Bathroom zones / regs

[Colin Wilson]

Just wondering how interpretive you can be of the new zoning regs for bathrooms :-}

The light in ours would notionally fall under zone 2, being about 50cm outside zone 1, however zone 2 only appears to apply up to 2.25m high.

Our ceiling is 2.30m high.

Looking at the pocket guide, i'm not sure if it becomes a zone 3 which covers an additional 0.75m height, following the same 0.6m "radius" from the bath as shown on the diagram, or if the zone 3 markings only apply to adjacent walls as shown on the diagram...

Either way, it looks like a standard 240V lamp would be ok unless you start talking about the size of lamp fittings ! (which is likely to be a slim profile enclosed fitting by the time the wife finishes anyway)

Has anyone fitted a whirlpool bath recently ? the regs say under the bath is zone 1 if accessible without tools, but not what it's classed as if you _do_ need tools :-}

...also, are they typically LV or 240V these days ? (just trying to imagine the size of conductors required if it incorporated a heating element !)

Last but not least, what classes as Class I or II equipment these days for the purposes of cross-bonding ? - the wording of the regs seems to suggest either:

a) local cross bonding should go to all terminals of protective conductors within zones 1, 2 and 3

b) i'm misinterpreting it and you need to take the cross bonding all the way back to the consumer unit

[John Rumm]

If I understand what you are describing (i.e. a light offset to the side of the bath , but less than 0.6m horizontally), the the space directly above Zone 2 from 2.25m to 3m is Zone 3. Above that is out of the zones.

Mostly, in that the general requirements of BS7671 would apply. Those do include a requirement that fittings selected are appropriate for the location. So if it gets very steamy in there, something with better moisture ingress protection than a bog standard light may still be a good idea.

Outside of the zones. i.e. you can fit anything you like including a conventional socket.

Mains (in my limited experience of them). They have relatively modest requirements if they just have a pump, but can require fairly significant power if they are electrically heated.

Well not all terminals, but that all the CPCs of all the circuits that supply equipment within the zones should be included in the bonding.

So for example, if the only circuit was the lighting one, but there were two lamp fittings in the room, you would need one connection between the local eq bond, and the earth of the lighting circuit. This could be taken from any appropriate place where the circuit earth is accessible.

No need for an explicit connection to the CU. (even though you get an implicit one by virtue of the CPCs of any bonded circuits.

[Colin Wilson]

Cheers for that - I might have to see how the hell I can get an additional earth to the lamp then :-}

[John Rumm]

You may find it easier to intercept the supply cable to it at a convenient place. This could be just outside the bathroom if that was simpler.

(or wait for the 17th edition to take force - no EQ bonding required, but you will need RCD protection for all circuits in the bathroom including the lighting)

[Colin Wilson]

It probably wouldn't be too hard for me to do that - it's a downstairs bathroom, and there's a 2.5mm to a fused switch that used to supply a downflow heater, and the lighting was (IIRC) also run seperately direct from the CU.

My biggest problem would be finding and fitting RCDs in the CU !

[John Rumm]

Nothing to stop you having a RCD in an external enclosure and feeding the existing cable through it. (or installing a secondary CU fed either from a submain derived from a non RCD MCB on the main CU, or from split tails)

If the downflow heater is on its own radial, you may be able to squeeze a single module wide RCBO in the current CU (depends on brand of CU and if it can cope with tall MCBs). You could then fuse this down nearer the bathroom to run the lights in there and save the cost of a second RCBO.