Where to bond?

[JohnW2]

You can, as I said (meant) use pipes as supplementary bonds. However, it's difficult to see how it would be physically possible to use a pipe for main bonding. You wrote -

The lead pipe to the out house may be suitable to be used AS a protective bonding conductor...

Did you mean main bonding?

This is virtually identical to the discussion we had recently about an outhouse which contained a metal waterpipe which was in continuity (via the pipe) with bonded pipework in the house.

I argued at the time that one could probably regard the pipe as both an extraneous-conductive part (as far as the outhouse was concerned) and as (its own) 'main bonding conductor' (given that it represented a part of a path all the way back to the house's MET, all of which had at least the required CSA for a main bonding conductor). I argued that the only situation in which it would fail to fulfill that function as a 'main bonding conductor' would be that which would arise if the pipe were cut or interrupted - but that, if that ever happened, there would no longer be an extraneous-c-p which required bonding!

Electrically-speaking, that argument seems (to me!) to be pretty sound. Do you agree, but do you nevertheless think that it's an unacceptable argument/practice as far as the regs are concerned?

Kind Regards, John

 

[AndyPRK]

not that I have a clue but I would bond to the top pipe because

1. It's a clean bit of pipe so will have a good contact.
2. It connects to the rest of the installation

 

[JohnW2]

not that I have a clue but I would bond to the top pipe because
1. It's a clean bit of pipe so will have a good contact.
2. It connects to the rest of the installation

That might well be a pragmatic solution, but, as far as your (2) is concerned, it's not 'the rest of the installation' that one wants to bond to - rather, specificaly, the incoming (in this case outgoing!) water pipe (i.e. the extraneous conductive part). There are compression joints (on stopcock) between your proposed bonding point and the incoming/outgoing pipe. If someone was generous with PTFE tape (now, or in the future) on those joints, there may possibly not be electrical continuity across the stopcock - not to mention the possibility that someone might one day stick some plastic pipe or fittings in there somewhere. Wherever possible, it's safest to bond to whatever it is that actually needs to be bonded, to avoid such uncertainties.

Kind Regards, John

 

[JohnW2]

.... I argued that the only situation in which it would fail to fulfill that function as a 'main bonding conductor' would be that which would arise if the pipe were cut or interrupted - but that, if that ever happened, there would no longer be an extraneous-c-p which required bonding!

I've just realised that, although that was true of the recent 'outhouse' situation, it's not actually true of this thread - since that lead pipe goes underground, so a cut/interruption in it could still leave some underground pipe entering the toilet.

However, my argument still stands so long as the underground pipe is never cut/removed, which probably is extremely unlikely.

Kind Regards, John

 

[EFLImpudence]

This is virtually identical to the discussion we had recently about an outhouse which contained a metal waterpipe which was in continuity (via the pipe) with bonded pipework in the house.

Ah. true (did not think of that) but that's a bit different in that it was used to bond a second CU to the main one to export the earth...

so apologies to Lectrician if that's what he had in mind...

but that wouldn't apply in the case in RF's picture as the pipe does not require main bonding in the toilet.
If it DID require main bonding to the MET use of the pipe itself is not permissible and would negate the purpose of the exercise.

As in a single building, you cannot main bond an extraneous pipe, with 10mm² at the point of entry, by connecting it to the MET at its closest position (to the MET).
Using a different pipe which happens to run in the required route is fraught with difficulty, not least, the continuous conductor argument.

I argued at the time that one could probably regard the pipe as both an extraneous-conductive part (as far as the outhouse was concerned) and as (its own) 'main bonding conductor' (given that it represented a part of a path all the way back to the house's MET, all of which had at least the required CSA for a main bonding conductor). I argued that the only situation in which it would fail to fulfill that function as a 'main bonding conductor' would be that which would arise if the pipe were cut or interrupted - but that, if that ever happened, there would no longer be an extraneous-c-p which required bonding!

Precisely.

