Where to Fit a Consumer Unit: Practical Guidance for Safe, Accessible Installations
Finding the “right spot” for a new consumer unit is something we drill into every group on the advanced electrician courses at Elec Training Birmingham. Get it wrong and the board ends up hidden behind boxes in a cupboard: get it right and the homeowner can isolate a fault in seconds. Below is a deeper look at location, height, and environmental checks you should make before fixing the first screw.
1 Plan for easy, safe access
A consumer unit must be reachable without ladders or awkward stretching. Why? Because house-holders need to reset an RCD quickly, and electricians must open the cover for testing every five years. Approved Document M of the Building Regulations calls this “reasonable provision” for building users, with switches and outlets no higher than 1200 mm and no lower than 450 mm above finished floor level .
Quick checklist before choosing a wall:
Item | Minimum space needed |
Clearance in front of cover | 600 mm clear floor area |
Side clearance (hinge side) | 150 mm for lid swing |
Lighting | 150 lux recommended so labels are readable |
Location must also respect BS 8300 for disabled access: in a home with a resident who uses a wheelchair, mount switches between 1350 mm and 1450 mm so they can be reached while seated yet remain out of reach of small children.
2 Avoid hostile environments
Damp porches, loft spaces that hit 40 °C in summer, or dusty workshops all shorten component life. The IET recommends:
- Temperature: keep kit between –5 °C and +35 °C.
- Ingress: IP31 minimum indoors, IP55 if unavoidable outdoors.
- Sunlight: UV degrades plastic tails guards, so shield direct sun.
Where outdoor siting is unavoidable, specify a board with an IP-rated GRP enclosure and fit a drip shield over the door. Remember to derate protective devices by 5 % per 10 °C rise above 30 °C.
3 Height: balancing safety and usability
- Existing dwellings: no specific legal height, but most installers aim for main switch at 1400 mm.
- New builds (England & Wales): Document P notes that following Part M means fixing the main switch between 1350 mm and 1450 mm.
- Children’s bedrooms or playrooms: raise the board so young hands cannot reach live busbars during maintenance.
If relocating a board in a retrofit, always label the old tails route or remove it entirely to avoid future confusion, something many electricians forget.
4 Space, cabling and future expansion
Leave at least 20 % spare ways in domestic boards: one EV charger or a heat-pump circuit can fill three modules fast. Routing tails neatly with 25 mm² singles, not twin-wall conduit, makes the next upgrade simpler. You should allow a 50 mm bending radius at the meter end to avoid ETSI stress on the meter blocks.
5 Special situations that need Part P sign-off
Scenario | Extra step |
Moving board >3 m from meter | Notify DNO for new tails fuse |
Board change in bathroom annex | Zone calculations, 30 mA RCD to all circuits |
Flats with communal meter room | Fit REC-seal head, provide local service isolator |
All consumer-unit relocations are notifiable work. A Part P registered spark is required, so homeowners should budget for Building Control fees if they plan to DIY. It is surprising how often that bit is forgotten.
6 Take-away for learners
Mounting height, free air around the lid, and weather protection sound mundane, yet mis-placing a board is a common snag on NVQ portfolios. The advanced pathway at Elec Training Birmingham lets trainees practise real installs on a demo wall before heading to site, so when you meet the inspector you can argue your case confidently.
Ready to refine those skills? Our next cohort starts soon: check course dates and join a class that shows you exactly where to fit a consumer unit, and why every millimetre counts.
