On Friday, 29 May 2020 12:38:42 UTC+1, Roger Hayter wrote:
Robin wrote:

On 27/05/2020 13:51, Roger Hayter wrote:
Robin wrote:

On 26/05/2020 12:59, wrote:

Be aware that they will only reconnect your supply after the work if
your water & gas/oil are bonded.



and IIRC to current (continuous 10mm) standard

What does 'continuous' mean in this context? Surely it doesn't mean no
joints? Or does it means no thinner sections?

It means if your water bond is on the way to the gas, so you do it all
in one length, make sure it is one length(not cut). That way if someone
disconnects the water bond, gas is still bonded.

I think I learned that here, but I've seen it referenced elsewhere too.


Yes - sorry I was misleadingly vague.

AIUI it's not mandatory part of BS7671 but something that BS7430 and
Guidance Note 8 says "should" be done - and makes for a quieter life.

And while there's no regulation against joints in main bonding with
junction boxes (or chock strip) suitably labelled I'd extend with an
uninsulated crimp.

PS

Sorry too that for some reason I thought I knew UKPN was your DNO.
You mean if you fix a 2" X 3/4' chunk of brass on the wall with several
green and yellow wires going into it you would have to label it "safety
electral earth etc"? And should you enclose it to discourage
interference?

Yes it makes sense, though my electrican did not bother. Maybe he (or
I) might have done if it hadn't been in a workshop.


All I meant was that I agree with those who argue a screwed connection
in a main bonding conductor brings it within 514.13.1((ii) ("a point of
connection of every bonding conductor to an extraneous-conductive-part")
and so requires the warning notice. It can be argued the other way but
I was persuaded by the fact that the join must be accessible (else you
wouldn't use a screwed connection, would you?) so it makes sense to
require a warning notice there as at connections to pipes etc.

What happens in practice is of course another matter. But I've seen
labels used where the bonding used a combination of cable and pipe.

I don't know just what your chunk of brass was for but 514.13.1((iii)
provides that no label is needed for a MET by switchgear.

It's slighly interesting. The person who wired my house originally
took equipotential bonding remarkably seriously and throughout the house
(at least in all rooms with any CH pipes or extraneous metal work which
I think was everywhere except the conservatory) he ran a network of
10mm insulated earth wire in parallel with every bit of the socket
wiring plus to every pipe, even ones connected by copper back to the
boiler. If I felt like burning the insulation off I'd have about 10kg
of copper I've ripped out doing other jobs. A consequence was an earth
terminal block in almost every room and the electrician used one of them
which was actually directly connected to the supply earth block, rather
than pulling a new wire in from the supply board to do the one bit of
bonding the original owner forgot, which was the oil feed into the house
- one of very few that was actually required. Though since it goes to
the outside oil tank with no earthing to speak of it therefore creates a
new PME hazard. In the context a label saying this connection is
actually wanted might be sensible, though it would have to say why in
the context of dozens of other pointless earth labels.

When you've finally ripped it all out, then the regs will require equipotential bonding in all rooms.


NT