Bonding gas service ... or not!

[zap]

I'm working at a friend’s place and trying to keep costs down so here goes...

The gas meter is external and it feeds a boiler under the bungalow. (built on a hill).
The boiler ignition is fed via class II accessories and there is no prospect (I think) of an earth fault posing a threat.
There is no gas supply within the dwelling i.e. living areas.
The water supply is bonded to the met and tests satisfactory.

Does the gas service still require bonding? and if so, why.

Any help will be hugely appreciated.

 

[Engineer54]

Yes it does still need and require main bonding!! The gas service pipe is bringing an extraneous earth into the premises. It doesn't matter how much of an extraneous metal earth is exposed within an electrical installations equipotential Zone, it could be a just a few inches, it will still require main bonding!!

 

[Guitarist]

Is the boiler itself inside the bungalow in any way, shape or form?

 

[marcusone]

Yes it needs bonding. The bonding is required because of the earth potential the gas main may introduce. Nothing to do with earth faults. The gas boiler will be earthed, never met one that isn't.

 

[Guitarist]

I'm working at a friend’s place and trying to keep costs down so here goes...

If it wasn't a friends house, what would you do, just out of interest?

 

[zap]

In answer to your questions:
To access the boiler leave the rear of the building, down steps into the garden. The boiler is in a brick built coal scuttle. Well I think that's what it was. So although it's a part of the house, it's not accessible from within the living accommadation.

If this wasn't a friends house I would still be asking the question because I don't know the answer.

I don't understand how it's dangerous as it stands, what with the accessories being class II.

I've been asked to do what is necessary and if bonding is necessary, in this instance, I'll do it!

Thanks for all your advice but I wouldn't mind any reassurance.

 

[HandySparks]

Are the heating pipes from boiler to house copper or plastic?

 

[zap]

Are the heating pipes from boiler to house copper or plastic?

Copper water pipes which are bonded

 

[Guest111]

The gas main to the boiler will certainly be metal of one form or another regardless of the other pipes,and the boiler will have some form of earth so yes either way you look at it that gas needs bonding.

 

[Geordie Spark]

Yes it does still need and require main bonding!! The gas service pipe is bringing an extraneous earth into the premises. It doesn't matter how much of an extraneous metal earth is exposed within an electrical installations equipotential Zone, it could be a just a few inches, it will still require main bonding!!

If the Gas Service pipe buried in the ground is yellow Alkathene (plastic) and rises out of the ground encased in a glass fibre sleeve to a height of 18" above ground and is then joined to a steel service pipe which is connected via the Emergency Control Valve to the gas meter, what then?

Is it still "bringing an extraneous earth into the premises"?

I'm NOT trying to be smart here, I'm just asking a genuine question as I had "an issue" over this exact situation a while back. :smile5:

 

[Guest111]

If the Gas Service pipe buried in the ground is yellow Alkathene (plastic) and rises out of the ground encased in a glass fibre sleeve to a height of 18" above ground and is then joined to a steel service pipe which is connected via the Emergency Control Valve to the gas meter, what then?

Is it still "bringing an extraneous earth into the premises"?

I'm NOT trying to be smart here, I'm just asking a genuine question as I had "an issue" over this exact situation a while back. :smile5:

Now that is a good point,a lot of the new services are as you state,personally I would say not but it raises an interesting question,nice one Geordie.

 

[telectrix]

geordie, on this one. i'd |IR the metal part og the gas pipe to the MET. >22kOhms, then i'd consider it not to be extraneous.

 

[Engineer54]

If the Gas Service pipe buried in the ground is yellow Alkathene (plastic) and rises out of the ground encased in a glass fibre sleeve to a height of 18" above ground and is then joined to a steel service pipe which is connected via the Emergency Control Valve to the gas meter, what then?

Is it still "bringing an extraneous earth into the premises"?

I'm NOT trying to be smart here, I'm just asking a genuine question as I had "an issue" over this exact situation a while back. :smile5:

If the service is not bringing into the equipotential zone a potential source of earth, then NO the metallic service pipe after the control valve will not need main bonding. If that service pipe then disappears after the control valve under concrete and re-emerges elsewhere in the property then the chances are it ''Will'' need main bonding...

 

[Geordie Spark]

If the service is not bringing into the equipotential zone a potential source of earth, then NO the metallic service pipe after the control valve will not need main bonding. If that service pipe then disappears after the control valve under concrete and re-emerges elsewhere in the property then the chances are it ''Will'' need main bonding...

Thank you Eng54 :love:

In the case I quoted, i did the I R test thing on it & decided there was no need for a bond.

The next problem I had was convincing the "Gas Person" :dunce2: who arrived to commission the installation that it wasn't necessary ........

 

[zap]

geordie, on this one. i'd |IR the metal part og the gas pipe to the MET. >22kOhms, then i'd consider it not to be extraneous.

Tel, I've seen the limit of >22kOhms several times now but I haven't seen it in any publication. Can you elucidate, please?

Thanks for all your responses. I'll let my mate know that his gas service requires bonding.

 

[Geordie Spark]

geordie, on this one. i'd |IR the metal part og the gas pipe to the MET. >22kOhms, then i'd consider it not to be extraneous.

Thanks Tel.

That's what I did and found no need to bond, so didn't.

The really hard part was convincing the "Gas Person" and the customer (my mate as it happens) that there was no need, and I'm not sure if I succeeded there !!

 

[telectrix]

OK, you have a safe limit of 10mA through your body without the prospect of injury. so 230V/0.01A = 23kOhms. the reistannce of your body is 1K0hm, so there you get 22K.

 

[zap]

OK, you have a safe limit of 10mA through your body without the prospect of injury. so 230V/0.01A = 23kOhms. the reistannce of your body is 1K0hm, so there you get 22K.

Thanks for that Tel, it makes sense now.

 

[Guitarist]

Yet another long post lost to the ongoing problem. Thought it was sorted!

 

[Geordie Spark]

Yet another long post lost to the ongoing problem. Thought it was sorted!

Just when you thought it was safe to jump back into the water ........