Socket, Switch and Consumer Unit Heights: Recommended Positions and Part M Requirements

Quick Answer: Approved Document M of the Building Regulations sets the standard mounting band for new dwellings: switches and sockets between 450 mm and 1,200 mm above finished floor level (AFFL), with consumer units mounted between 1,350 mm and 1,450 mm to the top of the enclosure. These figures apply to new build and material alterations; replacement-on-like-for-like work is not retrospectively bound. BS 7671 has no socket-height regulation but defers to Part M for accessibility.

Summary

The numbers in Approved Document M Volume 1 (dwellings) are the figures every domestic electrician should know by heart. They are not "recommended best practice" — they are the deemed-to-satisfy heights for new dwellings, and a Part P or Building Control inspector will check them on a sample basis. The intent is straightforward: people with limited reach or who use a wheelchair can operate switches and sockets without specialist adaptation, and someone resetting an MCB does not need to climb on a chair. The same logic underlies the Part M figures for kitchens (worktop sockets) and bathrooms (light switch positions).

Outside new build the picture is different. There is no legal duty to retrospectively raise sockets in a 1970s house just because they sit at 250 mm AFFL. But once a job becomes a material alteration — a kitchen refit, a rewire, a structural extension — Part M applies to the parts of the building affected by the work, and those new circuits must meet the band.

For owners and homeowners reading this, the practical question is usually about kitchens, where worktop heights, splashback tile bands, and integrated appliance positions all interact with electrical positions. Get the heights wrong and either the electrician has to come back and re-chase a wall after the kitchen fitter has installed it, or the customer ends up with a socket dropped behind the dishwasher that nobody can reach to isolate.

Key Facts

Quick Reference Table

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Accessory Height to centreline (or top) AFFL Source
13 A socket — habitable room (no obstruction) 450 mm Part M / industry standard
13 A socket — kitchen worktop band 100–150 mm above worktop Part M (within 450–1,200 mm band)
13 A socket — appliance behind unit (FCU isolator above) 450 mm to socket; 1,200 mm to FCU Part M
Light switch 900–1,200 mm Part M
Wall-mounted thermostat 1,200–1,500 mm Industry; manufacturer guidance
Cooker switch (45 A double pole) 1,400–1,500 mm or 150 mm above worktop Manufacturer / installer choice
Shaver socket (bathroom) 1,200–1,400 mm Industry; outside zones
Bathroom pull cord (light) Ceiling Standard
Outdoor weatherproof socket 600–1,200 mm Part M; IP rating mandatory
Door bell push / intercom 900–1,200 mm Part M
Consumer unit (top of enclosure) 1,350–1,450 mm Part M
EV charger (centreline of socket) 750 mm typical (max 1,200 mm) BS 7671 Section 722 / OZEV guidance
Smoke alarm (ceiling) 300 mm min from wall BS 5839-6

Detailed Guidance

Where Part M applies (and where it does not)

Approved Document M Volume 1 sets the requirements for dwellings. Volume 2 covers buildings other than dwellings and adds public-building duties (signage, induction loops, automatic doors). For domestic electricians, Volume 1 is the relevant document.

The trigger conditions for Part M to apply are:

Routine maintenance, like-for-like replacement, decorative upgrades, and the addition of one or two new sockets to a circuit in an existing dwelling are not material alterations. There is no retrospective compliance duty for older houses.

In practice, the most common compliance pinch-points are:

The 450 mm rule — why it exists

The 450 mm minimum is a wheelchair-reach figure. From a standard manual wheelchair, a person can reach down to approximately 400–450 mm AFFL without leaning forward in a way that risks losing balance. The 1,200 mm upper limit is a high-reach figure for the same population. The combined band — 450 to 1,200 mm — defines the "comfortable operating range" for a fully accessible dwelling.

The kitchen exception (sockets above worktop) sits within this band by definition, since worktops are typically 900 mm AFFL and the 100–150 mm above worktop placement puts sockets at 1,000–1,050 mm — well inside the 450–1,200 mm range.

Consumer unit positioning

The 1,350–1,450 mm to-top rule for consumer units is one of the more frequently misunderstood Part M figures. Common errors:

A consumer unit on the underside of a stair (a common location in 1970s and 1980s houses) is acceptable provided the to-top height respects 1,350–1,450 mm and there is unobstructed access space in front of the unit — generally 1,000 mm clear width and 1,200 mm depth for wheelchair turning.

Kitchens — where heights matter most

Kitchens drive most of the height-position questions because of the interaction between:

A workable kitchen layout typically uses:

If the cabinet design uses tall units with no clear wall behind worktop (e.g. a galley kitchen with a window between two tall units), the 450 mm band has to be hit on a non-worktop wall. Plan this with the kitchen fitter at first-fix.

Bathrooms — zones override Part M heights

Inside bathroom zones 0, 1 and 2 (defined by BS 7671 Section 701), wall-mounted switches are not permitted regardless of height. Pull-cord ceiling switches replace wall switches. Outside the zones, normal Part M heights apply. A shaver socket fitted to BS EN 61558-2-5 inside the bathroom is the only socket type permitted in zone 2 and at standard reach height (1,200 mm AFFL or thereabouts).

EV chargers — newer rules

For dedicated EV charging points, BS 7671 Section 722 and OZEV guidance recommend a centreline height of 750 mm for the connector, with the maximum at 1,200 mm. The lower figure recognises that the connector cable hangs and is gripped by the user — too high a fixing puts strain on the cable and connector lock. Mount the upstream isolator and SPD/RCBO inside the dwelling at standard heights; the external charger sits at the lower position.

Consumer-facing question — "the electrician has put the sockets really low — is that right?"

In a new build or post-rewire dwelling, sockets at 450 mm AFFL are correct and required. They feel low compared to older 1980s houses where 250 mm was common, but the change reflects accessibility duties under Part M. Sockets at 250 mm AFFL are specifically out of compliance for new build because they sit below the 450 mm wheelchair-reach lower limit.

Frequently Asked Questions

Do I have to comply with Part M when I add one socket to a bedroom?

No, a single socket addition is not a material alteration and does not trigger Part M. Best practice is still to mount the new socket at the same height as adjacent existing sockets so the room is consistent.

Can I keep the consumer unit at 1,800 mm AFFL on a CU swap?

If the work is a notifiable consumer unit replacement, Part M applies to the new CU. Mounting it back at 1,800 mm is a Part M non-compliance. Record any departure on the EIC and explain to the homeowner that they have the option of either accepting the non-compliance (declared) or moving the CU.

What height for an outdoor garden socket?

Inside the 450–1,200 mm Part M band; usually 600 mm AFFL for a garden patio socket, mounted in an IP56 weatherproof enclosure with RCD protection (per BS 7671 Section 522 and 411).

Do switches all have to be at the same height in a room?

Best practice is to align switches in the same plane (same height across one wall) for visual consistency. Part M only sets the band, not consistency.

What about under-stair cupboards? Is a CU in a cupboard acceptable?

Yes, provided the cupboard door allows clear access, the to-top height of the CU is 1,350–1,450 mm AFFL, and the cupboard contents do not obstruct access. Avoid mounting a CU in a wardrobe with hanging space below.

Regulations & Standards