Water and electricity don’t mix, which is why bathrooms are the one room in a UK home where electrical installations are governed by a specific set of rules. These rules divide the room into zones based on how close a fixture is to a bath, shower or sink, and each zone dictates what can be fitted and how well protected it needs to be. Get it wrong and you’re looking at a safety risk, a failed EICR, or both.
Here’s a plain breakdown of what the bathroom zones actually mean and what you can and can’t put in each one.
What are the bathroom electrical zones?
The IET Wiring Regulations (BS 7671) split bathrooms into three zones:
Zone 0 is inside the bath or shower itself. Anything fitted here must be low voltage and rated at least IPX7, meaning it can survive being fully submerged.
Zone 1 covers the area directly above the bath or shower, up to 2.25m from the floor. Fittings here need to be at least IPX4 (splashproof), or IPX5 if the room is likely to be hosed down, such as in a commercial setting.
Zone 2 extends 0.6m out from the edge of the bath or shower, and also covers the area around a basin within 0.6m horizontally. Fittings here still need to be IPX4 rated in most cases.
Everything outside these zones is generally treated as a standard room, though sockets still need to be positioned at least 3m from the edge of a bath or shower unless they’re shaver sockets or RCD protected.
What can go in each zone
In practice, this is what most homeowners want to know:
Lighting in Zone 1 needs to be low voltage, fully enclosed and rated IPX4 or higher. Standard pendant fittings and open downlights are not suitable here. In Zone 2, requirements ease slightly but IPX4 is still the safe standard.
Sockets are not permitted in Zones 0, 1 or 2 at all, other than shaver sockets designed to that specification. Any general socket needs to be outside these zones and at least 3m from the edge of the bath or shower unless it’s protected by a 30mA RCD.
Extractor fans are usually fine in Zone 1 as long as they’re rated for the location, which most bathroom-specific models are.
Heated towel rails and underfloor heating need to be checked against zone requirements too, particularly if they’re wired rather than plumbed.
Do I need an electrician for bathroom electrics?
Bathroom electrical work falls under Part P of the Building Regulations and is notifiable work in almost all cases, because of the added risk from water. This is one area where DIY isn’t worth the risk, even for jobs that might seem straightforward elsewhere in the house. Our guide on what electrical work you can do yourself covers this distinction in more detail.
A registered electrician will know the zone requirements without needing to look them up, will use fittings rated for the right IP class, and will certify the work so it’s on record if you come to sell the property or need an EICR carried out.
Common mistakes we see
The most frequent issue we come across on bathroom rewires and renovations is downlights fitted in Zone 1 that aren’t properly rated, usually left over from a previous renovation that didn’t account for the zones. The second most common is a socket positioned too close to a basin, often added years after the original install without anyone checking the distance.
If your bathroom hasn’t had any electrical work done in a while, or you’re not sure what’s already installed, it’s worth having it checked as part of a wider EICR inspection. It’s also worth reading up on why an RCD might keep tripping, since bathroom circuits are one of the more common causes when a fault develops.
Planning a bathroom renovation?
If you’re renovating and want the electrics done properly from the start, get a registered electrician involved before the tiling goes in. Moving a light or adding a shaver socket is far easier to plan for at the design stage than to retrofit once the room is finished. We work across Bristol and South Gloucestershire and can advise on layout as well as carry out the installation and certification.
