Earthing the gas supply pipe into the house

[JohnW2]

actually.. just a though.. are their pipes thjat don't need earthing? The copper pipe is only 8 feet long.. could I get the pipe replaced?

Assuming that you're talking about pipework within the building, plastic gas pipes (which are usually the only ones which would not require main bonding) are not allowed in residential properties.

Kind Regards, John

 

[JohnW2]

Extraneous-conductive-parts require bonding because they are earthed.

I know you often assert that, but I would sugfgest that it would be strictly more true to say "... because they are earthed OR could become earthed". Don't forget that the regs define an 'extraneous-conductive part' (which requires main bonding) as a conductor which is "liable to introduce a potential (usually earth potential)" - not necessarily one that is 'introducing earth potential' (i.e. has a lowish resistance/impedance to earth) when you happen to test it.

In the OP's case, if the meter in an external enclosure is supplied by plastic pipe, and if the (metal pipe) feed from the meter to the house doesn't go anywhere near the ground, might it not be argued that the pipe entering the house was not an extraneous-c-p, and therefore didn't need main bonding?

Kind Regards, John

 

[EFLImpudence]

Extraneous-conductive-parts require bonding because they are earthed.

I know you often assert that, but I would suggest that it would be strictly more true to say "... because they are earthed OR could become earthed".

Mmmm. Are you sure?

Don't forget that the regs define an 'extraneous-conductive part' (which requires main bonding) as a conductor which is "liable to introduce a potential (usually earth potential)" - not necessarily one that is 'introducing earth potential'

Is that not because there may be extraneous parts which do not introduce a potential (should that be a potential difference?) rather than may be extraneous tomorrow but not today.

If not, how would you test for that?
Is it 23,001Ω (ignore body) or is it a judgement call resulting in bonding isolated parts?

(i.e. has a lowish resistance/impedance to earth) when you happen to test it.

Is a lowish resistance/impedance to earth not earthed?

In the OP's case, if the meter in an external enclosure is supplied by plastic pipe, and if the (metal pipe) feed from the meter to the house doesn't go anywhere near the ground, might it not be argued that the pipe entering the house was not an extraneous-c-p, and therefore didn't need main bonding?

Yes - more a statement than argument.
Would that be because it is not earthed?
I don't understand why you have asked this.

 

[JohnW2]

I know you often assert that, but I would suggest that it would be strictly more true to say "... because they are earthed OR could become earthed".

Mmmm. Are you sure?

Well, I'm pretty sure that it is closer to the regs' definition of an extraneous-c-p than your version. To say that something is "liable to do" something is not the same as saying that it is already doing that something. (e.g. "this road is liable to subsidence").

Don't forget that the regs define an 'extraneous-conductive part' (which requires main bonding) as a conductor which is "liable to introduce a potential (usually earth potential)" - not necessarily one that is 'introducing earth potential'

Is that not because there may be extraneous parts which do not introduce a potential (should that be a potential difference?) rather than may be extraneous tomorrow but not today.

I'm not sure I understand that, because if it is deemed that something cannot introduce a potential (by definition, a pd relative to something - there is no such thing as absolute potential), then it cannot be an extraneous-c-p. However, as above, if it is 'liable to introduce a potential', that does not necessarily mean that it always will introduce a potential.

If not, how would you test for that? Is it 23,001Ω (ignore body) or is it a judgement call resulting in bonding isolated parts?

That's why I worry a little about your reliance on 'testing'. In one direction, it's fine - if you measure and get <23,001&#937;, then you have demonstrated the 'liability to introduce earth potential' - so it's an extraneous-c-p that needs main bonding. However, if your measurement is >23,000&#937; (maybe much greater than 23,000&#937 then, indeed, I think it's a "judgement call". If, for example, it was a short length of oil pipe emerging out of the soil or gravel, and your measurement during a lengthy very hot and dry spell resulted in a measured resistance to earth considerably greater than 23,000&#937;, I would expect and hope that your judgement would be that it was nevertheless 'liable to introduce a potential' (under different weather conditions), and hence was an extraneous-c-p that needed to be main bonded.

In the OP's case, if the meter in an external enclosure is supplied by plastic pipe, and if the (metal pipe) feed from the meter to the house doesn't go anywhere near the ground, might it not be argued that the pipe entering the house was not an extraneous-c-p, and therefore didn't need main bonding?

Yes - more a statement than argument. Would that be because it is not earthed?
I don't understand why you have asked this.

As above, I would say that it would be because it was not 'earthed' (<23,000&#937 when you inspected it and also because your judgement was (because it was well away from the ground) that it was not 'liable to' become earthed due to prevailing conditions in the future.

Kind Regards, John

 

[EFLImpudence]

I know you often assert that, but I would suggest that it would be strictly more true to say "... because they are earthed OR could become earthed".

Mmmm. Are you sure?

Well, I'm pretty sure that it is closer to the regs' definition of an extraneous-c-p than your version. To say that something is "liable to do" something is not the same as saying that it is already doing that something. (e.g. "this road is liable to subsidence").

Yes, but I am sure it is "liable to introduce a potential" and not "liable to become extraneous".

Don't forget that the regs define an 'extraneous-conductive part' (which requires main bonding) as a conductor which is "liable to introduce a potential (usually earth potential)" - not necessarily one that is 'introducing earth potential'

Is that not because there may be extraneous parts which do not introduce a potential (should that be a potential difference?) rather than may be extraneous tomorrow but not today.

I'm not sure I understand that, because if it is deemed that something cannot introduce a potential (by definition, a pd relative to something - there is no such thing as absolute potential), then it cannot be an extraneous-c-p. However, as above, if it is 'liable to introduce a potential', that does not necessarily mean that it always will introduce a potential.

Isn't that what I said?
It was you who said that parts which are (deemed) NOT extraneous may be at a later date.

How have you determined that the above example is NOT extraneous?

The definition also relates to supplementary bonding where the potential may not be earth potential.

If not, how would you test for that? Is it 23,001&#937; (ignore body) or is it a judgement call resulting in bonding isolated parts?

That's why I worry a little about your reliance on 'testing'. In one direction, it's fine - if you measure and get <23,001&#937;, then you have demonstrated the 'liability to introduce earth potential' - so it's an extraneous-c-p that needs main bonding. However, if your measurement is >23,000&#937; (maybe much greater than 23,000&#937 then, indeed, I think it's a "judgement call". If, for example, it was a short length of oil pipe emerging out of the soil or gravel, and your measurement during a lengthy very hot and dry spell resulted in a measured resistance to earth considerably greater than 23,000&#937;, I would expect and hope that your judgement would be that it was nevertheless 'liable to introduce a potential' (under different weather conditions), and hence was an extraneous-c-p that needed to be main bonded.

Doesn't the fact that it is in the ground render it extraneous without testing?
I would not consider that a judgement call; it would be obvious.

I merely asked about the 23,000 because you indicated that parts which were deemed NOT extraneous may be at a later date.

Put another way, you have an isolated part (i.e. totally apart) so how can it become extraneous.

In the OP's case, if the meter in an external enclosure is supplied by plastic pipe, and if the (metal pipe) feed from the meter to the house doesn't go anywhere near the ground, might it not be argued that the pipe entering the house was not an extraneous-c-p, and therefore didn't need main bonding?

Yes - more a statement than argument. Would that be because it is not earthed?
I don't understand why you have asked this.

As above, I would say that it would be because it was not 'earthed' (<23,000&#937 when you inspected it and also because your judgement was (because it was well away from the ground) that it was not 'liable to' become earthed due to prevailing conditions in the future.

How can it? It would be hundreds of Mega ohms. I still don't understand the point you are making.

 

[JohnW2]

Yes, but I am sure it is "liable to introduce a potential" and not "liable to become extraneous".

I'm not sure what, in that context, you mean by "extraneous" - are you using it as shorthand for "extraneous-c-p"? "Extraneous", alone, is not defined in the regs. What is defined is "extraneous-conductive-part" and, as you know, that is defined as something which is "liable to introduce a potential". So, as far as the regs are concerned, "liable to introduce a potential" and "extraneous-c-p" are the same thing ... so I don't really understand your comment above.

However, as above, if it is 'liable to introduce a potential', that does not necessarily mean that it always will introduce a potential.

Isn't that what I said? It was you who said that parts which are (deemed) NOT extraneous may be at a later date.

You still do not seem to have grasped my understanding of the significance of the words "liable to". To me (just as with the road which is "liable to" subsidence) "liable to" refers to the existence of a possibility of something which may happen in the future. Hence, if my judgement is that the conductor may (e.g. because of its routing) 'introduce a potential in the future' then I believe that it already is an extraneous-c-p, per reg definitions (because of that 'liability to introduce a potential'), even though, at the time you see it, the resistance/impedance to earth might be extremely high. .

Doesn't the fact that it is in the ground render it extraneous without testing? ... I would not consider that a judgement call; it would be obvious.

That is exactly my (one and only) point, whether you call it 'obvious' or a 'judgement call'. My concern is that people reading what you often write (about 'testing') could easily take you to be saying that if they measured a resistance of >23,000&#937; to earth, it would not count as an extraneous-c-p even if it was emerging from the ground.

As I said, <23,000&#937; (or whatever) is meaningful (definitely indicates an extraneous-c-p), but >23,000&#937; means that one has to look at the situation to see whether, despite the high measurement (it could even be countless M&#937; on a particularly good/bad day), it is "obviously" (or, at least, probably/ potentially) an extraneous-c-p. One clearly cannot take a hight resistance to earth (at the time of measurement) to indicate that something is not an extraneous-c-p - as you've said it might 'obviously' be an extraneous-c-p, no matter how high the measured resistance to earth on a particular occasion.

I still don't understand the point you are making.

Does the above help at all? As I've said, I think we agree about the actual issues, my point being that what you often write about 'testing' is possibly at risk of being misinterpreted by those who do not already understand.

Kind Regards, John

 

[EFLImpudence]

Yes, but I am sure it is "liable to introduce a potential" and not "liable to become extraneous".

I'm not sure what, in that context, you mean by "extraneous" - are you using it as shorthand for "extraneous-c-p"? "Extraneous", alone, is not defined in the regs. What is defined is "extraneous-conductive-part" and, as you know, that is defined as something which is "liable to introduce a potential". So, as far as the regs are concerned, "liable to introduce a potential" and "extraneous-c-p" are the same thing ... so I don't really understand your comment above.

Of course I am meaning "extraneous-c-p".
As per the definitions -
Extraneous-conductive-part. A conductive part liable to introduce a potential,...
Therefore does it not follow that a conductive-part may be extraneous (of external origin)?

I am saying that the 'liable' refers to 'introducing potential' and not (although the outcome is the same) as you are implying that parts are liable to become e-c-ps even though they have been determined as not.

However, as above, if it is 'liable to introduce a potential', that does not necessarily mean that it always will introduce a potential.

Isn't that what I said? It was you who said that parts which are (deemed) NOT extraneous may be at a later date.

You still do not seem to have grasped my understanding of the significance of the words "liable to". To me (just as with the road which is "liable to" subsidence) "liable to" refers to the existence of a possibility of something which may happen in the future. Hence, if my judgement is that the conductor may (e.g. because of its routing) 'introduce a potential in the future' then I believe that it already is an extraneous-c-p, per reg definitions (because of that 'liability to introduce a potential'), even though, at the time you see it, the resistance/impedance to earth might be extremely high. .

I understand all that but you still have not explained how you will determine that a c-p which has been classed as NOT an e-c-p may become one.

Doesn't the fact that it is in the ground render it extraneous without testing? ... I would not consider that a judgement call; it would be obvious.

That is exactly my (one and only) point, whether you call it 'obvious' or a 'judgement call'. My concern is that people reading what you often write (about 'testing') could easily take you to be saying that if they measured a resistance of >23,000&#937; to earth, it would not count as an extraneous-c-p even if it was emerging from the ground.

As I said, <23,000&#937; (or whatever) is meaningful (definitely indicates an extraneous-c-p), but >23,000&#937; means that one has to look at the situation to see whether, despite the high measurement (it could even be countless M&#937; on a particularly good/bad day), it is "obviously" (or, at least, probably/ potentially) an extraneous-c-p. One clearly cannot take a hight resistance to earth (at the time of measurement) to indicate that something is not an extraneous-c-p - as you've said it might 'obviously' be an extraneous-c-p, no matter how high the measured resistance to earth on a particular occasion.

You say that now but ONE of your points was that a gas supply which is clearly NOT an e-c-p may become one.

I only introduced the 23,000 wondering about which method you choose for determining which parts may become e-c-ps tomorrow.
I know that you are saying that it is therefore an e-c-p today but you have described a situation which clearly is not.
I don't think I have ever suggested doing that to a pipe which emerges from the ground. It is obviously an e-c-p.

I still don't understand the point you are making.

Does the above help at all? As I've said, I think we agree about the actual issues, my point being that what you often write about 'testing' is possibly at risk of being misinterpreted by those who do not already understand.

Not really.
We may agree about the actual issues but not your introduced non e-c-p supply pipe which may change.


My statement that parts require bonding because they are earthed is true.
I think it is a good explanation of the difference to people who do not understand the situation.
(I have never said that parts do not require bonding because they are not earthed.)
I feel you are being disingenuous by linking this true statement with ways of testing for this and raising odd examples of parts which are not e-c-ps by any definition or test but which may (impossibly) become one an so are.

 

[JohnW2]

I am saying that the 'liable' refers to 'introducing potential' and not (although the outcome is the same) as you are implying that parts are liable to become e-c-ps even though they have been determined as not.

I still don't really understand, assuming you are working to the BS7671 definition. As far as BS7671 is concerned, a conductor which is considered "liable to introduce a potential" (now, or in the future) is, and always will be, an extraneous-c-p. A conductor which is not considered "liable to introduce a potential (now or in the future) is not, and never will be, an extraneous-c-p. Only if circumstances were to change (e.g. a previously above-ground pipe were buried, or vice versa), could something 'become' (or 'unbecome') an extraneous-c-p.

I understand all that but you still have not explained how you will determine that a c-p which has been classed as NOT an e-c-p may become one.

As above, I do not believe that something can become (or 'unbecome') and extraneous-c-p unless the circumstances of the conductor change.

You say that now but ONE of your points was that a gas supply which is clearly NOT an e-c-p may become one.

When/where did I say that? As above, I do not believe that a conductor can change it's e-c-p status (yes/no) unless the circumstances of the conductor change (e.g. re-routing).

I don't think I have ever suggested doing that to a pipe which emerges from the ground. It is obviously an e-c-p.

You haven't ever suggested that - but, as I said, those who do not understand could perhaps (mis)interpret your comments about testing as implying that.

Not really. We may agree about the actual issues but not your introduced non e-c-p supply pipe which may change.

Again I am confused. As above, I do not believe that the e-c-p status (yes/no) of a conductor can change unless the circumstances of that conductor change (e.g. re-routing).

My statement that parts require bonding because they are earthed is true. I think it is a good explanation of the difference to people who do not understand the situation. (I have never said that parts do not require bonding because they are not earthed.)

I suppose that is the crux of my point - that perhaps you should explicitly qualify your statements with that latter bit - i.e. that not being earthed (e.g. >23k&#937; to earth) does not necessarily mean that bonding is not required.

Kind Regards, John

 

[EFLImpudence]

When/where did I say that? As above, I do not believe that a conductor can change it's e-c-p status (yes/no) unless the circumstances of the conductor change (e.g. re-routing).

