In message ,
Andy Wade wrote:

Martin Angove wrote:

[OSG note (i) to Figs, 4a, 4b & 4c]

It is *probably* meant to guard against the situation where the
connection to the first service becomes loose.

I'd suggest it is meant to maintain the bonding to the other services in
the event that the clamp to an intermediate service is removed
(temporarily or permanently) in connection with work being done on that
service. E.g. if a metal service pipe is replaced in plastic the clamp
can be removed safely and continuity is maintained without the need for
any electrical knowledge by the plumber/gasfitter etc. The plumber
(etc.) would have to deliberately cut the wire to disrupt the bonding.


Good point, hadn't thought of that. I'm not sure how often that is
likely to happen though; on the incoming side, perhaps, but on the
outgoing side it'd have to be a pretty major refurbishment to warrant
replacing with plastic right back to the tap. Mind you, I can't see one
of those straps coming loose without an earthquake either :-)

A point arising though is what to do with the disconnected bond? You'll
be left with a length (inch to inch and a half) of G&Y which has been
stripped of insulation and hence requires protecting from damage and the
elements and accidental shorting on something it shouldn't. Would a tape
wrap be sufficient, or would we be looking at enclosing in some kind of
a box? Would a plumber necessarily think of such things?

Had a job last week where I renewed the bond to the water pipework. The
kitchen fitters (about 2 years ago) had simply disconnected the original
bond and left it dangling behind a unit. It was green 6mm2 and I needed
(for other reasons) to upgrade to 10mm2, but why on earth (sorry) did
they just leave it dangling when presumably it was previously attached?

I don't see that this in any way forbids the use of a properly-made
in-line joint in a bonding conductor. In any case the main bonding
conductor(s) have to be disconnectable from the main earth terminal for
test purposes - so there's one joint to start with...

Having said that, I have always run single continuous lengths for the
main bond, and have never jointed. I would consider a joint where
replacing the whole run would be impractical, but impractical does not
include "the run is 15m and I've only 12m of cable left on the drum".

I agree, but there's nothing in section 543-03 of BS 7671 -
"Preservation of electrical continuity of protective conductors" that
specifically bans such joints.

No, and I think I said that, or at least implied that, in my post. I was
just trying to avoid quoting large chunks of BS7671 ;-)

Hwyl!

M.

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Martin Angove: http://www.tridwr.demon.co.uk/
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