installing main earth bonding conductors to gas and water services

[securespark]

There is no such thing as a "main Earth". It is called the Earthing conductor.

FFS .....

 

[EFLImpudence]

They do make up loads of carp.
An NIC spark had kicked off on a job I was on because a feed to a boiler had been piggy-backed off a 16A circuit feeding one socket.
When I suggested it was fine and showed him the OSG, he snorted,
"WE don't follow that piece of rubbish. Only the regs."
He was adamant it was non-compliant.

 

[Taylortwocities]

There is no such thing as a "main Earth". It is called the Earthing conductor.

It’s always easier to snipe from the sidelines than actually contribute something.

 

[Risteard]

It’s always easier to snipe from the sidelines than actually contribute something.

You were correcting the poster about Earthing and bonding but using incorrect terminology nonetheless.

 

[securespark]

I said to the bloke If you only work from the regs and know them well, you'll be able to tell me which regulation this is non-compliant with then, won't you?
He stood there, mouth moving but nothing coming out.

 

[AndyPRK]

If you connect an TN-C-S earth to a gas pipe before the isolation block, and the TN-C-S earth is lost, then it can rupture the gas pipe with explosive results, one does need to be careful that a gas pipe can't become the earth for the whole street.

And in practical terms, how do you do that?

 

[JohnW2]

I learnt at college in the 80s that if you are running from one pipe to another (eg gas to water) then best practice is to make an unbroken loop around the screw so that if the connection loosens, you don't lose the connection to the pipe at the end of the cable.

There's obviously at least some sense in that. However, if one of the intermediate connections 'loosens' (to the extent of there not being an electrically satisfactory connection between conductor and pipe), then one of the pipes will lose it's effective connection to the cable, even if it's not the pipe at the end of the cable!

However, that doesn't alter the fact that there is no regulatory requirement for the cable to be continuous.

Kind Regards, John

 

[ericmark]

In my old house there was an isolating block, so was just a case of ensuring the earth wire is connected to correct side. I have not as yet found a house without the isolator so never needed to worry about what to do if missing.

New house is oil.

 

[JohnW2]

In my old house there was an isolating block, so was just a case of ensuring the earth wire is connected to correct side. I have not as yet found a house without the isolator so never needed to worry about what to do if missing.

What sort of "isolator" are you talking about - and what do you regard as being "the correct side"?

Kind Regards, John

 

[securespark]

if one of the intermediate connections 'loosens' (to the extent of there not being an electrically satisfactory connection between conductor and pipe), then one of the pipes will lose it's effective connection to the cable, even if it's not the pipe at the end of the cable!

That goes without saying. The point is that, were it done with two separate conductors in the first bonding strap and that point came loose, BOTH would lose their connection.

 

[JohnW2]

That goes without saying. The point is that, were it done with two separate conductors in the first bonding strap and that point came loose, BOTH would lose their connection.

Yes, that might be the case. However, the point surely is that one doesn't want any pipe to end up unbonded (i.e. one, rather than two, unbonded extraneous-c-ps is still not acceptable), so one needs to address the quality of the connections to the pipes, regardless of how the cables are arranged (even if each pipe had a separate cable back to the MET, one of them could 'become loose' if not done properly).

In any event, what we are now discussing is rather different from what the OP was talking about, which was a join in the cable run back to the MET - and, despite what Andy suggested, there is no regulation which forbids that.

To keep this in perspective, there are virtually always going to be a number of screwed-terminal joints in conductors between a bonded pipe and the installation's 'earth' (be it the DNO's PEN or cable sheath, or a local TT electrode), so we're only talking about 'one more'.

Kind Regards, John

 

[EFLImpudence]

There is also the point that other metal parts (except gas pipes) can be used as a bonding conductor in which case it is impossible for it to be continuous with no joints.

A lot of things are good ideas but not required by the regulations.

One such thing might be inserting a length of plastic pipe in the water supply (again, not the gas) so that main bonding is not required at all.

 

[JohnW2]

One such thing might be inserting a length of plastic pipe in the water supply (again, not the gas) so that main bonding is not required at all.

You might be interested in this (click here) . Although it may be a 'recommendation', rather than a 'requirement' (both words appear in the title), it appears that, since 2015, it has been recommended/required that ...

...Provision of earth terminal requires that where a metallic gas service is provided to a consumer’s premises with a PME earth terminal, an insulated insert should be fitted in the gas service.

... but this one seems to be a 'requirement' ...

Clause 11.2.1 states: …insulating fittings shall be installed in all metal pipe, whether gas carrying or containing a PE liner, capable of providing electrical continuity between earth and the above ground pipework.
Clause 11.2.2 states: Insulation fittings shall be installed in an accessible location as close to the pipes entry into the building or, in the case of external pipework, as close as possible to the pipes exit to the ground and upstream of any ECV. The uninsulated section of the exposed pipe shall be as short as possible.

I wonder if this is now being done routinely with new gas installations?

Kind Regards, John

 

[EFLImpudence]

You might be interested in this (click here) . Although it may be a 'recommendation', rather than a 'requirement' (both words appear in the title), it appears that, since 2015, it has been recommended/required that ...
... but this one seems to be a 'requirement' ...

Yes, but then up until and including the BYB 544.1.2 said "insulating section" and required the Main Bond to be on the customers side of that insulating section.
We have many times discussed how this was wrong.

The BBB 544.1.2 now says "isolation point".
I am not sure what that is; it could be the gas tap; but still requires the Main Bond on the customer's side. Although, of course, with a now unmentioned "insulating section" that means the customer's side is not an extraneous-c-p so does not require a Main Bond in the first place.

I wonder if this is now being done routinely with new gas installations?

I don't know.
The gas people presumably want it but if there is still a metal gas pipe entering the premises then that will still require a Main Bond - but the electricians will probably not realise and bond in the wrong place as they always have.

 

[EFLImpudence]

Mmmmm.

From your link:

"To summarise, the two main reasons for insulating inserts/insulation joints in metallic pipework are to prevent corrosion and to prevent pipes being used as a path for fault current. Also, the main protective bonding requirements in BS 7671:2008+A3:2015 are understood to be written on the expectation that insulating inserts /insulation joints are installed in metallic service pipework."

Or maybe not.