Where to Fit a Consumer Unit

Finding the right spot for a consumer unit sounds basic, but you’d be surprised how many boards end up mounted next to the ceiling above a downstairs toilet where you can’t even get the steps near enough to reach it, or shoved so low in a cupboard that homeowners need to crawl on the floor to reset an RCD. Get the location wrong and you’re creating problems for the next decade. Get it right and the board’s accessible, s erviceable, and compliant. 

Here’s what you actually need to consider before fixing the first screw. 

Why Location Matters (And Why So Many People Get It Wrong) 

A consumer unit must be reachable without ladders, awkward stretching, or clearing out an entire cupboard of stored junk. Homeowners need to reset an RCD quickly when something trips. Electricians need to open the cover for testing every five years (or more often if there’s an issue). If the board’s mounted at 8 feet up because someone thought it looked neater near the ceiling, or tucked behind the tumble dryer because “that’s where there was space,” you’ve failed. 

BS 7671 requires that electrical equipment is arranged to afford accessibility for operation, inspection, testing, and maintenance (Regulations 131.12 and 513.1). That’s not a suggestion. It’s a requirement. Approved Document M of the Building Regulations calls this “reasonable provision” for building users, with switches and outlets between 450mm and 1200mm above finished floor level. 

For new builds in England and Wales, Part M specifically recommends fixing the main switch between 1350mm and 1450mm above floor level. That puts it at a height where most adults can reach it comfortably, but it’s high enough that small children can’t get to live busbars during maintenance. 

Where a resident uses a wheelchair, BS 8300 recommends mounting switches between 1350mm and 1450mm so they can be reached while seated. Same height range, different reason. It works. 

The Height Debate: What Actually Makes Sense 

There’s no specific legal height requirement for existing dwellings, but most installers aim for the main switch at around 1400mm. That’s become the de facto standard because it works for accessibility, it’s comfortable for most people to reach, and it keeps the board high enough that you’re not bending over to reset circuits. 

For new builds, Part M’s 1350mm to 1450mm range is the guidance. Stick to it. Don’t mount boards next to the ceiling (I’ve seen them at 2.15m, which is madness). Don’t m ount them next to the floor in a first-floor bedroom (yes, that happened on a job where an electrician moved an outside consumer unit inside and decided floor-level was somehow appropriate). 

If you’re working in children’s bedrooms or playrooms, raise the board higher so young hands can’t reach live terminals during maintenance. Common sense, but it needs saying because people forget. 

And here’s one that trips people up constantly: if you’re relocating a board in a retrofit, always label the old tails route or remove it entirely. Future electricians will thank you for not leaving mystery cables buried in walls. 

Space Requirements: Don’t Cram It Into a Corner 

Regulation 513.1 requires adequate space for operation and maintenance. Here’s what that actually means in practice: 

• 600mm clearance in front of the cover. Not “sort of 600mm if you move the boxes.” Actual clear floor space so you can stand in front of the board, open the cover, and work on it without contorting yourself. 

• 150mm side clearance on the hinge side so the lid can swing open fully. Mount a board 50mm from a wall corner and you’ll spend the rest of the job kicking yourself every time you try to get access. 

• 150 lux lighting recommended so labels are readable. If the board’s in a dark cupboard under the stairs and you can’t see what you’re doing without a torch, that’s not adequate provision. 

BS 8300 adds that where a board is installed in a location used by disabled people, working space must allow for wheelchair access. That usually means more than 600mm clearance (closer to 800mm-900mm in practice). 

Environmental Considerations: Temperature, Damp, and UV 

Consumer units are rated for specific operating temperatures. The IET recommends keeping kit between -5°C and +35°C. Mount a board in a loft that hits 40°C in summer and you need to derate protective devices by 5% per 10°C rise above 30°C. That 32A MCB? It’s effectively a 28.8A MCB when it’s baking in a July heatwave. 

Damp porches, unheated garages, and outdoor locations all shorten component life. Minimum IP rating indoors is I P31 (protection against solid objects over 2.5mm and dripping water). If you’re mounting a board outdoors because there’s genuinely no other option, you need IP55 (dust protected and protected against water jets). 

Regulation 522.3 requires that wiring systems are selected and erected so no damage is caused by condensation or ingress of water during installation, use, or maintenance. That includes the cabling enclosure of the consumer unit. 

Direct sunlight degrades plastic tail guards and can cause overheating. If unavoidable, fit a drip shield over the door and consider a GRP enclosure rather than a standard plastic one. 

