Earthing through plastic pipe

[TimW]

There was an ancient (1950s) steel pipe bringing mains water into my house under the front room and then up in the cup'd under the stairs. There there was a stop c*ck and it went into copper pipe and onto the copper a large sleeved earth wire was connected with a tag on saying "Do Not Remove".

The steel pipe was leaking so I have taken it all out and replaced with blue plastic pipe. Was looking at the earth arrangement and wondering if I need to earth the wiring in another way, into the ground or something, or are we still earthed through the water in the plastic pipe out to the outside world?

TW

[tabbypurr]

Water is NOT an adequate earth. An old electrical install with no earth is not safe.

NT

[TimW]

So what would be an adequate earth? TW

[TimW]

and because the pipework is earthed - that doesn't mean that the incoming main is THE earth for the house, does it?

TW

[alan_m]

Was it used as the earth or just a bonding point?

[Robin]

Depends :)

That may have been just bonding of the incoming metal water pipe. If so there may be no need for it *if* you've now got all plastic. If not best to attach the wire to where copper water pipe starts again to maintain equipotential bonding. See

OTOH it may be - if it's an old house - the water pipe was part of (or even all of!) the earthing for all your wiring. If so you may need something to take its place - and PDQ if it was all you had.

Best place to start is what sort of earthing you have

If you aren't sure post links to some pictures.

[tabbypurr]

is not safe.

It depends on your install. Maybe an earth rod plus RCDs/RCBOs on all circu its. If your install uses the waterpipe as the main earth - which we can't be sure of at this point - it may have no RCD protection. Recommend posting a clear pic of the fusebox on here, plus the supplier's incomer.

As has been said it's also possible it's a modern install and the connectio n is just an equipotential bond. We don't know yet. The seriousness of havi ng no earth and an old fusebox means show us pics without delay. Yes there may be earthing elsewhere too.

NT

[John Rumm]

You have several possibilities here, ranging from mostly all ok, not much to worry about, to, you now have seriously defective electrical installation that will be a potential danger to life.

Needless to say, working out which is the first priority. :-)

The links Robin posted should help you identify the type of earthing system you have. If it turns out to be one of the TN variants, then you have not much to worry about. If its TT and the rising main was your main earth connection, you need to take some immediate steps to make it safe.

[Brian Gaff (Sofa 2)]

No you are not earthed by the water, not in my experience at any rate. Brian

[Brian Gaff (Sofa 2)]

I've often wondered what they do these days as people tell me you can see the plastic pipes coming up for the services in new builds. Maybe they all have some kind of local Earth spike or are they all joined together these days and earthed at intervals down the road? Interesting. Brian

[Tim Watts]

Earth rod and required RCD measures if you are a TT installation.

But are you maybe a TN-C-S or TN-S (supplier provided earth) and this clamp was merely equipotential bonding?

[Dave Plowman (News)]

It was common many many years ago to provide the earth via the water pipe. Not so today. Get your leccy board in to sort it out.

[Dave Plowman (News)]

It's not the water which provides the earth. It's the metal pipe in contact with the ground over a long distance.

[Tim Watts]

Going to add - if you can't work it out, best call a local sparky around asap to check it out. The worst case scenario as others have mentioned is a very dangerous installation.

[John Rumm]

Typically the earth will be provided by the electrical supplier, using their combined Protective Earth and Neutral conductor. Thus giving the consumer a TN-C-S / PME earthing system.

If the pipework in the house is metal, then it still need equipotential bonding since its capable of introducing a voltage into an equipotential zone from elsewhere in the house even if it can't do it from external to the property due to the plastic services.

If the pipework in the property is all[1] the plastic, then the pipework will not be included in the equipotential bonding.

[1] No need for EQ bonding in cases where the pipework is all plastic but with only "show work" in copper.

[Chris Green]

That is a bonding connection, not an earth connection (I hope).

[dr.j.r.stockton]

All more erudite considerations apart, the Water Boards do not guarantee that their water will be present at all times that the electricity is on.

[TimW]

This is the supply in the porch:

Two substantial earth cables from the black box, one going to the box of trip switches, the other just dangling, redundant from the old economy 7 circuit or something.

Can wiser eyes than mine declare the type of earthing arrangement?

RW

[Andrew]

Does the black cable that feeds the companies 80 amp fuse come in from underground ?.

If so, you probably have a PME arrangement. In fact the 10mm earth cable going into that 80 amp fuse block seems to confirm it.

The CU and meter look reasonably modern (-ish). The ring mains seem to be protected by a residual current device of some sort. Is RCCB an older name for RCD ?. Not sure.

Curiously there are Wylex MCBs and an MK one for the immersion. I didn't think they were physically compatible. Adam will know.

[Robin]

That looks promising (but also a bit of a dog's breakfast). But I'd rather leave it to those who have seen an awful lot more of them to advise the next step.

On a point of detail, can you see/work out where the wire connected to the copper pipe comes from?