Bathroom Zones 0, 1, 2 and IP Ratings: BS 7671 Section 701

Summary

Bathroom zoning is the most commonly-tested topic in domestic electrical inspections and the source of frequent rework on bathroom refurbishments. Section 701 of BS 7671 sets the rules, and they apply to every domestic bathroom in England, Wales, Scotland and Northern Ireland — there are no regional variations.

For electricians, the zone system answers two questions on every bathroom job:

1. Can I put a fitting (light, fan, socket, accessory) here?
2. What IP rating must the fitting be?

For non-specialists, the rules sound simple but the details catch people out — corner showers, baths with no enclosure, walk-in wet rooms, and accessible designs all require careful zone calculation. The Wiring Regulations have evolved (Zone 3 was removed in BS 7671:2008 and the rules around 230V sockets relaxed in BS 7671:2018), so older guidance can be misleading.

The single most common failure on EICR (Electrical Installation Condition Report) is unprotected (no RCD) bathroom circuits in older properties. Section 701.411.3.3 requires 30mA RCD on every bathroom circuit, full stop.

Key Facts

• BS 7671:2018+A2:2022 — current Wiring Regulations. Section 701 governs bathrooms.
• Zones replaced "areas" — pre-2008 regulations used the term "areas"; current rules use "zones".
• Zone 0 — inside the bath or shower basin. IPX7 (immersion-rated). 12V SELV only.
• Zone 1 — above the bath/shower, up to 2.25m from the floor. IPX4. SELV/low-voltage rules apply.
• Zone 2 — 0.6m horizontally from Zone 1, and 2.25m vertically. IPX4.
• No Zone 3 — Zone 3 was deleted in BS 7671:2008. The area beyond Zone 2 is unzoned (but still in the bathroom).
• Bathroom socket rule — 230V sockets allowed in unzoned area beyond Zone 2, provided they are at least 3m horizontal from Zone 1. RCD protection mandatory.
• Shaver socket — only socket type permitted in Zone 2; must be BS EN 61558-2-5 (isolated transformer). Unlimited location.
• 30mA RCD — required on every circuit in the bathroom (not just sockets). Lights, fan, towel rail, shower all included.
• Supplementary equipotential bonding — was required (Regulation 701.415.2). Now allowed to be omitted IF the bathroom has main equipotential bonding AND all circuits have 30mA RCD protection AND all extraneous-conductive-parts are connected to the main earth.
• IP ratings — first digit (solid object ingress 0-6, X = not specified), second digit (water ingress 0-8).
• IPX4 — splash-proof from any direction.
• IPX5 — water jets from any direction.
• IPX7 — temporary immersion (up to 30 mins, depth 1m).
• IPX8 — continuous immersion.
• Class II equipment — double-insulated; preferred for Zone 1 and Zone 2 fittings.
• Class III equipment — SELV (Separated Extra Low Voltage). Required in Zone 0.

Quick Reference Table — Zone Definitions

Quick Reference Table — Common Fittings and Permitted Zones

Detailed Guidance

Defining the zones — section view

SECTION — BATH WITH OVERHEAD SHOWER
====================================

         ┌─────────────────┐
         │                 │
   2.25m │     ZONE 1      │   ← Above bath: IPX4
         │                 │
         │  ┌──┐           │
         └──┤  ├───────────┘  Above showerhead
            │  │   Bath        if fixed shower
            │  │  rim           
       ─────┼──┼─────────       (Zone 1 extends to
        ▲   │  │       ▲        showerhead height
        │   │  │       │         if higher than 2.25m)
        │   │  │       │
   Zone 0 (inside bath, IPX7 if submersible)
        │   │  │       │
   ─────┼──┼──┼──┼──┼───── floor
            <───>  
            0.6m horizontal from bath edge = ZONE 2
                  (Zone 2 also extends 2.25m vertical)

Defining zones for shower enclosures

PLAN — SHOWER ENCLOSURE
=======================

       Wall
   ─────────────────
       │ ZONE 0  │
       │ (shower │ ← inside enclosure, IPX7
       │ basin)  │
       │         │
       ─────┬────┴───── shower door/screen
       │    │
       │    │
       │ ZONE 1   ← around enclosure walls
       │ + Zone 2 ← extends 0.6m horizontal
       │
   ─────┴──────────
       0.6m

For walk-in showers (no tray, just a drain), Zone 0 is the entire shower area to a height of 100mm above floor; Zone 1 is the rest of the shower area up to 2.25m; Zone 2 extends 0.6m around the entire shower area.

The supplementary equipotential bonding question

Pre-2008, all bathrooms required supplementary equipotential bonding — a 4mm² earth conductor connecting all extraneous metalwork (pipes, towel rail, taps) to a local earth bar.

Current rules (BS 7671:2018+A2:2022, Regulation 701.415.2): supplementary bonding can be omitted if:

1. The main protective bonding is in place (gas and water meters bonded to MET).
2. All circuits in the bathroom have 30mA RCD protection.
3. All extraneous-conductive-parts (pipes) are connected to the main earth via the main protective bonding.

