Bathroom and Kitchen Electrical: What the Rules Actually Require

Bathrooms are divided into zones, and how close something is to water decides what is allowed there. That one rule shapes most of what is and is not possible in a bathroom fit-out, and it is the reason your electrician sometimes says no to where you wanted the switch.

Kitchens have a different problem. Not zones so much as capacity: modern appliances want more dedicated circuits than older houses were built with, and that usually turns into a switchboard conversation.

Here is what actually matters in both rooms, and the sequencing mistake that costs coast homeowners the most money.

Bathroom zones, in plain terms

The idea is simple. The closer a position is to the bath, shower or basin, the more protected any fitting there has to be, and some things are not permitted at all. Inside the shower is the strictest. Directly above and around it is next. The further out you go, the more ordinary the rules become.

I am not going to reproduce the standard here as advice, because the detail matters and it is our job to apply it. What is worth knowing as a homeowner is that this is why a light fitting that looks fine in a catalogue cannot always go where you want it, and why the switch is often outside the door.

Extractor fans: the one that actually matters

A bathroom fan is not optional in any practical sense. Coast bathrooms without decent extraction get mould, and mould is a moisture problem, not a cleaning problem.

The thing people get wrong is where the fan vents to. A fan that simply pushes air into the ceiling space has not removed the moisture from the house, it has moved it somewhere you cannot see, into the insulation and the framing. It has to be ducted to outside.

• Ducted properly to an external vent, not just into the roof cavity
• Sized for the room rather than whatever was on the shelf
• Run on a timer or a humidity sensor, so it keeps going after the shower stops, which is when most of the moisture is still in the air
• Positioned to actually pull air across the shower, not tucked in a far corner

If you already have a fan and the bathroom still steams up and stays damp, the ducting is the first thing worth checking.

Heated towel rails and underfloor heating

Both are common in coast renovations and both need thinking about at the wiring stage rather than afterwards.

A towel rail wants its own switched supply in a permitted position, and the switch usually sits outside the wet zone. Underfloor heating goes in under the tiles, so it has to be planned before the tiler starts, and it needs its own protection at the board. Deciding you want it once the floor is down means lifting the floor.

How many circuits a modern kitchen needs

More than most older houses have. A kitchen built in the 1970s was not designed for an induction cooktop, a wall oven, a dishwasher, a microwave and a coffee machine all going at once.

• Ovens and cooktops generally want their own dedicated circuits, and induction in particular draws hard
• Dishwasher and waste disposal are usually separate again
• Bench power points need to be planned around where you will actually work, not spaced evenly for the sake of it. People consistently under-order these and regret it
• Rangehood needs a supply and, like the bathroom fan, wants to vent outside rather than recirculate if the layout allows

Add those up and an older switchboard often has nowhere left to put them. That is not a problem with your kitchen plan, it is just the next job, and it is much better discovered at design stage than the week the appliances land.

The sequencing mistake that costs the most

Getting the electrician in too late.

The least expensive time to do any of this is when the walls and floor are open, before the linings, tiling and cabinetry. Cable runs where it needs to, everything lands where you want it, and nobody is cutting into a finished surface.

Once the room is tiled and the cabinets are in, moving a power point 400mm can mean a tiler, a plasterer and a painter as well as an electrician. That is how a small change turns into a large invoice.

So the order that works: layout decided, electrician walks it with you before linings go on, first fix, then the rest of the trades, then fit-off at the end.

This is prescribed work

Kitchen and bathroom electrical is prescribed electrical work. It has to be done by a registered electrician and certified, and you should get the paperwork on completion. That is what your insurer will want if anything ever happens, and what a buyer's lawyer will ask about later.

Talk to us before the linings go on

If a kitchen or bathroom is on the cards, get us in at planning rather than at fit-off. It costs nothing to walk it and it is the single easiest way to avoid paying twice. Call 0274 466 737 or get a free quote. More on what we do in kitchens and bathrooms.