If you have ever had electrical work carried out in a bathroom or wet room, you may have heard your electrician refer to it as a ‘special location’. It is a term used in the wiring regulations — BS 7671, and it has specific implications for how electrical installations in those areas must be designed and protected. Here is what it means and why it matters.

The Definition of a Special Location

In electrical terms, a special location is any area where the presence of water significantly increases the risk of electric shock. The most common example is a bathroom or shower room, but the definition also covers:

• Shower cubicles and wet rooms
• Swimming pools and their surrounding areas
• Saunas and steam rooms
• Hot tub installations
• Garden and outdoor water features

The reason these areas are treated differently is straightforward. Water lowers the body’s electrical resistance, which means that a level of voltage that would cause little harm in a dry environment can become dangerous — or even lethal — when the person is wet or in contact with water. This is why the regulations require additional protective measures in these spaces.

The Zone System

Bathrooms and shower rooms are divided into zones under the wiring regulations, based on their proximity to water sources. Each zone has different requirements for the type of electrical equipment that can be installed within it.

Zone 0 is inside the bath or shower tray itself — the area in direct contact with water. Only specially designed, very low-voltage equipment rated to at least IPX7 (waterproof) can be installed here, such as certain submersible lighting fixtures.

Zone 1 covers the area directly above the bath or shower tray, up to a height of 2.25 metres from the floor. Equipment in this zone must be rated to at least IPX4 (splash-proof). Fixed showers, certain shower pumps, and SELV (Safety Extra Low Voltage) lighting can be installed here.

Zone 2 extends 600mm beyond the perimeter of zone 1, and again up to 2.25 metres from the floor. The same IPX4 minimum rating applies. This zone is where shaver sockets — which must be a specific transformer-isolated type — are typically permitted.

Outside the zones, standard electrical fittings can be used, but RCD protection is still required throughout the room.

RCD Protection Is Mandatory

Regardless of zones, all circuits supplying electrical equipment in a bathroom or wet room must be protected by a Residual Current Device (RCD). An RCD monitors the flow of electricity through a circuit and cuts the power within milliseconds if it detects a fault — fast enough to prevent a fatal electric shock in most circumstances.

Modern consumer units typically have RCD protection built in, but older installations may not. If your home has an older fuse board, an EICR inspection will identify whether your bathroom circuits are properly protected.

What This Means in Practice

For homeowners and landlords, the practical implication is that any electrical work in a bathroom or wet room must be carried out by a qualified electrician who understands the zone requirements and the relevant regulations. This includes installing or moving light fittings, adding shaver sockets, installing extractor fans, or running circuits for heated towel rails and underfloor heating.

This type of work is notifiable under Part P of the Building Regulations, which means it must either be carried out by a registered competent person — such as a NICEIC-registered electrician — or submitted to the local authority for inspection. A registered electrician will self-certify the work and issue the relevant certificate on completion.

Need Electrical Work in Your Bathroom?

ATO Solutions carries out electrical installation and inspection work in bathrooms, wet rooms, and other special locations across South West London. All work is carried out to BS 7671 by NICEIC-accredited engineers and fully certificated on completion.

Talk to Us About Bathroom Electrical Work

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