I know this query has come up lots of times, but I can't find an answer
to the same situation!

I've re-wired the bathroom; I now have

Central light, running to switch outside bathroom. From light fitting,
3-core and earth runs to triple-pole isolator (metal back box) then to
humidistat fan.

Shaver socket, with isolating transformer (also in metal back box)
connected to lighting circuit under floor via junction box

Lamp over the sink ("correct" bathroom type), cable run from lighting
junction box under the floor.

All of the above in either zone 2 or 3.

All pipework etc. connected equipotentially with 10mm earth cable.

Apart from connecting up earth in the T&E to back box, light fittings
etc., do I need to run a separate earth from/to anywhere else?! I was
confused by the Mike Lawrence book which shows a separate earth (?4mm)
running to the equipotential earthing from the back of a socket.

Thanks very much,
Nathan

On 21 Feb 2006 03:15:13 -0800 someone who may be "Nathan
Critchlow-Watton" wrote this:-

Apart from connecting up earth in the T&E to back box, light fittings
etc., do I need to run a separate earth from/to anywhere else?!

You should really run a supplementary bonding conductor to the earth
terminal of the transformer, though you will probably only get it
into the terminal by removing some of the "strands".

If the lights are Class I you should connect a supplementary bonding
conductor to their earth terminals.

I was
confused by the Mike Lawrence book which shows a separate earth (?4mm)
running to the equipotential earthing from the back of a socket.

Sockets in a bathroom? What sort of sockets?

The thread, "Elecric shower blown fuse" refers to a fairly well
known diagram of supplementary bonding and extracts from a book.
Have you studied that? Do you have any questions on it?


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54