Bonding of 2 gas pipes

[DPG]

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.

 

[newfutile]

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.

 

[DPG]

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.

 

[pc1966]

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?

 

[Rockingit]

To my mind, bond the one that's easiest and check continuity from there to the other.

 

[DPG]

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.

 

[pc1966]

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!

 

[DPG]

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.

 

[Avo Mk8]

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/

 

[DPG]

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.

 

[Avo Mk8]

Yes, and this situation with the external tee makes it a bit less straightforward. Although the gas work was done by a corgi installer.

I had mine done by a registered gas installer, but he still left me with non-compliant bonding according to the smart meter installer?

 

[LastManOnline]

Yes, and this situation with the external tee makes it a bit less straightforward.

Out of curiosity, have you checked that the incoming gas pipe is copper?

 

[telectrix]

Out of curiosity, have you checked that the incoming gas pipe is copper?

it's usually steel.

 

[telectrix]

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.

 

[TykeSpark]

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

 

[HappyHippyDad]

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.

 

[pc1966]

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.

 

[DPG]

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.

 

[LastManOnline]

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.

 

[LastManOnline]

it's usually steel.

Of course. I should have said "metallic". But my point was to highlight that the incomer may be "plastic" and not require main bonding

 

[7029 dave]

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.

Your eyes tell you quite a lot, in some situations still like to use my analogue meters like to see a moving needle.

 

[loz2754]

A very useful test.

But most definitely not for use on a GAS pipe, surely!

 

[telectrix]

But most definitely not for use on a GAS pipe, surely!

just need to have applied a match to the joint first. ... make sure it no leak .

 

[loz2754]

Ah, so that's what a test match is!

 

[telectrix]

Ah, so that's what a test match is!

eggsackly.

 

[Doomed]

Back when I was a student called the gas board in because of a smell of gas (which the landlord denied and said he had it checked).
He really did light a lighter and ran along the pipe until he got a little gout of flame from a tiny tiny hole.
He then condemed every gas appliance in the house (much to the landlords annoyance)

 

[telectrix]

we had a leak , BG capped off the tee into the house ( hob and unused gas fire just leaving feed to boiler in garage, don under maintenance plan so no charge. ). my mate the plumber then tapped off the the boiler feed to re-feed the hob, that cost me 3 pints of ale. winner.

 

[DefyG]

a gas engineer would expect to see the bonding within 60cm of the meter

Looked at a job recently where a gas engineer had advised the above as a 'non compliance'.
The meter is external to the property (small block of flats) but incoming gas service pipe (copper) to the flat (second floor) has been bonded within 600mm of entering the flat. (Not easy route from internal service cupboard to ground floor meter!).
There doesn't seem to be a 3 tier system like the EICR to determine compliance (saftey) with the gas report but I advised the landlord from an electrical pov, it would be C3 at worst which is declared 'Satisfactory'!
(The recent EICR was just ticked!) The LL will take up the issue with the gas engineer/company.
Agree?

 

[Intoelectrics]

Looked at a job recently where a gas engineer had advised the above as a 'non compliance'.
The meter is external to the property (small block of flats) but incoming gas service pipe (copper) to the flat (second floor) has been bonded within 600mm of entering the flat. (Not easy route from internal service cupboard to ground floor meter!).
There doesn't seem to be a 3 tier system like the EICR to determine compliance (saftey) with the gas report but I advised the landlord from an electrical pov, it would be C3 at worst which is declared 'Satisfactory'!
(The recent EICR was just ticked!) The LL will take up the issue with the gas engineer/company.
Agree?

Something that bugs me is that the bond is an "electrical" safety requirement. So if the electrician deems the bonding to be compliant with the current regs, why do the gas monkeys and meter readers think they can override this?