Bathroom Fan Isolators and cable colours

[Sparks]

Yes, it's me again!

When I wire my new extractor fan in the bathroom, I will be installing a fan isolator switch outside the bathroom.

I will need to bring the following both in and out... Permanent live Switched live Neutral Earth

The only three core and earth I can find has the colours Brown Black Grey (Bare earth)

This, I understand is the colours for three phase wiring? (Although Screwfix suggest it is used in two way lighting)

My house has both the old colours (Red/Black) and the new (Brown/Blue) (With the appropriate sticker on the consumer units, of course)

Can my new circuit use both the old and the new colours in the same cable, like this... Brown - Permanent live Black - Neutral Grey - Switched Live, sleeved in red or brown

If not (and I expect not) do I just sleeve with blue and brown each end of the cable?

Ta!

[Andy Wade]

Correct, just as old-colour 3&E cable had red, yellow, blue (the old

3-ph colours).

Also correct, all cores sleeved brown, of course.

No, you shouldn't be using old colours at all now. In particular you should use the grey core (sleeved blue) for neutral, not the black.

So no, like this:

- Brown - Permanent live - Grey - Neutral (sleeved blue) - Black - Switched live (sleeved brown)

Sleeved at the ends and any intermediate connection points.

[Sparks]

Thanks Andy - It just seems so wrong using a black wire for a live!

[Andy Wade]

Yes, it does go against the grain, but it's exactly what they do in much of the rest of the world, and we're just going to have to get used to it.