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 e very 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 f inished 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 s witches 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.
