Gas bonding after the first T joint

[ipk300]

Hi,

I have read that the gas bonding needs to be within 600mm of the outlet of the gas meter and before the first T joint. My question is, what can happen if the bonding is after the first T joint? If there was a fault would the earth fault go and liven the the gas meter and incoming gas pipe, and is that the reason for it to be before the first T joint?

Thank you for any reply's.

 

[EFLImpudence]

I have read that the gas bonding needs to be within 600mm of the outlet of the gas meter and before the first T joint.

That is what the regulation does indeed state.

My question is, what can happen if the bonding is after the first T joint?

Nothing different.

If there was a fault would the earth fault go and liven the the gas meter and incoming gas pipe,

It could do that anyway.

and is that the reason for it to be before the first T joint?

Not really. There is no reason.
Anywhere would have the same effect.
If the gas meter had an insulator separating the inlet pipe from the outlet pipe the bond would be totally ineffective.

The reason for it to be on the outlet side is a flaw in itself. The actual pipe which needs bonding is the inlet pipe where it enters the property. I have always assumed that this is not the requirement because the Gas Companies do not want it on their pipework - or
Whoever wrote the regulation did not understand bonding.
I may be wrong - about the reason not the facts.

It is the pipe which enters the premises which needs bonding (joining) to the Main Earth Terminal of the electrical installation to equalise any potential difference between them in the event of a fault.
It is not like earthing metal parts to ensure the protective device opens to disconnect the supply.

 

[PrenticeBoyofDerry]

The reason why the gas pipe requires bonding before the first branch/tee, is in case that branch is ever removed and the branch removed is where the pipe is bonded.

 

[bernardgreen]

what can happen if the bonding is after the first T joint?

From a Fire Investigation Officer many year ago

the concern was about faults that created high fault currents in the bonded gas pipes. If this high current passed over a soldered joint then there was a small risk of the solder melting and gas escaping.

.

This was when steel / iron gas mains were still in use and very high fault currents along gas pipes were possible. I personally doubt even a very badly soldered joint on a gas pipe could get hot enough to soften the solder enough for the joint to fail.

 

[Jackrae]

what can happen if the bonding is after the first T joint?

From a Fire Investigation Officer many year ago

the concern was about faults that created high fault currents in the bonded gas pipes. If this high current passed over a soldered joint then there was a small risk of the solder melting and gas escaping.

.

That's probably the reason why we never use solder to make electrical joints

 

[PrenticeBoyofDerry]

Can hardly be anything to do with soldered joints, as the regulations do not require the bonding to be made before any soldered joints. The gas union is often solder on to the copper distribution gas pipe and that is before any tees/branch pipes.
And not all tees/branches are soldered joints, they can be compression joints!

 

[bernardgreen]

Can hardly be anything to do with soldered joints,

I agree, I posted the FIO's comment as an indication of some of the thinking that may have gone into the process of writing the book of rules.

 

[ban-all-sheds]

But it isn't really thinking, is it.

 

[Jackrae]

Maybe a case of "If I can't find a reason I'll make one up, after all who's going to argue, I'm a 'professional'"