Gas supply earth bonding

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Richard Bourne

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Having a new house built where gas meter box is some 10 metres away from consumer unit, but next to electric meter box which feeds consumer unit by sub main.

I understand gas supply needs earth bonding within 600mm of incoming supply, does earth bonding need to be run back to the consumer unit, or can it be bonded to the earth block in the electric box? Also would it be 6mm or 10mm earthing cable?

grateful fir advice.
 
Not quite.

IF the gas pipe is an extraneous-conductive-part then it should be bonded at the point of entry to the premises 'where practicable'.
The bonding conductor should be run to the main earthing terminal - presumably the block in the electric box.

Edit - 10mm².
 
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crystal ball said:
New build - will it be plastic pipe?
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The supply pipe may well be plastic, but what matters is what enters the house, and what route it takes. As I understand it, plastic gas pipe is not allowed to enter domestic properties.

If the supply feed is plastic, and the metal pipe which enters the house (from the meter, if meter is external) 'keeps well away from the ground', then it probably does not qualify as an extraneous-c-p, and therefore would not need bonding.

Kind Regards, John
 
Apparently this is where gas and electric differ, I've heard stories of electricians not bonding new builds after testing whether the gas is extraneous or not and been told to come back and do it before getting paid.

But yes, it can be connected to the main earthing terminal wherever that is. If the gas is the only part that needs bonding then just declare the terminal in the meter box as the main earthing terminal. The one in the consumer unit is just for convenience
 
I've heard stories where plumbers won't commission boilers without what they call cross bonding.

That don't make it right.
 
EFLImpudence said:
I've heard stories where plumbers won't commission boilers without what they call cross bonding.

That don't make it right.
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It's happened to me when I had a new boiler installed. I explained to the installation engineers why it was unnecessary - especially with a Worcester-Bosch where all the pipes are connected together by the wall mounted manifold, but they said "We have to do it because our company electrician has said we must."! :(
 
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AndyPRK said:
As I have said before, incomming gas bonding is part of the gas safe checklist (when renting out a house), so the gas people want it!
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The question on that form appears to be ...

"Is the main protective equipotential bonding satisfactory?"

One might hope that someone who understood and knew what they were doing would understand that it was "satisfactory" for bonding to be absent if/when there was no electrical reason for it being present!

Kind Regards, John
 
Pretty pointless question, that's like asking me a question about laminar flow in gas pipelines. If you ask someone a question they are not qualified to answer you need some kind of certification from the electrician to say it's satisfactory.
 
John D v2.0 said:
Pretty pointless question, that's like asking me a question about laminar flow in gas pipelines. If you ask someone a question they are not qualified to answer you need some kind of certification from the electrician to say it's satisfactory.
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Quite so.

A question of the form "Is bonding present?" would be straightforward enough for a non-electrician to answer, but would fail for at least two reasons - firstly, 'being present' is theoretically no proof that it is 'satisfactory' and secondly, more on-topic, such a question would not address the issue of whether or not bonding was actually required (electrically speaking).

However, unless the GasSafe folk are adequately trained and equipped, it's hard to see how this aspect of a GasSafe inspection could be satisfactorily undertaken without involvement of an electrician (which would not really be practical).

I suppose the real question is whether the issue of bonding should be part of a GasSafe inspection at all. I would say that it is an issue of electrical safety, and I struggle to see that it has any bearing on any aspects of gas safety. On the contrary, if one wants to scrape the barrel for theoretical issues, bonding a gas pipe could, under certain fault scenarios, lead to high electrical currents flowing through gas pipes - which I suspect would not be regarded as a good thing by gas folk!

Kind Regards, John
 
I guess if we really want to get into it, there is probably more overall danger withfrom installations missing bonding that need it, than the cost of bonding unnecessary (most will be effectively bonded via the boiler)
So the question is probably alright and better than just not mentioning it, in the minds of those who added it.
 
John D v2.0 said:
I guess if we really want to get into it, there is probably more overall danger withfrom installations missing bonding that need it, than the cost of bonding unnecessary (most will be effectively bonded via the boiler)
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Agreed, in electrical terms.

As you say, in practice it is all-but-inevitable (at least, if there is a boiler) that gas pipework will be 'incidentally' connected to earth, so 'unnecessarily bonding' will rarely do any harm. However, that incidental bonding is not totally inevitable (see ***) - and, if such does not exist, then 'unnecessarily bonding' results in an unnecessary increase in the risk of electric shock within the building.

[*** I don't know if (m)any such houses still exist, but my parents lived in a house with gas 'fires' and gas cookers (and, at one point, even a gas fridge), but no boiler - hence no electrical continuity between gas pipes and anything electrical (or the water plumbing). I doubt that there was any incidental path to earth from any of that ]

John D v2.0 said:
So the question is probably alright and better than just not mentioning it, in the minds of those who added it.
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As above, it is an electrical issue, so should there be any question about it at all? As has been said, there seems to be little point in asking such questions of someone who is not necessarily knowledgeable enough to judge whether bonding is satisfactory or even (electrically) required.

Kind Regards, John
 
JohnW2 said:
I suppose the real question is whether the issue of bonding should be part of a GasSafe inspection at all. I would say that it is an issue of electrical safety, and I struggle to see that it has any bearing on any aspects of gas safety. On the contrary, if one wants to scrape the barrel for theoretical issues, bonding a gas pipe could, under certain fault scenarios, lead to high electrical currents flowing through gas pipes - which I suspect would not be regarded as a good thing by gas folk!
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Yes - especially as the regulations, for some reason, require the bonding to be connected in the wrong place; i.e. on the consumer's side.

Nothing to do with a gas inspection, but were a meter fitter to disconnect the meter without himself bridging the intended separation between the consumer's side and the incoming pipe, then the bonding on the consumer's side would be rendered ineffective.
 
JohnW2 said:
I suppose the real question is whether the issue of bonding should be part of a GasSafe inspection at all. I would say that it is an issue of electrical safety, and I struggle to see that it has any bearing on any aspects of gas safety.
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JohnW2 said:
As has been said, there seems to be little point in asking such questions of someone who is not necessarily knowledgeable enough to judge whether bonding is satisfactory or even (electrically) required.
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Maybe an EICR form should contain the question "Is the gas pipework satisfactory?" :-)

Kind Regards, John
 
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