Bathroom Electrical Zones: What Can Go Where?

Summary

Bathroom electrical zones exist because water and mains electricity are a lethal combination. BS 7671:2018+A2:2022 (the IET Wiring Regulations, 18th Edition) Section 701 defines the zones for any room containing a bath or shower, and specifies what equipment can be installed in each, what IP rating it needs, and how circuits must be protected. The zones are based on proximity to the water source -- the closer to the bath or shower, the stricter the requirements. Every electrician and plumber working in bathrooms needs to understand these zones because non-compliant installations are both dangerous and illegal under Part P of the Building Regulations. Getting it wrong can mean failed inspections, insurance issues, and serious risk to life.

Key Facts

• Four zones exist: Zone 0, Zone 1, Zone 2, and Outside Zones -- each with different IP rating and equipment requirements
• All bathroom circuits must have 30 mA RCD protection (Regulation 701.411.3.3) -- no exceptions
• Zone 0 requires minimum IPX7 (protection against temporary immersion) and only SELV up to 12V AC / 30V DC
• Zone 1 requires minimum IPX4 (splash-proof), or IPX5 where water jets are used for cleaning
• Zone 2 requires minimum IPX4 (splash-proof)
• Socket outlets are not permitted in Zones 0, 1, or 2 -- except shaver sockets to BS EN 61558-2-5 in Zone 2 or outside zones
• 13A socket outlets must be at least 3 m horizontally from the boundary of Zone 1
• Supplementary bonding can be omitted if all circuits have RCD protection and automatic disconnection is confirmed (Regulation 701.415.2)
• Electrical work in bathrooms is notifiable under Part P -- it must be done by a registered competent person or notified to Building Control

Zone Definitions

Zone 0

What it is: The interior of the bath tub or shower tray itself -- any volume that can hold water during normal use.

Dimensions: The space contained within the bath or shower basin, up to the rim or threshold.

IP rating required: Minimum IPX7 (protection against temporary immersion in water up to 1 m depth for 30 minutes).

What is allowed:

• Only fixed equipment specifically designed for use in this zone
• Must be SELV (Separated Extra-Low Voltage) at a maximum of 12V AC or 30V DC
• The SELV source (transformer) must be located outside Zones 0, 1, and 2
• Typical examples: whirlpool/jacuzzi pump units (sealed, manufacturer-rated for Zone 0), underwater bath lighting

What is NOT allowed:

• Any 230V equipment
• Switches of any kind
• Socket outlets

Zone 1

What it is: The volume directly above Zone 0 (above the bath or shower tray), extending upward to 2.25 m from finished floor level. For showers without a tray, Zone 1 extends 1.2 m from the centre point of the fixed shower head, measured horizontally.

Dimensions:

• Height: From the top of Zone 0 (rim of bath / top of shower tray) up to 2.25 m from the finished floor level, or the height of the highest fixed shower head/water outlet if greater than 2.25 m
• Width: The width of the bath or shower tray (for baths); 1.2 m radius from the shower head centre point (for showers without a tray)

IP rating required: Minimum IPX4 (protection against splashing water from all directions). Where water jets are used for cleaning purposes, minimum IPX5 (protection against low-pressure water jets).

What is allowed:

• SELV equipment (12V AC / 30V DC) with the transformer outside Zones 0, 1, and 2
• Fixed, permanently connected current-using equipment suitable for the zone, specifically:
  • Electric showers (must be RCD protected, correctly rated)
  • Whirlpool units
  • Electric instantaneous water heaters
  • Shower pumps
  • Ventilation/extractor fans (must be IPX4 minimum)
  • Towel rails / heating appliances (must be permanently connected, not plugged in)
  • Light fittings rated to at least IPX4

What is NOT allowed:

• Socket outlets (including shaver sockets)
• Switches (except those that form part of fixed current-using equipment, e.g. the on/off on an electric shower)
• Any equipment not designed for the zone or without adequate IP rating

Zone 2

What it is: The area extending 0.6 m horizontally beyond the boundary of Zone 1, and above the bath/shower up to 2.25 m from finished floor level. Also includes the area above Zone 1 up to the ceiling if the ceiling height exceeds 2.25 m (though some interpretations treat this as outside zones -- check with your scheme provider).