For a typical modern installation with plastic supply pipes and a fully-RCD-protected consumer unit, supplementary bonding is not required. For older installations with copper supply pipes and split-load CUs, supplementary bonding may be retained as belt-and-braces.

RCD protection — universal

Section 701.411.3.3 requires 30mA RCD on every circuit in a bathroom:

• Lighting circuit
• Bathroom fan
• Electric shower
• Heated towel rail
• Shaver socket
• Any other bathroom-located fitting

For a modern consumer unit with RCBOs on every circuit, this is automatic. For an old split-load consumer unit, only RCD-protected circuits can serve the bathroom — RCBO upgrade or full board replacement is required.

Inspection and testing

An EICR on a bathroom should record:

Common bathroom installation faults

• Light switch inside bathroom — wall-mounted switches are NOT permitted in Zone 1 or 2. Use a pull-cord (Class II) or switch outside the bathroom.
• 230V socket in bathroom for hairdryer — only permitted ≥3m from Zone 1, which is impossible in most bathrooms under 6m². Use a shaver socket or external socket on the landing.
• Pendant light over bath — only permitted if rated IPX4 and Class II, and within 2.25m height limit. Most pendant lights fail IP rating.
• Standard wall fan in Zone 1 — bathroom fans must be IPX4 minimum. Standard kitchen fans don't qualify.
• Towel rail with timer plug — towel rails must be hard-wired through a fused spur with 30mA RCD, not a plug.

Wet room and walk-in shower considerations

For wet rooms (no defined shower enclosure, the whole floor is the shower):

• Zone 0 = the entire wet room floor area to 100mm
• Zone 1 = entire wet room volume up to 2.25m
• Zone 2 = effectively the rest of the bathroom

In practice, this means a wet room is treated as one large Zone 1, with all fittings IPX4 and 30mA RCD. Floor heating in a wet room must be SELV (typically a 12V mat) or specifically rated for wet room use.

Frequently Asked Questions

Can I put a socket in the bathroom for a washing machine or tumble dryer?

Only if it's at least 3 metres horizontally from Zone 1 (the bath or shower zone), and protected by a 30mA RCD. In practice this rules out almost all UK domestic bathrooms — the laundry needs to be in a separate utility room or a corner where 3m clearance can be measured. The exception is a shaver socket, which is allowed in Zone 2 if it meets BS EN 61558-2-5 (isolated transformer).

Do I need supplementary bonding in a modern bathroom?

Not if the three conditions of 701.415.2 are met: main protective bonding present, all circuits RCD-protected, extraneous-conductive-parts connected to main earth via main bonding. Most modern installations meet these — a fully-RCBO'd consumer unit and a metal water supply pipe bonded at the meter location.

For older installations (split-load CUs with only one RCD bank), or where any condition is in doubt, retain supplementary bonding.

What IP rating do I need for a bathroom downlight?

Zone 1 (above bath or shower, up to 2.25m): IPX4 minimum, Class II preferred. Zone 2: IPX4 minimum. Outside Zone 2: no IP minimum, but IPX4 still recommended near sinks. SELV (12V) fittings are always permitted in Zone 0 but require an external driver in an unzoned area.

How is Zone 1 measured for a freestanding bath?

Zone 1 wraps around the entire bath, vertical from the rim of the bath upward to 2.25m. Zone 2 extends 0.6m horizontal from the bath edge in all directions, vertical to 2.25m. For a freestanding bath in the middle of a room, this can include the entire central floor area as Zone 2 — restricting where wall-mounted socket and switch positions can be.

What about an electric shower?

Electric showers must be designed and rated for installation in Zone 1 (which is where they always sit). They are hard-wired from a dedicated 30A or 40A circuit with double-pole isolator outside the bathroom and 30mA RCD protection. Modern showers are IPX5 minimum. Always follow the manufacturer's data plate for cable size, circuit rating and IP zone certification.

Regulations & Standards

• BS 7671:2018+A2:2022 — Requirements for Electrical Installations (IET Wiring Regulations). Section 701 governs bathrooms.

• Building Regulations Approved Document Part P — Electrical safety in dwellings. Bathroom electrical work is notifiable.

• BS EN 60529:1992 — Degrees of protection provided by enclosures (IP code).

• BS EN 61558-2-5:2010 — Safety of transformers, reactors, power supply units. Shaver sockets.

• Electricity Safety, Quality and Continuity Regulations 2002 — supply-side safety, relevant to earthing/bonding.

• IET On-Site Guide (current edition) — practical guidance accompanying BS 7671.

• NICEIC / NAPIT Guidance Notes — Competent Persons Scheme guidance.

• IET — BS 7671:2018+A2:2022 (Wiring Regulations) — primary standard

• Approved Document P — Electrical safety (gov.uk) — Part P

• IET — On-Site Guide — practical companion to BS 7671

• NICEIC — Bathroom installation guidance — CPS guidance

• Electrical Safety First — bathroom safety — consumer-facing reference

• safe isolation procedure — safe working before bathroom alteration

• earthing and bonding — main vs supplementary bonding

• wet room construction — wet room electrical considerations

• electrical installation condition report — EICR for bathrooms