Which Cables Can I Use in the Bathroom? (AREI Zones)
XVB is always permitted, VOB in conduit only with restrictions. Learn which cable types are allowed in each AREI zone and what to watch out for.
XVB is always allowed — VOB only with restrictions
Bathroom electrical installations in Belgium are subject to special regulations. The key rule of thumb: XVB cable (sheathed cable) is permitted in all bathroom zones. VOB wire in conduit (Preflex) has restrictions — especially in hollow walls.
The AREI bathroom zones
The AREI defines three zones around bathtubs and showers: Zone 0, Zone 1, Zone 2 (bathtubs only), and the area outside the zones (Art. 7.1.3.2).
| Zone | Area | Permitted installation |
|---|---|---|
| Zone 0 | Inside the bathtub/shower | SELV ≤ 12V only, IPX7 |
| Zone 1 | Vertically above Zone 0, up to 2.25 m height | Fixed appliances ≥ IPX4; SELV sockets and SELV switches permitted (Art. 7.1.5.2c Nr. 2 and 4) |
| Zone 2 | 60 cm around Zone 1 — bathtubs only | Sockets with 30mA RCD allowed, appliances ≥ IPX4 |
Important: Zone 2 is not defined for showers (Art. 7.1.3.2 Nr. 3b). For showers, Zone 1 is followed directly by the area outside the zones.
Outside these zones, normal installation rules apply.
Cable types and their permissibility
| Cable type | CPR class | Zone 0 | Zone 1 | Zone 2 | Outside zones |
|---|---|---|---|---|---|
| XVB 3G2.5 | Cca | No | Yes | Yes | Yes |
| XVB 3G1.5 | Cca | No | Yes (lighting) | Yes | Yes |
| VOB in grey Preflex | — | No | Yes | Yes | Yes |
| VOB in green Preflex | — | No | No (hollow wall) | Restricted | Yes |
| H07Z1-U (halogen-free) | Cca | No | Yes | Yes | Yes |
Important notes on cable types
- XVB (sheathed cable): Always the safe choice. Suitable for flush mounting, surface mounting, and cable trays.
- Grey Preflex (standard conduit with pre-pulled VOB): Permitted in solid walls. Not allowed in hollow walls or suspended ceilings.
- Preflex Safe (green): In solid walls, Preflex Safe (Cca) is also permitted in Zone 1. The restriction applies to hollow walls (droogbouw), not the zone itself.
- H07Z1-U: Halogen-free wire, particularly recommended for sensitive areas. Note: H07Z1-U as a single wire does not inherently have a CPR class of Cca — the class refers to the cable system (wire + conduit). H07Z1-U in Preflex Safe achieves Cca.
Cross-section table
| Usage | Min. cross-section | Circuit breaker |
|---|---|---|
| Lighting | 1.5 mm² | 10A or 16A |
| Sockets | 2.5 mm² | 16A or 20A |
| Washing machine / dryer | 2.5 mm² | 16A (dedicated circuit) |
| Electric water heater (under-sink, ≤ 2 kW) | 2.5 mm² | 16A |
| Electric instantaneous water heater (18–27 kW) | 6 mm² (32A) or 10 mm² (40A, three-phase) | 32A or 40A |
30mA differential protection is mandatory
According to AREI Art. 7.1.4.3, all circuits in the bathroom must be protected by a 30mA RCD — no exceptions. This applies equally to lighting, sockets, and fixed appliances.
Warning: Even circuits that merely pass through the bathroom (e.g., cables to the attic) must comply with zone requirements if they run within the protection zones.
Equipotential bonding in the bathroom
Important: The AREI (Art. 7.1.4.4) requires supplementary equipotential bonding in the bathroom — all metallic parts (water pipes, radiators, bathtub, drain pipes) must be connected to each other and to the main earthing terminal via a protective conductor. Missing equipotential bonding is a common reason for inspection failure.