Andy Wade wrote:
Lobster wrote:

Secondarily - I'll bond the H&C pipes at the sink; but if I also have
a metal shower bar fed by copper pipes (no plastic anywhere in this
bathroom), do I really need to bond the H and C pipes to that as well?
Doesn't the shower valve act as conductor (or could, eg, PTFE tape in
the fittings potentially act as insulator? Indeed; do both the H&C
pipes feeding the plastic bath also really need to be bonded, given
that they will already be connected by copper pipe under the floor, by
virtue of the sink bonding?

Judgement and common sense have to be applied here. Ask yourself "could
a plumber working here easily negate the bonding?" You can rely on
short lengths of copper pipework, including soldered joints, that don't
disappear off into the distance. The bonding must be "in close
proximity to the location" as it says in the OSG. I would not rely on
continuity through compression fittings, and certainly not through tap
connectors which could interpose some horrible mix of boss white, hemp,
PTFE and fibre washers in the way of sound electrical connection.

Thanks, Andy and Andrew - that's been really helpful. (I did manage to
get a single length of cable through the roofspace/cavity
wall/underfloor to all necessary locations in fact, so I'm quite chuffed
with that!)

Given what you say above about what does that say about where you should
ideally apply the pipe clamps under the bath/sink taps: above or below
the isolation valve, which we have to assume may also be a "horrible mix
of boss white, hemp, PTFE and fibre washers in the way of sound
electrical connection"!? Should it be above them to ensure hopefully
the taps are at equal potential? (But aren't the taps' electrical
continuity also still likely to be compromised by PTFE etc??) Bit confused!

David