Only separated extra low voltage selv devices are allowed in this zone but any transformer must be located beyond zone 2.
Bathroom electric towel rail regulations.
This zone has the same requirements as zone 1.
701 512 3 for zone 2 says switchgear and accessories may not be installed in zone 2 there are some exceptions for selv and shavers but not a towel rail.
Electric and gas water heaters in a bathroom must be fixed and permanently wired unless they are powered by a socket fitted three metres from a bath or shower.
However the main part of the wiring has been done by a electrician and is up to regulations recently required.
This is the area above or either side of zone 1 extending up to a height of 3000mm and extending horizontally to 600mm.
Normally to put a heated towel rail in a bathroom then the towel rail flex would go in a flex out let and from there the fuse would be out side the bath room the end.
If you were to install a heated towel rail in this zone it would need a rating no lower than ipx4.
Zone 1 is the zone above your bath or shower to a height of 2 25m.
Zone 2 stretches to a 0 6m outside your bath or shower and above your bath or shower if over 2 25m.
Heaters and towel rails central heating is the safest way to keep a bathroom warm.
But if you do have an electric heater it must be fixed at a safe distance from the bath or shower.
Alternatively put the towel rail in zone 2 with a sw spur or isolator switch more than 600mm from the bath shower so that it is no longer in zone 2 but still near the towel rail.
The minimum ingress protection rating here is ipx4.