A garage consumer unit (often still called a garage fuse board) is a small distribution board that feeds the lighting, sockets and tools in a garage or outbuilding. You need one when the garage has more than a couple of circuits, runs power tools or an EV charger, or is likely to grow. A single light and socket can sometimes be fed straight from the house instead. Either way, the work has to meet BS 7671, and it should be done, tested and certified by a competent electrician.
This guide explains when a separate board makes sense, what to look for in the unit itself, what the rules say, what it typically costs and what a good installation looks like. We are an electrical contractor covering Dorset, Hampshire and Devon, so we also say where we see garages go wrong.
TL;DR
- A garage consumer unit is a small board that splits power into separate protected circuits. It is worth having once you want lighting, sockets, tools, a charger or room to expand.
- Look for a unit that meets BS EN 61439-3, has a non-combustible enclosure and an enclosure rating suited to a damp or dusty garage. Cheap or counterfeit boards are a real fire risk.
- A like-for-like board swap is commonly quoted at £220 to £475. A new supply to a detached garage with a long cable run can reach £1,000 to £2,500 or more.
- This is not a DIY job. It needs design, inspection, testing, an Electrical Installation Certificate and, where required, notification.
- Plan for the load you will have in five years, not today’s: a workshop, a heat pump or an EV charger changes the sums.
Table of Contents
- What a garage consumer unit actually does
- Do you need a garage consumer unit?
- Garage fuse board vs consumer unit: is there a difference?
- What protection and enclosure should it have?
- Choosing a safe unit
- What needs checking before the board is chosen
- UK rules: BS 7671, Building Regulations and certificates
- Can you fit a garage consumer unit yourself?
- How much does a garage consumer unit cost?
- Garage consumer unit and an EV charger
- Garage boards, solar and batteries
- Our view on garage boards
- Getting your garage done properly
- FAQ
- Sources
What a garage consumer unit actually does
A consumer unit takes one incoming supply and divides it into final circuits, each with its own protective device. If a drill motor fails or a cable is nicked by a spade, only that circuit trips and the rest of the garage keeps working. The unit also holds the protection that guards you against electric shock.
According to Voltimum’s UK installation guide, a garage board is needed when the space requires multiple circuits, significant power for machinery, or spare capacity for later. It also notes that very basic setups may not need one.
In practice, a typical small garage board has two to five ways:
- a lighting circuit, usually protected at 6A
- a socket circuit, usually protected at 16A or 20A
- optionally a circuit for a workbench, compressor, freezer or heater
- a spare way for later additions
The board in the garage is normally fed by a cable from the main consumer unit in the house, or from a separate supply point if the garage is a long way from the property.
Do you need a garage consumer unit?
Not always. It depends on what the garage will be used for.
You can often manage without one when:
- the garage is attached or very close to the house
- you only need one light and one socket
- the design can be fed from a dedicated circuit in the house board
The Institution of Engineering and Technology (IET) says that simple outbuildings can be served from a dedicated circuit from the dwelling’s consumer unit, and that the designer must still meet every BS 7671 requirement, including protection against shock and fire.
You should plan a separate board when:
- the garage is detached, or the cable run is long
- you want several circuits (lights, sockets, tools, heating)
- you are converting the space into a workshop, gym, home office or utility area
- you plan to add an EV charger now or later
- the house board has no spare ways
The IET’s own example for a small outbuilding is a spare way in the house unit feeding a two-way board in the garage, with a 6A breaker for lights and a 16A breaker for sockets. That is a neat, inexpensive arrangement, and it shows how modest a garage board can be.
Garage fuse board vs consumer unit: is there a difference?
No practical difference for you. “Fuse board” is the older name, from the days of rewireable fuses. Modern boards use miniature circuit breakers (MCBs), residual current devices (RCDs) and combined units called RCBOs. When someone asks for a garage fuse board today, a garage consumer unit is what an electrician will fit.
If your garage still has a ceramic fuse board, it is overdue for inspection. Old boards often lack RCD protection, which matters a great deal in a space where you use power tools, extension leads and damp floors.
What protection and enclosure should it have?
RCD protection
Sockets that may supply portable equipment outdoors need RCD protection with a rated residual operating current not exceeding 30mA. The IET guidance on supplying an outbuilding says this can be provided, for example, by an RCBO in the house consumer unit.
Most electricians now prefer RCBOs on each garage circuit. A fault on the lights then does not knock out the sockets, and you are not left in the dark in a workshop with a spinning blade.
