matters. A simple dual switching arrangement (manual or PIR) is easy to wire into the same circuit.

External lighting, a PIR floodlight or wall lantern above the garage door, is typically added to the same lighting circuit or a separate spur.

Sockets and Workshop Circuits

For a workshop, plan socket numbers generously, you will always want more than you expect. Building Regulations do not mandate a minimum socket count in a garage, but a practical layout is:

• One 4-gang socket on each wall (or 2-gang doubles at multiple locations)
• A dedicated 32A radial circuit for a welder, compressor, or large workshop machine
• Sockets at bench height (900–1,000 mm) rather than floor level

For EV charging, a dedicated 32A circuit and Type 2 wall box (£800–£1,200 installed) is the correct approach, never charge an EV from a standard 13A socket long-term. The government’s home chargepoint grants now cover only flat owners, renters, landlords and homes with on-street parking, so a homeowner charging in their own garage should not expect one.⁷

Part P and Certification

Under Part P of the Building Regulations, electrical installation work in a garage is notifiable if it involves:

• A new circuit from the house consumer unit⁸
• The replacement of a consumer unit (a new garage sub-board is fed by a new circuit, so it is notifiable either way)⁸
• An addition or alteration to an existing circuit in a special location, which Approved Document P defines as the space around a bath or shower (from floor level up to 2.25 m, and 0.6 m out from the edge of the bath or shower tray, or 1.2 m from the centre of the shower head where there is no tray) or a room containing a swimming pool or sauna heater⁸

Those three are the only notifiable jobs. A garage is not a special location, however damp it is, so adding a socket or a light to a circuit that already serves the garage is not notifiable. In practice most garage projects are notifiable anyway, because they start with a new circuit from the house or a new sub-board. A registered competent person can self-certify their own work: for electrical installations in homes the government-authorised schemes are BESCA, Blue Flame Certification, Certsure (NICEIC), NAPIT and OFTEC.⁹ Within 30 days of finishing, the installer must give you a certificate of compliance and notify the local authority, which the scheme usually does on their behalf.¹⁰ They should also give you an Electrical Installation Certificate (EIC) under BS 7671. Keep both: they are the documents a buyer’s solicitor will ask for when you sell.

If notifiable work is done by someone who is not registered, including DIY, it must be notified to Building Control before work starts or certified by a registered third party.⁸ Work done without either can only be put right afterwards by applying to the local authority for a regularisation certificate, a more expensive and uncertain process that usually starts with an EICR from a registered electrician.¹¹ Do the job right first time.

Useful Checks Before Hiring

• Ask for the electrician’s competent person scheme registration number and verify it on the relevant scheme website (NICEIC Check, NAPIT Find a contractor). There is no such thing as a “Part P-registered” electrician: the category is a registered competent person⁸
• Confirm they will issue a full Electrical Installation Certificate on completion
• Check whether the quote includes a building control charge. It only arises if the electrician is not registered to self-certify, which is itself a red flag, and each council sets its own: Solihull, for example, charges £395 for a building notice for major electrical installation work.¹²
• For SWA cable runs, confirm the trench depth and route avoids other buried services (check your utility plans)

Getting the electrics right at the outset saves significant expense later, particularly if you plan to convert the garage or sell the property.