Dimensions:

• Horizontal extent: 0.6 m beyond the outer edge of Zone 1
• Height: Up to 2.25 m from finished floor level (same as Zone 1)
• Around a washbasin: Zone 2 extends 0.6 m from the edge of the basin

IP rating required: Minimum IPX4 (protection against splashing water from all directions). Where water jets are used for cleaning, minimum IPX5.

What is allowed:

• Everything permitted in Zone 1, plus:
  • Shaver supply units to BS EN 61558-2-5 (isolating transformer shaver sockets)
  • Luminaires, fans, heaters, and towel rails rated to at least IPX4
  • SELV equipment

What is NOT allowed:

• 13A socket outlets
• Standard switches (pull-cord switches are acceptable if the body of the switch is outside Zone 2)

Outside Zones

What it is: Any area in the bathroom beyond Zone 2 -- more than 0.6 m from the Zone 1 boundary and/or above 2.25 m from finished floor level.

What is permitted:

• Standard equipment can be installed, but all circuits must still have 30 mA RCD protection because the room contains a bath or shower
• 13A socket outlets are permitted only if they are at least 3 m horizontally from the boundary of Zone 1
• Shaver supply units to BS EN 61558-2-5
• Standard switches, light fittings, and other accessories
• No specific IP rating required by BS 7671 (though common sense dictates moisture-resistant fittings in any bathroom)

Practical note: In most UK bathrooms (typically 2-3 m wide), there is very little or no space that qualifies as "outside zones." This effectively means no 13A sockets in the vast majority of bathrooms.

Equipment Guide

Key for the table:

• "Yes" means permitted with the stated conditions
• "No" means not permitted
• All equipment in all zones must be on a 30 mA RCD-protected circuit
• "Permanently connected" means hardwired by an electrician, not plugged into a socket

Detailed Guidance

Where can I install a light in a bathroom?

Lights can be installed in Zones 1 and 2 provided they carry a minimum IP rating of IPX4. In Zone 0, only SELV 12V fittings rated to IPX7 are permitted -- this is rare and mainly applies to underwater feature lighting in baths.

For recessed downlights in a ceiling above Zone 1, pay attention to the back of the fitting as well. If the void above the ceiling is within Zone 1 (i.e. the ceiling is below 2.25 m), the rear of the fitting also needs appropriate protection. Many IP65-rated downlights are designed for this purpose -- IPX4 on the face, fully sealed at the rear.

Pull-cord light switches are the standard solution in bathrooms. The switch mechanism itself must be located outside the zones, but the pull cord can hang down into zoned areas.

Can I install a shaver socket in a bathroom?

Yes, but only in Zone 2 or outside zones, and it must be a dedicated shaver supply unit complying with BS EN 61558-2-5. These units contain an isolating transformer that limits the risk of electric shock. They are not the same as a standard 13A socket -- a standard socket is never permitted in Zones 0, 1, or 2.

Shaver sockets are typically mounted near the mirror/basin area. Since the basin area is usually Zone 2 (0.6 m from the basin edge), placement next to or above the mirror is normally compliant.

Where can I install an extractor fan?

Extractor fans are commonly installed in Zone 1 (directly above the shower) or Zone 2. The fan must be rated to at least IPX4 in either zone. If water jets are used for cleaning in the area, IPX5 is required.

The fan must be permanently connected (hardwired), not plugged in. The isolating switch for the fan should be located outside the bathroom or be a pull-cord type with the switch body outside the zones. If the fan is on the lighting circuit (which is common), it still needs its own means of isolation.

In practice, many bathroom extractor fans are rated IP44 or IP45, which covers Zones 1 and 2 respectively.

Do I still need supplementary bonding?

