BS 7671 Guide · Section 7
Special locations (Part 7)
Some places raise the shock or fire risk well above a normal room: wet skin, bare feet, livestock, temporary wiring or the public within reach. Part 7 adds extra rules for these locations on top of Parts 1 to 6. It doesn’t replace them.
How Part 7 works
Each Part 7 section tightens, adds to or switches off general rules for one location. The digits after 7xx match the general regulation being changed: 701.411.3.3 modifies 411.3.3, but only in rooms with a bath or shower.
Many sections use zones. The closer to water, or the more likely someone is wet and touching earth, the stricter the rules on equipment, IP rating and voltage.
Summary: what each location adds
A quick reminder of the headline extras, not a design check.
Water and heat
| Section | Location | Key extra requirements |
|---|---|---|
| 701 | Bath and shower rooms | Zones 0, 1 and 2. 30 mA RCD on all circuits. Sockets at least 2.5 m from zone 1. Supplementary bonding unless three conditions are met. |
| 702 | Swimming pools, basins, fountains; outdoor hot tubs and religious pools (new in A4) | Zone 0 is the water. Zone 1 runs 2 m out from the rim and 2.5 m up. Zone 2 runs a further 1.5 m. SELV at 12 V AC / 30 V ripple-free DC in zone 0. IPX8 in zone 0. Supplementary bonding of extraneous-conductive-parts in all zones. |
| 703 | Saunas | Temperature zones inside the cabin. At least IPX4 (IPX5 if hosed down). Switchgear outside the cabin unless built into the heater. 30 mA RCD on the sauna circuits; check the heater maker’s instructions. |
| 753 | Floor and ceiling heating | 30 mA RCD. Heating zone limited to 80 °C. IPX7 for units cast into concrete. In bathrooms, a metal sheath or grid connected to the CPC unless SELV. |
Sites, outdoors and temporary
| Section | Location | Key extra requirements |
|---|---|---|
| 704 | Construction and demolition sites | Sockets up to 32 A on RLV, SELV, electrical separation or a 30 mA RCD. Circuits with sockets over 32 A on an RCD of 500 mA or less. PME earthing restricted. |
| 705 | Agricultural and horticultural | 30 mA RCD for sockets up to 32 A, 100 mA above 32 A, 300 mA for other circuits. Supplementary bonding including the floor grid in livestock areas. At least IP44. |
| 708 / 721 | Caravan parks and caravans | BS EN 60309-2 pitch sockets, at least 16 A and IP44. Each socket on its own overcurrent device and 30 mA RCD that breaks the neutral. No PME earth to caravan metalwork. 30 mA RCD inside the caravan. |
| 709 | Marinas | Each socket individually protected, including a 30 mA RCD. No PME earth to the boat. A4: isolating transformers to BS EN 61558-2-4 to stop galvanic currents. |
| 711 | Exhibitions, shows, stands | 30 mA RCD on sockets up to 32 A. Temporary supply cables protected at origin by an RCD of 300 mA or less. Inspect after every build on site. |
| 714 | Outdoor lighting, highway supplies, street furniture | A4 clarifies the scope. Publicly accessible lighting needs 30 mA RCD protection unless SELV. |
Systems and specialist installations
| Section | Installation | Key extra requirements |
|---|---|---|
| 710 | Medical locations | Fully redrafted in A4. Specialist design. See the notes below. |
| 712 | Solar PV | Covered in Section 8. |
| 715 | ELV lighting | SELV source. High currents at low voltage, so fire risk and voltage drop drive the design. |
| 716 | Power over Ethernet (new in A4) | Standards-compliant PSE or a SELV-type source. No more than 750 mA design current per conductor. Balanced ICT (data) cabling. |
| 722 | EV charging | Covered in Section 8. |
Regulation references: Part 7 Sections 701 to 753; 411.3.3; 415.1.1; 415.2
Bathrooms and shower rooms (701)
Wet skin lowers body resistance, and taps and pipes give a good path to earth.
The zones
- Zone 0 is the inside of the bath or shower tray. Only fixed equipment made for the job, rated at least IPX7, on SELV of no more than 12 V AC or 30 V ripple-free DC. The safety source must sit outside the zones.
- Zone 1 is directly above the bath or tray, up to 2.25 m above finished floor level or the height of the highest fixed shower head, whichever is higher. For a walk-in shower without a tray, it extends 1.2 m from the centre of the fixed water outlet. Only fixed equipment suitable for the zone, such as an electric shower, extractor fan or suitable luminaire, at IPX4 or better.
- Zone 2 extends 0.6 m horizontally beyond zone 1, to the same height. IPX4 minimum.
