Earth wire on gas main pipe - advice on regs sought

[lorry108]

Hi there

I've had a new boiler installed and the electrician on the job noticed that the gas main wasn't earthed, which I paid him to do.

British Gas have since said that the earth wire should not have been attached to/run along the gas pipe. He said that according to current regs, there should be a 25mm gap between the gas pipe and the earth wire (because the earth wire has a current and may act as an ignition if there is a gas escape).

Also, BG said that the wire no longer needs to run all the way to the gas meter (as the electrician had done), but that it could be cut off at near the boiler (I didn't ask him how near unfortunately).

Can anyone verify this advice or recommend who I should contact to get a definitive answer?

Many thanks
lorry108

 

[riveralt]

British Gas have since said that the earth wire should not have been attached to/run along the gas pipe. He said that according to current regs, there should be a 25mm gap between the gas pipe and the earth wire

For Electric cables Separation of at least 25mm to be provided for domestic gas pipework up to 35mm....For pipework over 35mm then 50mm of separation is needed.

Also, BG said that the wire no longer needs to run all the way to the gas meter (as the electrician had done), but that it could be cut off at near the boiler (I didn't ask him how near unfortunately).

The main protective bonding conductors are required to connect metal gas installation pipes to the main earthing terminal, where there are extraneous conductive parts. The connection is normally made within 600mm from the meter.

 

[ban-all-sheds]

For Electric cables Separation of at least 25mm to be provided for domestic gas pipework up to 35mm....For pipework over 35mm then 50mm of separation is needed.

OOI, does the same apply if you use DI cable, or put it in conduit?

 

[riveralt]

For Electric cables Separation of at least 25mm to be provided for domestic gas pipework up to 35mm....For pipework over 35mm then 50mm of separation is needed.

OOI, does the same apply if you use DI cable, or put it in conduit?

Seperation distance can be reduced if the gas pipe is pvc wrapped or a panel of insulating material is interposed...OSG

 

[lorry108]

Hi again

Riveralt, could you let me know which regulations you are quoting? Is it possible the Electrician is following some other regulations?

Many thanks
lorry108

 

[riveralt]

Hi again

Riveralt, could you let me know which regulations you are quoting? Is it possible the Electrician is following some other regulations?

Many thanks
lorry108

Its on page 18 of the IEE red On Site Guide book which he should have - and the reference is (BS 6891:2005 installation of low pressure gas pipework in domestic premises clause 8.16.2)

 

[lorry108]

British Gas have since said that the earth wire should not have been attached to/run along the gas pipe. He said that according to current regs, there should be a 25mm gap between the gas pipe and the earth wire

For Electric cables Separation of at least 25mm to be provided for domestic gas pipework up to 35mm....For pipework over 35mm then 50mm of separation is needed.

Also, BG said that the wire no longer needs to run all the way to the gas meter (as the electrician had done), but that it could be cut off at near the boiler (I didn't ask him how near unfortunately).

The main protective bonding conductors are required to connect metal gas installation pipes to the main earthing terminal, where there are extraneous conductive parts. The connection is normally made within 600mm from the meter.

Okay, so now I'm really confused. Just had another British Gas engineer over and he said that the earth bonding DEFINATELY needs to run along the gas main because that's it's purpose. If there's an electrical charge from another source of electricity, the earth bonding will solve the problem (sorry I can't remember what he said exactly - something like 'the earth bonding will earth the charge'). He said that those guidelines refer to electrical wires and NOT to earth bonding. Any ideas?

 

[riveralt]

So one BG engineer says one thing and another say something else:
Here is wikis view on the subject:

http://www.diynot.com/wiki/electrics:main_equipotential_bonding

 

[Steve]

The bonding is there for one purpose only. All metal parts that enter your house have the potential to bring in a voltage potential from outside. Therefore to eliminate the risk of shock, we create an equipotential zone in the building, by linking all the metallic parts together with 10mm where they enter. So your earth wire must be connected close to the gas meter on your side of it. Where it runs after that, I dont know if there are any regs. Others will. I suspect its a gas reg, not an electrics reg.

My earth bond runs with the pipe, but inside trunking stuck to the wall. You could do this job yourself.

The stuff about a charge along the pipe is total bobbins. Pipes dont develop a charge along them, and even if they did, what good is a length of INSULATED copper wire? And this would mean my gas installation was about to blow up due to built up charge. . .

 

[lorry108]

The bonding is there for one purpose only. All metal parts that enter your house have the potential to bring in a voltage potential from outside. Therefore to eliminate the risk of shock, we create an equipotential zone in the building, by linking all the metallic parts together with 10mm where they enter. So your earth wire must be connected close to the gas meter on your side of it. Where it runs after that, I dont know if there are any regs. Others will. I suspect its a gas reg, not an electrics reg.

My earth bond runs with the pipe, but inside trunking stuck to the wall. You could do this job yourself.

Thanks Steve, very helpful. I'd feel a bit aggrieved to do the trunking myself since I've paid £3k for a new boiler, powerflush etc. but I take your point. The thing is, we only installed the earth bonding because the electrician (rightly) said that it was standard regs to have one.

 

[lorry108]

So one BG engineer says one thing and another say something else:
Here is wikis view on the subject:

http://www.diynot.com/wiki/electrics:main_equipotential_bonding[/QUOTE]

Thanks for the link Riveralt. I've read through it and I'm sorry to say I'm still non-the-wiser. I think it's quite simple though, if I can take up a little more of your time.

In your first comment you mentioned electrical cables. The British Gas engineer said that the earth bonding wire has a current which is why the gap applies to that as well - is that true or false? In a nutshell, my question is this: is it against the regs for an earth bonding wire to run along a gas pipe?

Thanks again in advance!

 

[1john]

I dont think there is anything in BS7671, the wiring regs what would prohibit a bonding cable being attached to a gas pipe. The gas regs however may say differently.

 

[lorry108]

I dont think there is anything in BS7671, the wiring regs what would prohibit a bonding cable being attached to a gas pipe. The gas regs however may say differently.

Does anyone know the answer from the gas regs perspective?

 

[Wontdothatagain]

I am meeting a Gas Safe Inspector this afternoon. I will ask the question and post back tonight.

 

[bernardgreen]

I am meeting a Gas Safe Inspector this afternoon. I will ask the question and post back tonight.

Ask him if there are any reports of meter readers standing on damp ground receive any tingles of electrical shock from gas meters. I noticed that the meter reader takes care not to touch our meter when he last read it. He took care to use a cloth to brush the debris from the glass over the digits.

I am thinking about the situation where the electrical earth derived from network supply neutral is not at true ground potential.

Also what effect would that have on any meters still fed by a metal gas supply pipe.