main bonding issue

[cstokes]

Hi all,

After having just removed my kitchen sink I found the following (please let image link work!!!)...

Originally I could only see the newer stop cock so was going to attach the main earth bonding to the mains pipe side of it. Now I find the original earth wire attached to the (slightly) visible original stop cock (made of lead) which is half burried in the ground. Is it ok to attach the new earth bonding to the correct side of the new stop cock and basically ignore the old stop cock which is completely unusable and untouchable!

Any help appreciated.

Thanks
Chris

 

[Lectrician]

You would struggle, as to comply, you would need to put the clamp after the tap, but before any tee's - not a lot of room for that

But, if you put it after the old tap, you have bends in the pipe to contend with - clamps don't like bends!

A little re-piping maybe

 

[mapj1]

Forget the old tap. The problem with the house side of the new one is that compression Tee, in prctice it almost certainly does connect through perfectly well, but it might be full of ptfe tape and verdigris, so interupting connection.
I'd second the other suggstion, ideally replace with a soldered tee, but add as a second choice clamping onto both of the other sides of the compression tee, would achieve the same effect, though slightly less ideal. Don't bond before the new tap - I can see the PTFE tape...
Use damp condition (blue label?) clamps, this looks like a wet corner.

 

[ban-all-sheds]

Take your photo off to the plumbing forum for proper advice re the pipework, but my 2-pennorth is that you should take the opportunity to get rid of the first stopcock (p*ssed-off you would be if it sprung a leak after you cover it up again), and all those compression joints. If you use soldered ones then you can get one of those nifty joints with a built in socket for soldering in a bonding cable.

 

[fireman22]

if you don't want to disturb any of your pipework, fit two clamps one to each piece of 15mm pipe leaving that tee. Then your main 10mm earth cable can be linked across the two don't cut the 10mm earth cable though.

 

[Damocles]

Did anyone notice a bit of conflicting advice here? I agree there is a problem with the curve of pipe before the new stopcock. Someone also said do not bond at this point because of the ptfe in the stopcock nut which could very well be insulating the incomiing pipe from the stopcock.

Well, ok, but if one joint is ptfed then probably lots of others are too. It is not likely there will be continuity throught the pipework. How does the fact of the stopcock being insulated from the section of incoming pipe invalidate connecting the earth bond to that pipe? You will still have achieved the objective of neutralising any voltage coming into the house on the pipe.

 

[Lectrician]

I think PTFE on a compression fitting is unlikely to cause a non-conductive situation.

The copper pipe will still be in tight contact inside the fitting, along with the compressed olive. The Locknut doesnt make good contact the pipe anyway - if it did, you would never be able to tighten it!

It is the olive that secures the assembly.

 

[plugwash]

Take your photo off to the plumbing forum for proper advice re the pipework, but my 2-pennorth is that you should take the opportunity to get rid of the first stopcock (p*ssed-off you would be if it sprung a leak after you cover it up again), and all those compression joints. If you use soldered ones then you can get one of those nifty joints with a built in socket for soldering in a bonding cable.

iirc thought crimp the cable in not solder it

 

[Damocles]

Thats all very well but I have found more than one compression fitting where ptfe has been wrapped all round the pipe and olive. People do this. Push fit joints are also not guaranteed to make electrical contact, even most of the metal bodied ones. So the question is still a real one even if in this case the stopcock does conduct through. I reckon it does not matter, so long as the incoming pipe is earthed. opinions?

 

[Lectrician]

Two ways of thinking...

We have to bond at the said point.

Is to 'earth' ingoing ot outgoing or both?

For a PME install, the bond can provide an alternative path for fault current. We also have to 'neutralise' the incoming pipe.

But we have to bond even if the pipe entering the property is plastic, and copper in the property.

So, it seems we need to bond for both directions so to speak.

 

[mapj1]

As I understand it, The Idea is to prevent the export of fault voltages at the boundry of the equipotential zone (where pipes enter or leave the house ), not to blow the fuse if the immersion heater/shower/whatever goes faulty and tries to make the tank live- that is done by the earth connection in its cable. Bathroom X bonding reduces this risk further in the one place you are really exposed.
Otherwise we'd be bridging out each section of plastic pipe we found between incomer and rest of house..
Actually as both sorts of fault very rarely persist undiscovered for long, the true risk is mercifully small, whatever you do, so lose no sleep.

(and PTFE is often found over the olive if the pipe has been scratched in cutting typically old pipe re-jiggend and junior hacksaw used tight in corner etc. replace with solder joins if you can. - and in extremis don't forget the dry bread trick for soldering if you can't get the water to shut completely off - stuff the pipe with bread, solder fast with as much gas as you can get on it, and as a last act convert bread to toast, and flush it out through the drain tap..)