On 05/05/2020 12:36, Dan S. MacAbre wrote:

I've a question about the earthing connections on our domestic plumbing.
Â*I can see that there is a wire in parallel to our water meter, but I'm
not sure that this can be the main earth because the supply pipe is
plastic.Â* I can also see a wire going into the wall under the sink, so
my assumption here is that it mainly uses the electrical earth.Â* But
there are speedfit connectors under there, which I expect are not
conductive, so there are parts (e.g. pipes feeding taps) that are
isolated from the rest.Â* I'm not worried about this (although perhaps I
should be?)

Generally nothing to worry about, if all we are discussing is
equipotential bonding.

, since all this was supposedly done by professionals;

Given many of them seem to flounder a little on this particular subject,
that is not always an assurance of anything!

but I
thought I'd ask here if every single section of pipe is meant to be
individually earthed,

Short answer - no.

or if that would not really be practical.Â* Does it
even make sense to earth, for example, braided tap tails?

Not really.

Firstly, this is not about earthing as such, but equipotential bonding -
different things, with different objectives that work in different ways.
However they do often use the same green/yellow insulated wire, and
there are situations where the systems interact.

In its simplest terms, earthing is designed to prevent electrical fires,
and limit the maximum duration of a an electric shock.

Equipotential bonding is designed to limit the magnitude of an electric
shock (i.e. reduce the current that can flow into the victim, by
limiting the voltage (or potential difference) across their body).

EQ bonding is used in places where you are likely to be more
unacceptable to the influence of a shock (e.g. when wet / naked). The
primary question ask when deciding what needs bonding, is "Is this
conductive part actually capable of introducing a potential into the
area". So a length of metal water pipe that comes from elsewhere in the
house to your bath tap, certainly could, and hence needs bonding. A
short section of copper "show work" pipe on the end of a feed in
plastic, does not, since it can't bring a potential in from outside the
zone.

Have a read through this for a fuller explanation:

http://wiki.diyfaq.org.uk/index.php/...ng_and_Bonding


--
Cheers,

John.

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