"Pecanfan" wrote in message
...
OK, I've read everything there is to know about the subject on t'interweb
and I'm significantly more confused than when I first started.

Blank canvas - new bathroom - no earth at present. The ceiling is 2.9m
high
and the lighting is 12v IP44 rated with an external switch. There's
nothing
else electric in the bathroom other than the extractor fan, which is
double
insulated.

I have a metal bath, metal towel radiator (NOT electric), metal shower and
(obviously) metal taps. All supply and c/h pipework is copper, all boxed
in
above floor level, and the mains water supply to the building is plastic.
SO...

1. I gather I need to earth my lovely chrome towel radiator with an awful
green and yellow cable? How on earth (sorry!) do I do this without having
the earth cable dangling up my wall? Would it be sufficient to bond the
(microbore) pipework inside the boxing (approx 1ft below the towel
radiator
itself) or does the actual towel radiator need to have an ugly earth clamp
stuck to it?

My Collins DIY book shows each microbore pipe bonded AND the radiator too!
My bathroom is not new so there's no way I'm bothering with that: I've only
just
bonded the flow and return radiator pipes and the gas pipe by the CU, they
were
only bonded by indirect means before. Rumor has it that compression fittings
make
good metal to metal contact reliably, so I'm thinking that all this multiple
bonding
(i.e. 3 lots per adiator ) is a bit OTT. Dunno what the regs say exactly.

1b. If my towel radiator MUST be bonded, why doesn't it have a strategic
point onto which to attach an earth cable?

To make life difficult for us. It'll most likely be very well bonded via the
microbore anyway.

2. I read somewhere that if the earth cable is within conduit 4mm^2 is
sufficient. Since the earth cable will run (loose) within boxing around
the
room, does this count as conduit?

I heard it was 4mm2 if protected, but as small as 2.5mm2 if run in
conduit???
Something to do with =60% of the cross sectional area of the local
circuitry
( which is none in my bathroom, unless you count the ceiling light ). I
guess that
means that 2.5mm2 is more than sufficient if the only danger comes from
lighting
circuits.

3. OK, so I connect everything together with earth clamps and bits of
wire - where does this ultimately need to go back to? I've read it's NOT
a
good idea to take this back to the CU.

As the other poster said, it is not necessary AFAIK to take it take to the
main earth
terminal, the fact that all extraneous metal parts in he bathroom are all
connected
together is sufficient.

4. If I bond everything together within the boxing, to hide unsightly
earth
cables, will this be sufficient? (the boxing will have removable panels
at
strategic points) i.e. exactly how close to the taps, towel radiator,
shower etc. does the earth wire need to run?

Not sure about how close. If you have trouble fitting the clamps, post
again: I found out
that the ones that I bought needed disassembly then ressembly in a different
way to work.

Andy.

Think that's it! TIA,

Andy