Use IPX5 in zones 1 and 2 where water jets are used for cleaning, such as gym showers.
RCDs, sockets and shavers
All low voltage circuits serving the room need 30 mA RCD protection, as do circuits that only pass through zones 1 or 2.
230 V socket-outlets must be at least 2.5 m horizontally from the zone 1 boundary. The exception is a shaver supply unit to BS EN 61558-2-5, which can go in zone 2 if direct spray is unlikely.
Supplementary bonding
Local supplementary bonding can be left out only when all three conditions are met:
- every final circuit in the room meets the disconnection times for automatic disconnection of supply;
- every final circuit in the room has 30 mA RCD protection; and
- all extraneous-conductive-parts in the room are effectively connected to the main protective bonding.
Regulation references: 701.411.3.3, 701.415.2, 701.512.2, 701.512.3
Outdoor hot tubs (702, new scope in A4)
A4 brings outdoor hot tubs and religious or ceremonial pools into Section 702. The tub itself must meet BS EN 60335-2-60. For an indoor tub, the bathroom approach in Section 701 is usually the better fit.
Treat the tub as a basin with zones around it. Check the zone figures in the current edition before setting out the supply.
- Hard-wire it where you can. A fixed supply stops people running the tub from an extension lead.
- Isolator. Fit it outside zone 1, reachable for maintenance but not from the water.
- RCD type. 30 mA, of the type the maker specifies. Pump and heater controls can produce DC residual current, so make sure no upstream Type AC device gets blinded.
- Earthing. Think hard before taking a PME earth outdoors to a tub. Many designers make the tub supply TT. If you do, keep it apart from PME-earthed metal so no one can touch both.
- Bonding. Check gazebo frames, handrails and lighting columns. Bond any that are extraneous-conductive-parts.
Regulation references: 702.415.2, 702.55.5, 411.3.1.1, 531.3.3
Construction sites (704)
Site supplies get run over, rained on and dropped in puddles, so the rules favour lower voltages and tough gear. BS 7375 gives the site code of practice.
- Portable tools: 110 V centre-tapped earth RLV is the normal UK choice, giving about 55 V to earth single-phase. Protective devices must break both lines and suit 110 V.
- Sockets up to 32 A: RLV, SELV, electrical separation or a 30 mA RCD.
- Sockets over 32 A: the circuit needs an RCD of 500 mA or less.
- Earthing: don’t use a PME earthing terminal unless every extraneous-conductive-part on site is reliably bonded to it. In practice most site supplies are TT.
- Kit: purpose-built site assemblies, BS EN 60309-2 plugs and sockets, heavy-duty flexes protected at crossings.
Regulation references: 704.410.3.10, 704.411.3.1, 411.8
Outdoor lighting and street furniture (714)
A4 confirms that Section 714 covers highway power supplies and street furniture as well as outdoor lighting. Road traffic signals sit within the section, though not within the outdoor lighting definition.
Lighting the public can reach now needs 30 mA RCD additional protection unless it runs on SELV. It counts as out of reach if live parts are beyond arm’s reach or inside a locked enclosure rated at least IK08.
Regulation references: 714.411.3.4, 415.1.1
Other locations: the points that catch people out
- Saunas (703): only the heater’s own controls go in the cabin. Cables near the ceiling must suit the heat there.
- Agricultural (705): livestock are more sensitive to touch voltage than people. Bond the floor grid and keep wiring away from animals and rodents.
- Caravans (708/721): on a PME site, make each pitch TT with an electrode whose resistance area doesn’t overlap the PME earth. The hook-up flex is one 25 m length (±2 m), no joints.
- Marinas (709): don’t connect an isolating transformer’s supply PE to the shore socket’s earth terminal, or galvanic currents can attack the hull.
- Medical (710): fully redrafted. Group 2 locations need two independent supplies to BS 8519 plus a UPS. For RCD-based fault protection in TT systems the touch-voltage limit is 25 V. Bonding resistances go on a schedule at every verification. Specialist work.
- Exhibitions (711): inspect and test every time a stand is built on site.
- ELV lighting (715): 12 V track draws big currents. Size for voltage drop and protect the ELV side against overcurrent.
- PoE (716): without a listed PSE, the source is limited to 60 V ripple-free DC in dry locations and 15 V elsewhere. Big bundles of powered cable run warm.
- Floor heating (753): follow the maker’s surface temperature limits and record the mat layout.
Regulation references: 703.512.2, 705.415.2, 708.411.4, 709.313.1.101, 710.313.1.102, 716.414.1.1, 753.424.3.1
See also: RCD selection in Section 3, TT and PME in Section 6, testing in Section 9.
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