Discuss Bonding of 2 gas pipes in the Electrical Forum area at ElectriciansForums.net

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Morning all, and happy Friday!

I feel I should know the answer to this one, but I'm not certain, even after consulting GN8.

A friend of mine has a semi-detached house with two copper gas pipes entering, one for the cooker and one for the boiler in the loft. They join together outside and are copper throughout. Currently there is no bonding to either of these, so obviously needs sorting. However, to get a bond to the cooker one will be difficult. Would you say both need bonding, or could he get away with just bonding the loft one?

He is looking to get an EICR done prior to selling, and wants to make sure everything is as OK as possible.

Cheers all.
 
The bond should be within 600mm of the gas meter or where it enters the building , however if its soldered copper gas pipe i would only code it as a C3 for bonding elsewhere.
 
The bond should be within 600mm of the gas meter or where it enters the building , however if its soldered copper gas pipe i would only code it as a C3 for bonding elsewhere.

That was also my line of thinking. If he bonds the loft pipe, then the lack of bond to the kitchen pipe would be C3 at worst.
 
You should be able to check the resistance between the two pipes (or more correctly between the bonded and non-bonded one) and if it is very low (e.g. the 0.05 ohms that comes up often) then you can say both are adequately bonded for electrical reasons.

Normally you want to bond before and T in the pipe, as joints for plumbing/gas reasons may not be good electrically speaking, especially for water where plastic push-fit is often substituted when any work is done. Could you bond outside before the pipe splits and run the cable in along side one of the pipes?
 
You should be able to check the resistance between the two pipes (or more correctly between the bonded and non-bonded one) and if it is very low (e.g. the 0.05 ohms that comes up often) then you can say both are adequately bonded for electrical reasons.

Normally you want to bond before and T in the pipe, as joints for plumbing/gas reasons may not be good electrically speaking, especially for water where plastic push-fit is often substituted when any work is done. Could you bond outside before the pipe splits and run the cable in along side one of the pipes?

Would be worth checking the resistance, although they are all well made copper joints so I expect it will be low.
 
Would be worth checking the resistance, although they are all well made copper joints so I expect it will be low.
They should be very low, but I have seen odd high electrical resistance on water pipe joints before. Gas ought to be better, but it is best to check just in case!
 
They should be very low, but I have seen odd high electrical resistance on water pipe joints before. Gas ought to be better, but it is best to check just in case!

Yes, that's a fair comment.
 
This may not be directly relevant to the the EICR, but my (limited!) experience is that a gas engineer would expect to see the bonding within 60cm of the meter, and importantly before any branch in the pipe (which in this case appears to be external to the building). I have also heard of smart meter fitters refusing to fit a meter if the above is not met. Admittedly this appears to be due to "guidance" rather than "regulation" - I don't want to get into that - but it may cause issues, maybe from inspection by someone who is more gas biased!

From the gas perspective: Technical Bulletin 102 - https://registeredgasengineer.co.uk/technical/technical-bulletin-102-2/
 
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This may not be directly relevant to the the EICR, but my (limited!) experience is that a gas engineer would expect to see the bonding within 60cm of the meter, and most importantly before any branch in the pipe (which in this case appears to be external to the building)

Yes, and this situation with the external tee makes it a bit less straightforward. Although the gas work was done by a corgi installer.
 
2 sites i have visited in the last week'

1. external gas meter, pipe then goes 10ft up external, 12 ft. horizontal external, then enters building above 1st floor ceiling. gas monkeys have run a 10mm bonding from CU, out with the gas pipe, draped across outside wall, not a clip in sight, to the meter box, "coz that's where it has to go, according to gas regs".

2. EICR..... CU in small cupboard, terraced house. can't get the cover off as gas monkey has run a 22mm gas pipe directly in front of and touching the CU cover.
 
as stated previously, the Gas pipe should be bonded as close to the consumer side of the gas meter as possible or within 600mm if external. Reg:544.1.2.
Napit Codebreakers state if there is no main protective bonding conductors to the installation pipes (water, gas, oil) it is a C2 and FI referring to Reg: 411.3,1.2
 
You should be able to check the resistance between the two pipes (or more correctly between the bonded and non-bonded one) and if it is very low (e.g. the 0.05 ohms that comes up often) then you can say both are adequately bonded for electrical reasons.

Normally you want to bond before and T in the pipe, as joints for plumbing/gas reasons may not be good electrically speaking, especially for water where plastic push-fit is often substituted when any work is done. Could you bond outside before the pipe splits and run the cable in along side one of the pipes?
Completely agree PC1966, but just to play devils advocate... 2 separate metal pipes joined by a very small length of 1mm conductor could test as 0.05 ohms. Touching pipes may test very low as well. I know it's a silly example, but just interested in what you will say.
 
Completely agree PC1966, but just to play devils advocate... 2 separate metal pipes joined by a very small length of 1mm conductor could test as 0.05 ohms. Touching pipes may test very low as well. I know it's a silly example, but just interested in what you will say.
It is perfectly true that you can have a low resistance joint that will fail in time or at high current, so such a test is not proof of a good electrical bond. Conversely, if the test fails you know the bond is bad!

The older mains-powered PAT testers could do a bond check at currents as high as 15-30A to weed out bonds hanging on by a thin strand, but few meters still offer that brutal check method.
 
Out of curiosity, have you checked that the incoming gas pipe is copper?

It is perfectly true that you can have a low resistance joint that will fail in time or at high current, so such a test is not proof of a good electrical bond. Conversely, if the test fails you know the bond is bad!

The older mains-powered PAT testers could do a bond check at currents as high as 15-30A to weed out bonds hanging on by a thin strand, but few meters still offer that brutal check method.

A very useful test.
 
Completely agree PC1966, but just to play devils advocate... 2 separate metal pipes joined by a very small length of 1mm conductor could test as 0.05 ohms. I know it's a silly example, but
Not silly at all. You have simply exposed what can be a very real vulnerability in any electrical conductor (not just a bonding conductor). This is where the often underestimated "visual test" comes in to its own. And the electrical reality is that our meters and testers have their limitations.
 

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