And here’s one that gets missed constantly: if you’re in a flood-risk area, mount the board above the anticipated flood line. Government guidance in “Preparing for Floods” specifically recommends this, and Regulation 522.3 makes it a requirement to protect against water ingress. 

Future-Proofing: Leave Spare Ways 

Leave at least 20% spare ways in domestic boards. One EV charger can take up three modules (40A Type A RCBO plus SPD plus whatever else you need depending on setup). A heat pump circuit? Another two or three modules. Solar PV with battery storage? You’re suddenly looking at a lot of board space. 

Route tails neatly. Use 25mm² singles, not twin-wall conduit, and allow a 50mm bending radius at the meter end to avoid stress on the meter terminals. Future electricians doing upgrades will appreciate boards where the tails are dressed properly and there’s room to work. 

Proximity to Sinks and Water 

General guidance from NHBC (the UK’s leading warranty and insurance provider for new homes) is to avoid positioning a consumer unit immediately above or alongside a sink. Where space exists, mount the board beyond the drainer. 

The rule of thumb is at least 300mm measured horizontally from the edge of any sink or wash basin opening to reduce the effects of splashing. Ideally, aim for 1000mm if you’ve got the space. 

Yes, I’ve seen boards mounted directly above kitchen sinks. No, it’s not compliant. No, “but there was nowhere else to put it” isn’t an excuse. Find another location. 

Special Situations That Need Part P Sign-Off 

All consumer unit relocations are notifiable work under Part P of the Building Regulations. That means a Part P registered electrician is required to carry out the work and issue a Building Regulations Compliance Certificate. Homeowners planning to DIY need to budget for Building Control fees if they’re not using a registered spark. 

Moving a Board More Than 3m from the Meter 

If you’re relocating a consumer unit more than 3 metres from the meter, you need to notify the Distribution Network Operator (DNO) because you’ll need new tails and potentially a new fuse. Don’t just extend the existing tails and hope no one notices. That’s how you end up with undersized cables or an illegal connection. 

Board Changes in Bathroom Annexes 

If you’re changing a board in a bathroom annex (weird layout, but it happens), you need to calculate zones properly and ensure all circuits have 30mA RCD protection. Bathrooms and electrical equipment don’t mix well, and BS 7671 Section 701 has specific requirements for locations containing a bath or shower. 

Flats with Communal Meter Rooms 

If you’re working in a flat with a communal meter room, fit a local service isolator inside the flat in addition to whatever’s in the meter cupboard. The resident needs to be able to isolate their own supply without accessing a shared space that might be locked or require building management access. 

Some DNOs require REC-sealed heads on consumer units in communal areas to prevent unauthorised access. Check local requirements before you start the job. 

Why This Matters for NVQ Portfolios 

Mis-placing a board is one of the most common snags on NVQ portfolios. Assessors will ask why you mounted it at that height, why you chose that location, what environmental factors you considered, and whether you’ve complied with Part M and BS 7671 accessibility requirements. 

If your answer is “because that’s where there was space” or “the customer wanted it there,” you’re going to struggle. The correct answer involves referencing regulations, explaining your thought process, and demonstrating that you’ve considered accessibility, environmental conditions, future expansion, and compliance with Building Regulations. 

Mounting height, free air around the lid, and weather protection sound mundane, but they’re the difference between a portfolio that passes first time and one that comes back with a list of corrections. 

Consumer unit location isn’t complicated. It just requires you to think beyond “where can I fit this?” and consider accessibility, environmental conditions, future needs, and regulatory compliance. 

Mount the main switch between 1350mm and 1450mm for new builds. Aim for around 1400mm in existing dwellings. Leave 600mm clearance in front, 150mm on the hinge side, and make sure there’s adequate lighting. Avoid damp, extreme temperatures, and direct sunlight. Stay at least 300mm away from sinks. Leave 20% spare ways for future circuits. And if you’re relocating a board, it’s notifiable work under Part P. 

Get it right and the board will serve the property for decades. Get it wrong and you’re creating problems for every electrician who comes after you, not to mention the homeowner who has to live with a board they can’t reach or a cupboard they can’t use because there’s a consumer unit in the way. 

Call us on 0330 822 5337. We’ll walk you through practical installation techniques, show you how to plan board locations that comply with Part M and BS 7671, and make sure your NVQ portfolio includes all the regulatory justifications assessors are looking for. No hype. Just proper training that prepares you for real-world jobs where location decisions matter.