Under BS 7671 Regulation 701.415.2, supplementary bonding can be omitted in a bathroom provided all three of the following conditions are met:

1. All final circuits of the location comply with the requirements for automatic disconnection of supply (Regulation 411.3.2)
2. All final circuits of the location have additional protection by means of a 30 mA RCD
3. All extraneous-conductive-parts of the location are effectively connected to the main protective equipotential bonding (Regulation 411.3.1.2)

In practice, in a modern installation with a consumer unit fitted with RCBOs or RCDs protecting all bathroom circuits, and where main bonding is confirmed to gas, water, and other services, supplementary bonding is not required.

However, if you cannot confirm all three conditions -- for example, in an older property where the consumer unit lacks RCD protection on the bathroom circuit, or where main bonding is absent or suspect -- supplementary bonding must be installed. This means connecting all extraneous-conductive-parts (exposed metallic pipework, radiators, baths, etc.) together with 4 mm2 earth cable.

Practical advice: Always test and verify. If you are adding a new bathroom circuit, fit RCD protection and confirm main bonding, which removes the need for supplementary bonding. If you are working on an existing installation and cannot verify the conditions, install supplementary bonding -- it is cheap insurance.

Frequently Asked Questions

Can I have a socket outlet in a bathroom?

A 13A socket outlet is only permitted if it is outside all zones and at least 3 m horizontally from the Zone 1 boundary. In the vast majority of UK bathrooms, this is physically impossible due to room size. The exception is shaver supply units (to BS EN 61558-2-5), which are permitted in Zone 2 and outside zones. If you need to charge electric toothbrushes or shavers, a shaver socket with a built-in USB outlet is the compliant solution.

Does a cloakroom / WC without a bath or shower need zoning?

No. Section 701 only applies to rooms containing a bath or shower. A WC with just a toilet and basin does not require zoning, and standard socket outlets and switches can be installed. However, if the room later has a shower added, the zoning requirements will then apply retrospectively to all existing equipment.

What about wet rooms?

Wet rooms follow the same zone definitions, but because there is no shower tray, the zone measurements are taken from the fixed shower head. Zone 1 extends 1.2 m horizontally from the centre of the shower head. The floor of the entire wet room is effectively Zone 0 or Zone 1 depending on design, which has implications for underfloor heating installations.

Do these rules apply to en-suites and hotel bathrooms?

Yes. Section 701 applies to all locations containing a bath or shower in domestic, commercial, and hospitality settings. En-suites, hotel bathrooms, gym showers, and care home wet rooms all follow the same zoning rules.

Who can do electrical work in a bathroom?

Under Part P of the Building Regulations (England and Wales), electrical work in a room containing a bath or shower is notifiable work if it involves a new circuit or alteration to an existing circuit within the zones. This means it must be either:

• Carried out by an electrician registered with a competent person scheme (NICEIC, NAPIT, ELECSA, etc.) who can self-certify, or
• Notified to the local authority Building Control department before work starts

A like-for-like replacement of a fitting (e.g. swapping one IPX4 light for another) is generally not notifiable, but adding a new circuit for a shower or moving a fan to a different zone is.

Regulations & Standards

• BS 7671:2018+A2:2022 -- Requirements for Electrical Installations (IET Wiring Regulations, 18th Edition), Section 701: Locations Containing a Bath or Shower

• Building Regulations Approved Document P -- Electrical Safety in Dwellings (England and Wales)

• BS EN 61558-2-5 -- Safety of transformers, reactors, power supply units and combinations thereof. Particular requirements for shaver transformers and shaver supply units

• BS EN 60529 (IEC 60529) -- Degrees of protection provided by enclosures (IP Code)

• BS EN 12464-1 -- Light and lighting (relevant to bathroom lighting design)

• IET BS 7671 Section 701 (PDF)

• IET Part P Guidance

• GOV.UK Approved Document P

• NICEIC Zonal Requirements Technical Guide (PDF)

• Bathroom Electrical Zones BS 7671 Guide -- Elec-Mate

• ProCerts -- Bathroom Zones 18th Edition

• IET EngX Forum -- Supplementary Bonding Discussion

• SELECT Electrical -- Bathroom Installations Guide (PDF)

• cable sizing -- Electrical cable sizing guide

• part p notifications -- When Part P notification is needed

• bathroom refit -- Full bathroom renovation scope