Which Cables Can I Use in the Bathroom? (AREI Zones)
XVB or VOB in conduit, with no metal elements: which wiring is allowed in bathroom zones 0, 1 and 2, how to install it and which RCD the bathroom needs.
AuthorStephan BehmWhich cables are allowed in the bathroom
In the bathroom you install wiring without metal elements: typically an XVB cable or insulated single-core wires (VOB) in conduit. Armoured cables and steel conduit are banned in the bathroom and up to 5 cm deep in its walls. Zones 1 and 2 only carry wiring that supplies equipment in zones 0, 1 and 2; zone 0 only carries the wiring of the SELV equipment allowed there. Every bathroom circuit is protected by an RCD of high or very high sensitivity located outside the bathroom. That is how Book 1 of the AREI/RGIE, Belgium's general regulations for electrical installations, regulates it in chapter 7.1.
Zones 0, 1 and 2
The official Dutch and French texts speak of volumes; in practice most people say zones. They depend on whether you plan a bath or a shower (subsection 7.1.3.2).
| Zone | Bath | Shower | What is allowed |
|---|---|---|---|
| Zone 0 | inside the bath | Shower tray at least 10 cm deep: its interior up to 10 cm above its base. Otherwise: up to 10 cm above the floor within 1.20 m of each fixed water outlet | Only fixed, permanently connected equipment on SELV (source outside zones 0 and 1), at most 12 V AC; no sockets, no junction boxes |
| Zone 1 | above the bath up to 2.25 m (or up to a higher fixed water outlet), including the space under the bath | within 1.20 m of each fixed water outlet, up to 2.25 m or up to a higher outlet | SELV equipment, SELV sockets and SELV controls; low-voltage equipment only if permanently connected and intended by the manufacturer for zone 1 |
| Zone 2 | 0.60 m around zone 1 | not defined | Fixed equipment, switches, SELV sockets; 230 V sockets only behind an RCD of very high sensitivity (≤ 10 mA) or each via its own isolating transformer up to 100 W |
| Outside the zones | rest of the room | rest of the room | General rules of Book 1 |
Fixed walls can limit the zones; the figures are in subsections 7.1.3.3 and 7.1.3.4. The required water resistance follows from table 7.3: zone 0 calls for external influence AD7 (at least IPX7), zones 1 and 2 for AD4 (at least IPX4). Exception per the footnote to table 7.3: low-voltage sockets in zone 2 and outside the zones may have degree of protection IPXX. The maximum SELV voltages are in tables 7.1 and 7.2. The equipment rules per zone are in subsection 7.1.5.2, points b to d. Distribution boards are banned in zones 0, 1 and 2, as is equipment that supplies or protects other rooms.
Cable types by zone
| Wiring | Zone 0 | Zones 1 and 2 | Outside the zones |
|---|---|---|---|
| XVB cable | only for zone-0 equipment, embedded in fixed walls | yes, if it supplies equipment in zone 0, 1 or 2 | yes |
| VOB / H07V-U in conduit | only for zone-0 equipment, in conduit in fixed walls | yes, if it supplies equipment in zone 0, 1 or 2 | yes |
| Single-core wires without conduit | no | no | no |
| Armoured cable, steel conduit | no | no | not in the room nor up to 5 cm deep in its walls |
For zones 1 and 2, subsection 7.1.5.2, point e, allows four installation methods: in conduit embedded in fixed walls (5.2.9.3), exposed or surface-mounted (5.2.9.5), in building cavities (5.2.9.9) and embedded without conduit (5.2.9.10). SELV wiring in zones 0, 1 and 2 needs protection by insulation as defined in subsection 4.2.5.4, point a, whatever the installation method.
What to check on the conduit
- Fire behaviour of the conduit: a conduit that contributes to flame propagation may only be used when embedded at least 3 cm deep in non-combustible material (5.2.7.4 and 5.2.9.3, point f). In stud walls and suspended ceilings you therefore need a non-flame-propagating conduit. The property of your pre-wired conduit (Preflex) is printed on the conduit and its data sheet.
- No loose single-core wires: conductors with basic insulation only, such as VOB, never go into a wall or cavity without conduit (5.2.9.9 and 5.2.9.10).
- Bundled cables: conductors and cables laid in bundles need at least property F2 or fire class Cca; those laid singly at least F1 or Eca (5.2.7.2 and 5.2.7.3).
- Through-runs: wiring that only passes through the bathroom to another room does not belong in zones 1 and 2. Route it outside the zones.
Cross-section and protection
The bathroom follows the same maxima as the rest of the home (table 4.11 in subsection 4.4.1.4):
| Use | Cross-section | Max. circuit breaker |
|---|---|---|
| Lighting | 1.5 mm² | 16 A |
| Sockets | 2.5 mm² | 20 A |
| Washing machine, tumble dryer (own circuit) | 2.5 mm² | 20 A |
| Electric floor or wall heating | by power | per table 4.11 |
| Instantaneous water heater, large boiler | by power and manufacturer data | per table 4.11 |
Appliances with a fixed location of 2600 W or more get their own circuit (5.2.1.2). Heating elements embedded in fixed walls are allowed outside zone 0 if covered by a metal grid connected to the supplementary equipotential bonding (7.1.4.5).
An RCD for every bathroom circuit
Subsection 7.1.4.3 requires one or more RCDs of high or very high sensitivity, 30 mA in practice, for every circuit that supplies the bathroom. The only exceptions are final circuits on SELV, with electrical separation or forming part of a safety installation. This applies equally to lighting, sockets and permanently connected appliances.
Two details decide the design:
- The RCD is installed outside the bathroom.
- In domestic installations it sits downstream of the RCD at the origin of the installation. The main RCD alone is not enough for the bathroom.
The same 30 mA RCD may also protect circuits in other rooms.
Supplementary equipotential bonding
Subsection 7.1.4.4 requires supplementary equipotential bonding in the bathroom: it locally connects the exposed conductive parts of electrical equipment to the simultaneously accessible extraneous conductive parts, such as metal water and heating pipes, a metal bath or a metal waste pipe. Exempt are SELV equipment, plastic pipes, radiators fed by plastic pipes and class II equipment.
How PlanElec helps with the bathroom
In PlanElec, assign each bathroom device its zone. The AREI/RGIE self-check then flags bathroom circuits without a 30 mA RCD and equipment not allowed in zone 0, 1 or 2, such as a mains socket or mains switch in zone 1. You choose cable type, conduit and installation method using the rules above. The inspection of the installation is carried out by the recognised inspection body. The rules covered are listed in what the self-check verifies.
Official source: AREI Book 1, version 06, chapter 7.1 and subsections 4.4.1.4, 5.2.7.2 to 5.2.7.4 and 5.2.9.