I thought that was what you meany when you wrote:

Extraneous-conductive-parts require bonding because they are earthed.

I know you often assert that, but I would sugfgest that it would be strictly more true to say "... because they are earthed OR could become earthed". Don't forget that the regs define an 'extraneous-conductive part' (which requires main bonding) as a conductor which is "liable to introduce a potential (usually earth potential)" - not necessarily one that is 'introducing earth potential' (i.e. has a lowish resistance/impedance to earth) when you happen to test it.

In the OP's case, if the meter in an external enclosure is supplied by plastic pipe, and if the (metal pipe) feed from the meter to the house doesn't go anywhere near the ground, might it not be argued that the pipe entering the house was not an extraneous-c-p, and therefore didn't need main bonding?

If not, why did you ask it?

I don't think I have ever suggested doing that to a pipe which emerges from the ground. It is obviously an e-c-p.

You haven't ever suggested that - but, as I said, those who do not understand could perhaps (mis)interpret your comments about testing as implying that.

But that is the accepted way of testing for an e-c-p.
I do not nor would not suggest that method of testing for a pipe which emerges from the ground.

My statement that parts require bonding because they are earthed is true. I think it is a good explanation of the difference to people who do not understand the situation. (I have never said that parts do not require bonding because they are not earthed.)

I suppose that is the crux of my point - that perhaps you should explicitly qualify your statements with that latter bit - i.e. that not being earthed (e.g. >23k&#937; to earth) does not necessarily mean that bonding is not required.

My statement that parts require bonding because they are earthed does not need qualifying.
It is given to help people understand the difference between earthing and bonding.

It is patently no help in determining which parts require bonding, is it?

 

[JohnW2]

I thought that was what you meany when you wrote:

In the OP's case, if the meter in an external enclosure is supplied by plastic pipe, and if the (metal pipe) feed from the meter to the house doesn't go anywhere near the ground, might it not be argued that the pipe entering the house was not an extraneous-c-p, and therefore didn't need main bonding?

If not, why did you ask it?

I suppose I probably made it sound much more like a 'real question' than I really intended. The point in my mind was that some people appear not to agree with us and, because of 'wet walls', 'meter cabinets filling up with water' or whatever feel that any conductor entering a building from 'outside' should be considered to be an extraneous-c-p, even if it goes nowhere near the ground.

My statement that parts require bonding because they are earthed does not need qualifying.

Maybe I'm wrong but my fear is that, without qualification, some people may (incorrectly) read into it the corollary - i.e. that parts which are not earthed do not ('ever') need bonding.

It is given to help people understand the difference between earthing and bonding.

Fair enough - but might it not help them even more if you also explained that parts which are not (currently) earthed may nevertheless need bonding?

Kind Regards, John

 

[Coaster]

Hello.
Do you have an external electric meter box near your gas meter box ?
Regards
Ed

Nope, it's inside the hallway about 30 feet away.. and about 4 inches from the MET ironically..

I'll fit the wire to bond the gas if needs be, just checking if I could save the hassle fitting it as the route between the gas pipe and MET is bloody tricky.
I'm planning a route now as I type lol

 

[Coaster]

will be doing the job when i get the time

 

[IJWS15]

actually.. just a though.. are their pipes thjat don't need earthing?
The copper pipe is only 8 feet long.. could I get the pipe replaced?

You could replace with iron (or a gas safe fitter could) but that would still need bonding.

AFAIK you cannot use plastic for gas in a building - think about what happens in a fire.

 

[Coaster]

Hello.
Do you have an external electric meter box near your gas meter box ?
Regards
Ed

nope, the electric meter and the MET is about 30 feet away.
looks like a the wiring needs to installed then if I have to have a copper pipe?

 

[EFLImpudence]

Coaster: Is there by chance a water pipe near (or more accessible to) the gas entry point.

It is permitted to use a water pipe as the bonding conductor for the gas pipe (but not vice versa).
So if you could connect the gas pipe to a nearby water pipe and verify its continuity, that would be satisfactory.