Non-combustible enclosure
Voltimum notes that BS 7671 favours a non-combustible enclosure for consumer units in domestic installations. A metal-clad board is the usual answer. It also resists knocks from ladders, bikes and car doors much better than thin plastic.
Ingress protection (IP rating)
The enclosure must suit the environment. The same guide says certain indoor units are only IP2XC, and that damp or outdoor locations need an appropriate enclosure. Garages are rarely dry all year: condensation, wet coats, pressure washers and open doors all play a part. For a garage with damp walls, a dusty workshop or an outbuilding exposed to the weather, we would specify a higher-rated enclosure. Never put a standard indoor board in a damp outbuilding because it was cheaper.
Overload protection for the main switch
The main switch and RCCB within a consumer unit must have overload protection, typically from an upstream fuse-link, unless the designer decides they cannot be overloaded, as set out in the BEAMA safety checklist for consumer units. This is design detail that your electrician handles, but it is one reason a boxed board from a trade counter is not the whole job.
Choosing a safe unit
Distribution boards intended for use by ordinary persons should conform to the BS EN 61439 series, according to Voltimum. BEAMA warns that non-compliant or counterfeit consumer units can pose significant fire and electrocution risks, and stresses choosing products that meet BS EN 61439-3.
A quick checklist before you accept any board, whoever supplies it:
| Check | What good looks like |
|---|---|
| Standard | Marked as meeting BS EN 61439-3 |
| Enclosure | Non-combustible (metal) for a domestic setting |
| Environment | IP rating suited to damp, dust or outdoor exposure |
| Protection | 30mA RCD protection on sockets; RCBOs on each circuit are preferred |
| Capacity | At least one spare way beyond today’s needs |
| Source | A known trade supplier, not an unbranded online listing |
A very low price on an unbranded board should make you cautious. Your electrician takes responsibility for what goes into the installation, so ask which brand and model is being fitted, and why.
What needs checking before the board is chosen
The board is the easy part. According to the same Voltimum guide, an electrician should assess the total load, existing supply capacity, cable size and route, earthing arrangements, and any need for special moisture or impact protection.
In plain terms, that means:
- Load. What will run at the same time? A compressor, a welder and a heater together draw far more than a few LED lights.
- Spare capacity at the house. If the main unit is full or the supply is already stretched, the garage may need a different arrangement.
- Cable size and route. Long runs need larger cable to keep voltage drop in check. Buried armoured cable needs the right depth and protection. Overhead runs have their own rules.
- Earthing. The method of earthing depends on the existing installation and whether the garage has metal pipes or other conductive parts. The IET guide flags that a metal water pipe into a garage needs particular attention, and that the existing installation’s earthing and bonding should be verified first.
- Environment. Damp, impact and dust all affect enclosure choice and where the board is mounted.
A contractor who quotes without asking about any of this is guessing.
UK rules: BS 7671, Building Regulations and certificates
Installations should comply with BS 7671 and the applicable Building Regulations. Per Voltimum, new garage submains and consumer units generally need an Electrical Installation Certificate, and notification requirements differ across the UK.
In England and Wales, Part P of the Building Regulations covers electrical safety in dwellings and extends to garages and outbuildings attached to homes. New circuits and consumer unit replacements are generally notifiable, which means the work is either self-certified by an installer registered with a competent person scheme or notified to building control. Scotland and Northern Ireland have their own systems, so check the position for your nation.
What this means for you:
- Ask for the Electrical Installation Certificate when the job is finished and keep it. You will need it when you sell, and your insurer may ask for it.
- Ask how the work will be notified or self-certified. A registered installer handles this for you.
- If you are a landlord, a garage that forms part of the let property should be included in the inspection cycle. Our guide to the EICR deadline and compliance checklist for landlords explains the process.
Can you fit a garage consumer unit yourself?
We would advise against it. Voltimum’s guide says this is not normally an appropriate DIY project: it should be completed by a suitably competent electrician, then inspected, tested, certified and notified where required. See that guidance for the full picture.
The reasons are practical rather than bureaucratic:
- Isolating the house supply and working inside a live main unit carries a real risk of shock.
- Choosing the right protective device for the cable and the load needs design knowledge.
- Without proper testing (earth fault loop impedance, insulation resistance, RCD trip times) you cannot know that the circuit will actually protect you in a fault.
- Uncertified work can cause trouble with building control, insurance and house sales.
You can still save money legitimately. Clear the garage, mark where you want sockets and lights, and agree the plan before the electrician arrives. That shortens the job.
How much does a garage consumer unit cost?
