Installing an extractor fan in a bathroom or wet room isn't as simple as choosing a model and placing it where it looks best. Bathrooms are considered high-risk environments due to the presence of water, and this proximity to moisture demands stringent safety considerations. To ensure that electrical installations such as extractor fans, lighting, or heaters are both safe and compliant with UK regulations, the location of installation is critically important.
Fortunately, the regulatory framework set out in BS 7671 – 18th Edition Wiring Regulations, specifically Section 701: Locations Containing a Bath or Shower, offers detailed and clear guidance for electricians and installers.
Below, we explore the concept of bathroom electrical zones, IP ratings, and the safe placement of electrical equipment based on risk assessment within these defined zones.
Understanding Electrical Safety Zones in Bathrooms and Wet Rooms
Bathrooms and wet rooms are classified into distinct zones, each representing a varying level of risk based on proximity to water. These zones determine what type of electrical equipment can be installed, including extractor fans and lighting, and what level of protection (IP rating) is required to mitigate the risk of electric shock or short circuits.
These zones provide a standardised way of determining which types of appliances are suitable for installation and where. While bathrooms are divided into Zones 0, 1, 2, and the ‘Outside Zone’, wet rooms typically skip Zone 2 due to the absence of shower trays or bathtubs that contain water within a fixed boundary.
⚠️ Please note: This guide provides general recommendations. Because bathrooms vary greatly in layout and structure, only a qualified and registered electrician should carry out electrical work to ensure full compliance with current safety standards and individual site considerations.
IP Ratings: What They Mean and Why They Matter
Before reviewing the individual zones, it's essential to understand IP (Ingress Protection) ratings, a universal classification used to denote how well an electrical product is sealed against dust and moisture.
An IP rating consists of two digits:
The first digit refers to protection against solid particles (not relevant for this guide).
The second digit indicates resistance to moisture and water.
In the context of bathroom installations, we focus on the second digit, which will appear in the format IPX4, IPX5, etc. A higher number denotes a higher degree of water protection.
IP Ratings for Bathroom Environments:
• IPX0 - no protection from liquids
• IPX1 - protection against vertically falling drops of water (e.g. condensation)
• IPX2 - protection against direct sprays of water up to 15 degrees from vertical
• IPX3 - protection against direct sprays of water up to 60 degrees from vertical
• IPX4 - protection against water sprayed from all directions - limited ingress permitted
• IPX5 - protected against low pressure jets of water from all directions - limited ingress permitted
• IPX6 - protected against high pressure jets of water (use on ship deck) - limited ingress permitted
• IPX7 - protected against the effects of immersion between 15cm and 1m
• IPX8 - protected against long periods of immersion under pressure
Breakdown of Bathroom Zones:
Zone 0: High-Risk Immersion Area
Zone 0 refers to the interior of a bath or shower basin, i.e., any space that can hold standing water.
Requirements:
- Electrical products installed in this zone must be SELV (Safety Extra-Low Voltage), not exceeding 12V.
- The product must be rated to IPX7 as it must withstand immersion up to 1m in depth.
- Applicable to both bathrooms and wet rooms, this is the most restrictive area and requires maximum caution.
Zone 1: Splash and Spray Area
Zone 1 is the area directly above Zone 0, extending up to 2.25 metres vertically from the floor and including the full horizontal footprint of the bath or shower tray.
In wet rooms, this also encompasses the area around the drain point, extending outward in a 1.2m radius.
Requirements:
- Devices must be rated IPX4 or higher.
- Products can operate on mains voltage, provided they are connected via a 30mA RCD/RCBO-protected circuit.
- If low voltage appliances are used, the transformer must be installed outside Zones 1 and 2.
- In cases where bathtubs are free-standing, the space beneath the tub is classified as Zone 1 unless the underside is fully enclosed with a secured panel accessible only by tool or key, in which case it may be considered part of the Outside Zone.
Zone 2: Perimeter Protection Area (Bathrooms Only)
Zone 2 extends 0.6 metres horizontally beyond the perimeter of Zone 1 and continues up to the same height limit of 2.25 metres from the floor.
Wet rooms do not have a defined Zone 2 and instead skip directly to the Outside Zone due to their open layout.
Requirements:
- As with Zone 1, equipment must be rated at IPX4 or greater.
- All circuits must be protected by a 30mA RCD or RCBO.
- Transformers must remain outside this zone.
- Zone 2 is typically used for installations such as lighting or fans adjacent to showers, providing a moderate level of moisture protection.
Outside Zone: Beyond the Boundaries
Any area beyond Zone 2, including above the 2.25m vertical height threshold, is classified as the Outside Zone. This zone encompasses the remaining areas of the room not included in Zones 0–2.
Key Considerations:
- There is no specific IP rating required in this zone.
- Standard bathroom lighting and extractor fans with a rating < IPX4 are permitted.
- Portable electrical devices are generally not allowed, except for shavers and electric toothbrushes.
- Sockets (e.g., 230V) are not permitted unless located at least 3 metres away from the edge of the bath or shower and protected via a 30mA RCD/RCBO.
Pull Switches and Switch Gear
Pull switches controlling lighting or shower functions should be mounted in the Outside Zone (above 2.25m), with only the operating cord entering Zone 2.
Clarifying the “Outside Zone” Further
The Outside Zone is split into two conceptual parts for clarity:
Part 1:
- The zone begins where Zone 2 ends, extending horizontally up to 3 metres.
- If a wall is encountered before reaching 3 metres, the Outside Zone ends at that wall.
- Items such as towel rails and 230V electric heaters are allowed but must be:
- Permanently connected (e.g., via a flex outlet).
- Powered through 30mA RCD/RCBO protection.
- Switched either inside or outside the bathroom based on customer preference.
Part 2:
- This includes all space more than 3 metres from the bathtub and the ceiling space above Zone 1 or 2.
- No IP rating is required for equipment in this zone, provided installations remain clear of direct water sources.
Final Word: Always Consult a Qualified Electrician
While this guide provides a comprehensive overview of bathroom zones and the correct placement of extractor fans and other electrical equipment, it should not be used as a substitute for professional assessment.
Only a certified and experienced electrician can ensure that your bathroom installation is carried out in full compliance with the 18th Edition of BS 7671 and adapted to the specific conditions of your space.
Electrical safety in wet environments is not negotiable—proper zoning and appropriate IP ratings can mean the difference between a safe, long-lasting installation and a hazardous one.
Below is a selection of what we consider the best bathroom extractor fans for Zone 1 compliance: