Main bonding diagram (2)

[JohnW2]

I don't see how it could be fitted that close.

Well, I did only say 'extremely close'. However, I can't see why anyone would do that - if the water supply pipe were plastic, it would make sense to bring it right into the building (as far as the meter, stopcock or whatever). I don't think that the issue really arises with gas pipes since, to the best of my knowledge 'insulating (presumably plastic) sections' would not be allowed anywhere within the building.

Kind Regards, John

 

[EFLImpudence]

I don't think that the issue really arises with gas pipes since, to the best of my knowledge 'insulating (presumably plastic) sections' would not be allowed anywhere within the building.

The regulation applies to gas meters (which is why I cannot agree with your interpretation).
http://electrical.theiet.org/wiring-matters/61/gas-pipes/index.cfm

 

[JohnW2]

The regulation applies to gas meters (which is why I cannot agree with your interpretation). http://electrical.theiet.org/wiring-matters/61/gas-pipes/index.cfm

I was talking about gas pipes, not meters, and was observing that, to the best of my knowledge, insulating (presumably plastic) sections were not allowed in gas pipes within buildings (certainly domestic ones), such that the bit in the regs about 'insulation sections' presumably could not apply to gas pipes. However, I'm a bit confused by the article you linked to, since it seems to be saying that they are 'required'. Having said that, I can't quite work out whether they are installed outside or inside the building ....

Insulation fittings shall be installed in accessible location as close to the pipes entry into the building or, in the case of external pipework, as close as possible to the pipes exit to the ground and upstream of any ECV. The uninsulated section of the exposed pipe shall be as short as possible.

How would you interpret that?

Whatever, although, as above, I doubt whether the 'insulating section' bit of the reg can apply to gas pipes, the "or when there is a meter" bit certainly can, and that is where the reg's potential 'silliness' can arise (IF there is an 'insulating joint' and/or IF there is no electrical continuity through the gas meter - in either of which cases the regs would require one to bond something which wasn't an extraneous-c-p).

Of course, if there is not an 'insulating joint' and if there is electrical continuity through the meter, then bonding to something (ideally, 'if practicable', the pipe upstream of the meter) would be required.

I'm even more confused by this (my emphasis):

… insulating fittings shall be installed in all metal pipe, whether gas carrying or containing a PE liner, capable of providing electrical continuity between earth and the above ground pipework.

How on earth can an 'insulating fitting' ... 'provide electrical continuity' ??

Kind Regards, John

 

[EFLImpudence]

I was talking about gas pipes, not meters, and was observing that, to the best of my knowledge, insulating (presumably plastic) sections were not allowed in gas pipes within buildings (certainly domestic ones),

I presume that just applies to the consumer's pipework.
The suppliers, as is usual, seem to be allowed to do whatever they want.

such that the bit in the regs about 'insulation sections' presumably could not apply to gas pipes. However, I'm a bit confused by the article you linked to, since it seems to be saying that they are 'required'. Having said that, I can't quite work out whether they are installed outside or inside the building .... How would you interpret that?

No need to interpret:

Whatever, although, as above, I doubt whether the 'insulating section' bit of the reg can apply to gas pipes, the "or when there is a meter" bit certainly can, and that is where the reg's potential 'silliness' can arise (IF there is an 'insulating joint' and/or IF there is no electrical continuity through the gas meter - in either of which cases the regs would require one to bond something which wasn't an extraneous-c-p).

Yes, I know that. I am discussing the incorrectness the regulation.
I thought it was settled long ago that it was and is wrong.
You seem to be inventing ways in which it may not be.

Of course, if there is not an 'insulating joint' and if there is electrical continuity through the meter, then bonding to something (ideally, 'if practicable', the pipe upstream of the meter) would be required.

It would but the regulation says do not do that.

I'm even more confused by this (my emphasis): How on earth can an 'insulating fitting' ... 'provide electrical continuity' ??

I think you have misread it. You do seem to be doing that more frequently.
Try it this way:
" insulating fittings shall be installed in all metal pipe capable of providing electrical continuity between earth and the above ground pipework, whether gas carrying or containing a PE liner."

 

[EFLImpudence]

Forgot about this one:

I didn't have enough time to get involved in this yesterday, but commend you on your efforts.

Thank you.

A few initial observations:
Your Example 3 obviously raises an issue. As your note indicated, although this is 'correct' (electrical, in terms of the purpose of main boinding) it 'may be' (I would say "is" seemingly non-compliant with 544.1.2 (which nearly all of us believe is 'incorrect'). Given that there are people here of the view that one should comply with what regulations "actually say", even if we don't like it (e.g. because we don't think it is correct), is it appropriate that we should advise people to do what we believe to be 'correct', even if that makes it non-compliant with a regulation?

I think this is a case where the regulation is wrong.
Telling people would result in their installations being safer.

I realise that one of your aims is presumably to emphasise the point you often make (correctly) that 'isolated' bits of metal pipe do not need to be main bonded (and, arguably, 'should not' be main bonded). However, I wonder if, in your efforts to do this and to be 'comprehensive' are not making things over-complicated and hence potentially confusing. ...

Possibly, but it's a job to know where to stop - with what my intension was/is.

... your Example 5 is virtually never going to be seen. It is hard to imagine a situation with entirely metal pipework without there being a connection, somewhere, to a CPC - essentially, it could only happen if there were no boiler, no immersion and no CH. Although not impossible when there is a mixture of plastic and metal pipework, even Examples 2 and 4 (which are essentially electrically the same) are going to be pretty rare - since one wonders what those bits of isolated pipe will be supplying that does not invoke a connection to a CPC.

True, but I wanted to cover all possibilities and did not want a reaction to be "Yeah but what if?" to something I had not included.

If they are to be there, you could consider combining (2) and (4) into a single diagram, by having an 'insulating section' in both branches of the metal pipe.

Possibly.

It's probably the case that many of the questions about bonding relate to supplementary bonding in bathrooms, so it would perhaps be worthwhile considering corresponding diagram(s) for that. That could obviously be more complicated, since it will often be permissible to omit supplementary bonding , and there is the problem of defining what constitutes an extraneous-c-p (not simply a question of whether or not it is 'connected to true earth' as per your diagram).

Yes, I did think about SB but it will soon be a thing of the past with RCDs and there are so many variations.

IF - big IF - SB is required, it fundamentally boils down to: bond 'M' and 'T' pipes and not 'isolated', doesn't it?

Also should I change the title to something like "electrical connections of household pipework" rather than the narrow MPB?

Those are just my initial quick thoughts, to which you may wish to give some consideration. Keep up the good work!

Thank you.

 

[JohnW2]

I presume that just applies to the consumer's pipework. The suppliers, as is usual, seem to be allowed to do whatever they want.

Fair enough. However, I'm not sure that that is generally the case, since it is my understanding that when the gas supply pipe is plastic, they convert it to metal just before it enters the building, so as to avoid any plastic pipe within the building. That is certainly the case with my LPG pipework.

No need to interpret: ....

Thanks. The photo is not totally clear, but I must say that, if I didn't know better, I would think that was a metal-cased fitting with metal-to-metal fittings to pipes on both sides!

Yes, I know that. I am discussing the incorrectness the regulation.

So am I, other than that I called it 'silliness' rather than 'incorrectness'.

I thought it was settled long ago that it was and is wrong. You seem to be inventing ways in which it may not be.

It was settled long ago and is usually wrong. However, I just realised that that word 'usually' probably needs to be slipped in - because IF it is 'not practicable' to bond to the incoming pipe upstream of the meter and IF there is electrical continuity through the meter then the bonding (which would be required) would presumably have to be attached where the reg says. The other thing I've just realised is that even if the current meter does not have electrical continuity through it, one probably would have to bond (after the meter if not practicable before it), since one could not be sure that the meter would not subsequently be changed to one which did provide electrical continuity.

It would but the regulation says do not do that.

It does, and if it is practicable to bond upstream of the meter, then what the regs says is wrong.

Try it this way:
" insulating fittings shall be installed in all metal pipe capable of providing electrical continuity between earth and the above ground pipework, whether gas carrying or containing a PE liner."

Fair enough - yes, I see that's how it was meant to be read, and grammatically speaking does have that meaning. However, to be fair to myself, I don't think their wording was ideally clear (whereas yours is). Imagine they had written, say, "… insulating fittings shall be installed in all metal pipe, whether gas carrying or containing a PE liner, capable of preventing electrical continuity between earth and the above ground pipework.". Would you not have 'accepted' that wording and realised/assumed that the "capable of preventing..." referred to the insulated fitting, not the metal pipe?

Kind Regards, John

 

[JohnW2]

I think this is a case where the regulation is wrong. Telling people would result in their installations being safer.

You know that I agree with that, and the person most like to have had a problem with 'advising people to do something non-compliant with what the regulation actually says' has not yet said anything - so fair enough!

Possibly, but it's a job to know where to stop -

Agreed. What one has to try to decide is where 'increasing information and comprehensiveness' stops and 'overwhelming with information, and making it difficult to see the wood for the trees' starts.

True, but I wanted to cover all possibilities and did not want a reaction to be "Yeah but what if?" to something I had not included.

Yes, I understand that. However, since #2, #4 and #5 are all examples in which there no extraneous-c-ps and so no bonding is needed at all, I wonder if it might make sense to separate them from the otehrs and given them a separate 'title' of 'situations in which no bonding is required. Let's face it, #1 is by far the most common situation, and even #3 is fairly rare (for water) - so it's just those two which are of primary importance.

However, given our other discussions, you might want to consider expanding #3 to include gas pipes, primarily by redefining the grey bits as being "plastic pipe/insulating section/meter". In fact, it's also just occurred to me that the 'meter' business also applies to indoor water meters - and I am reminded that, in this respect, the regulation is very wrong in relation to my daughter's house, since there are a couple of metres of copper pipe under her kitchen sink etc. between water pipe entry and a meter.

Yes, I did think about SB but it will soon be a thing of the past with RCDs and there are so many variations.

Indeed. Even if you did consider addressing it, it would be a totally separate exercise.

IF - big IF - SB is required, it fundamentally boils down to: bond 'M' and 'T' pipes and not 'isolated', doesn't it?

Yes, I think so, but the problem we usually discuss is in determining/confirming 'T' and 'isolated', isn't it - with you usually saying that 'testing is required'?

Also should I change the title to something like "electrical connections of household pipework" rather than the narrow MPB?

I think you could probably usefully change the title, but I'm not certain about what you propose there. I'll think about it. You may even have to consider including the dreaded 'E-word' (presumably 'in quotes', followed by 'a lecture' in the text!), since many DIYers might be looking for that, rather than 'Bonding'!

Kind Regards, John

 

[John D v2.0]

Not sure whether this thread is the place, but we have an internal gas meter under the stairs with around 5m of old steel gas pipe coming under the suspended floor, then a couple of metres up to the stop valve, before the meter. The bonding is directly after the meter.
According to the diagrams I need to find a bonding clamp for the steel pipe and bond it either where it enters the floor void or where it appears from the floor instead of after the meter. Does anyone do that?

 

[bernardgreen]

The whole concept of Earth Ground, Earthing and Bonding is a compromised "solution" to the problems that have been created as a result of cost reduction in the local network. This solution cannot ensure safety in all situations. The cost saving was the combination of Neutral and imported "Earth" onto one conductor in the local network. Any damage or theft that breaks that conductor will create hazardous situations.

There are situations that arise and in these situations the "solution" does not protect the property and may, as in the incident here, create hazards that lead to damage risk of injury of death.

https://www.ifsecglobal.com/i4s-video-house-explosion-caught-on-cctv/

""Investigations have revealed that the blast was caused after a piece of cable was cut from an overhead line. This affected the earthing of the electrical network in the area and resulted in some unusual electrical activity, which affected some of the gas pipes within the properties. This resulted in the fires and explosion.

Ian Bitcon, WYFRS senior operations response officer, said: “If the house had exploded only seconds earlier, there is no doubt in my mind that it would have killed or seriously injured the occupants and the firefighters who were risking their lives to rescue them. We can’t stress enough how devastating this could have been. Instead, they lost their homes and possessions rather than their lives.""

 

[ban-all-sheds]

For some reason I am often criticised for suggesting that people should just read what the regulations say.

Nevertheless....

544.1.2 says "AT that point", not "AFTER that point".

#2, #4 & #5 show an 'at', #3 shows an 'after'.

 

[ban-all-sheds]

This is wrong and bonds pipes which are not e-c-ps and leaves unbonded the incoming pipe which is - and incidentally is also not as close as practicable to the point of entry.

You only think that all that happens because you are not correctly distinguishing between 'at' and 'after'.

 

[EFLImpudence]

Maybe - but we don't know if the authors were thinking like you or me.

I am at the window. Do I have to be touching it?

 

[EFLImpudence]

Also, Do you not consider the arrowed part in the picture to be at the point of entry?
How could it be fitted so that there was no external pipe visible or touchable?

I don't think we can get away from the fact that if you and John are correct then there is no need to have written the regulation at all as it makes the pipe not an extraneous-c-p.

 

[JohnW2]

Not sure whether this thread is the place, but we have an internal gas meter under the stairs with around 5m of old steel gas pipe coming under the suspended floor, then a couple of metres up to the stop valve, before the meter. The bonding is directly after the meter.

That is what the infamous regulation appears to 'require'.

According to the diagrams I need to find a bonding clamp for the steel pipe and bond it either where it enters the floor void or where it appears from the floor instead of after the meter. Does anyone do that?

That is what EFLI, myself, and I hope anyone else who understands the concept of main bonding thinks is what should be done.

IF there is no electrical continuity through your meter, then you have 5m of potentially touchable pipe that could, under certain circumstances, be at a very different potential from other simultaneously touchable things (i.e. those connected to your MET).

Whether anyone "does it", I don't know, but, in electrical terms, it is (in many of our opinions) what one should do to optimise safety.

Kind Regards, John

 

[ban-all-sheds]

At the point of entry means exactly that. After the point of entry is not at it, it is after it.

The arrow in the photo is pointing at a location after the point of entry.

But that is OK - 544.1.2 requires the connection to be made as near as practicable to the point of entry, i.e. at the minimum practical distance after it. It does not require it to be made at the point of entry.