Costs vary widely with the cable run and ground conditions. The Voltimum guide gives these ranges:
| Job | Typical quoted range |
|---|---|
| Like-for-like board swap, no cabling issues | £220 to £475 |
| Detached garage supply with excavation or a long cable run | £1,000 to £2,500+ |
These are ranges from the Voltimum UK guide, not our own prices. We do not publish fixed prices for this work because the cable route, the state of the house board and the finish you want change the figure so much. We quote after we understand the site.
What drives the price up or down:
- Distance from the house. Every extra metre of armoured cable and trench adds labour and material.
- Ground. Lawn is easy; concrete, patios and tree roots are not.
- State of the house board. If it is old, it may need replacing before it can safely feed anything new.
- Number of circuits. More ways, more RCBOs, more cost.
- Extras. External lighting, data cables, a heater or an EV charger.
When you compare quotes, check that each one includes testing, certification, notification and making good, not just the board.
Garage consumer unit and an EV charger
Many of the garage jobs we are asked about now start with a charger. A charger is a heavy, continuous load, often 7kW on a dedicated circuit, and it should be designed in from the start rather than squeezed into a spare way. Whether the garage board can carry it depends on the supply, the cable and the other loads on site.
If you are considering one, read our guide to EV charger load balancing and avoiding grid reinforcement, then look at our EV charger installation service. Sorting out the garage board and the charger in one visit usually saves a second trip and a second set of paperwork.
Garage boards, solar and batteries
A garage is a popular place for a battery or inverter because it is out of the way. If you have solar panels or are planning them, the board choice affects how easily you can add generation and storage. We explain the issue in our guides to a solar-ready consumer unit and a solar fuse box upgrade. Designing for it now means you will not have to replace the board again later.
Our view on garage boards
We fit a lot of garage and outbuilding supplies across Dorset, Hampshire and Devon. Coastal air, damp older garages and detached outbuildings at the end of long gardens are common here, and they all push us towards sturdier enclosures and careful cable choices.
Here is what we tell customers:
- Fit for the next ten years. The extra cost of a spare way or two is small compared with reopening trenches later.
- Think about what is coming. Solar, a battery, a charger or a heat pump all change the picture. We design the garage supply with them in mind.
- Test everything. A tidy installation that has not been tested properly is only tidy. Testing is where problems show up, so we do it on every job.
- Leave it clean. Cable runs mean mess. We take care to leave sites tidy.
We are MCS and NICEIC accredited, and customers can read our 4.9 Trustpilot rating for themselves. We think the best way to judge an electrician is to ask them the questions in this article. If the answers are specific, you are in good hands.
— Simon
Getting your garage done properly
If you are planning a new garage supply, a board replacement or a larger project that includes solar, a battery or an EV charger, we can look at the whole installation together. We cover residential and commercial properties across Dorset, Hampshire and Devon, and we can also carry out electrical testing on existing installations.
Tell us about your garage, the cable route and what you want to run, and we will explain the options before you commit. Start on our home page to get in touch, or see our solar installation and EV charger pages if the garage is part of a bigger plan.
FAQ
Do I need a garage consumer unit?
Only if the garage needs several circuits, significant power or room to grow. A single light and socket can sometimes be fed from a dedicated circuit in the house board, as the IET guidance describes. For a workshop, a detached building or anywhere you may add a charger, a separate board is the sensible choice.
Is a garage fuse board the same as a consumer unit?
Yes, in everyday use. “Fuse board” is the older term. A modern garage board uses MCBs, RCDs or RCBOs rather than rewireable fuses. If your garage still has old fuses, ask an electrician to inspect it.
How much does it cost to put electricity in a garage in the UK?
A like-for-like board swap is commonly quoted at £220 to £475, while a detached garage with excavation or a long cable run may cost £1,000 to £2,500 or more, per the Voltimum guide. Your own figure depends on distance, ground and the number of circuits. A site visit gives the most reliable quote.
What enclosure should a garage consumer unit have?
A non-combustible enclosure, usually metal, is the norm for domestic units, and its IP rating should match the conditions. Damp, dusty or outdoor locations need more protection than a standard indoor board. Your electrician should choose this after seeing the space.
Can I install a garage consumer unit myself?
It is not normally an appropriate DIY project. It should be done by a competent electrician, then inspected, tested, certified and notified where required, according to Voltimum. A certificate protects you when you sell or claim on insurance.
Sources
- How to Wire a Garage Consumer Unit: UK Installation Guide, Voltimum
- Electrical installations outdoors: a supply to a detached outbuilding, IET
- Safety checklist for consumer units, BEAMA
- Notifiable electrical work and Part P