Electrically-speaking, that argument seems (to me!) to be pretty sound. Do you agree, but do you nevertheless think that it's an unacceptable argument/practice as far as the regs are concerned?

I do agree.

As far as the regs. are concerned it is acceptable if it is acceptable, i.e. if it complies and satisfies the requirements.
The pipe though still must be bonded as normal where it enters the property and in the shed.

 

[skenk]

Lead pipe that could introduce a potential=needs bonding in my book. Loop to somewhere reasonably practicable (left of hose connection?) for good measure and be done with it. The gas bond could even be extended with a straight crimp and looped in to save cable/if the run back to met is tricky.

 

[EFLImpudence]

Lead pipe that could introduce a potential=needs bonding in my book.

That's what we are discussing. I don't think anyone would disagree.

Loop to somewhere reasonably practicable (left of hose connection?) for good measure and be done with it.

Why loop? Bond as near as 'practicable'

The gas bond could even be extended with a straight crimp and looped in to save cable/if the run back to met is tricky.

Yes, but the thread is about 'where' not 'how'.

I'm sure RF knew the answer before he posted.

 

[Lectrician]

A main bond falls under "a protective conductor" as defined in the regs.

Protective bonding conductor. Protective conductor provided for protective equipotential bonding

Protective conductor (PE). A conductor used for some measures of protection against electric shock and intended for connecting together any of the following parts:
(i) Exposed-conductive-parts
(ii) Extraneous-conductive-parts
(iii) The main earthing terminal
(iv) Earth electrode(s)
(v) The earthed point of the source. or an artificial neutral.

543.2.2 A protective conductor may consist of one or more of the following:
(i) A single-core cable
(ii) A conductor in a cable
(iii) An insulated or bare conductor in a common enclosure with insulated live conductors
(iv) A fixed bare or insulated conductor
(v) A metal covering, for example, the sheath, screen or armouring of a cable
(vi) A metal conduit, metallic cable management system or other enclosure or electrically continuous support
system for conductors
(vii) an extraneous-conductive-part complying with Regulation 543.2.6.

543.2.6 Except as prohibited in Regulation 543.2.1, an extraneous-conductive-part may be used as a
protective conductor if it satisfies all the following requirements:
(i) Electrical continuity shall be assured, either by construction or by suitable connection, in such a way as to
be protected against mechanical, chemical or electrochemical deterioration
(ii) The cross-sectional area shall be at least equal to that resulting Irol11 the application of Regulation 543.1.1
(iii) Unless compensatory measures are provided, precautions shall be taken against its removal
(iv) It has been considered for such a use and, if necessary. suitably adapted.

This means you could use an extraneous conductive part as a main bond if you see fit, and adhere to the points in the regs, as a main bonding conductor is also known as a protective conductor.

My comments was to suggest that there would be no point main bonding it as it is in effect bonded already, and is itself suitable to be used a main bonding conductor, so could bond other things too.

We have had these discussions with the NIC below with scenarios given such as a detached garage with the house gas meter in it, and a galv gas pipe between the two, and a steel structure warehouse with a water service in a diagonal corner to the mains intake.

 

[skenk]

That's what we are discussing. I don't think anyone would disagree.

So no problem with me adding to the thread then? (although it seems to me the the chat had yet again drifted off into another boring back-and-forth between the forum-dwellers, rather than a discussion of the photo posted)

Why loop? Bond as near as 'practicable'

Belt & braces? helping to avoid confusion for plumbers and sparks about position of incoming supply in future? stopping some box ticker complaining later that there is no bonding on the incoming service?

Yes, but the thread is about 'where' not 'how'.

Oh well excuse me, and you go right ahead and carry on your boring waffling with the other forum-dwellers in in thread after thread. pfft

This place has really gone downhill!

 

[EFLImpudence]

This means you could use an extraneous conductive part as a main bond if you see fit, and adhere to the points in the regs, as a main bonding conductor is also known as a protective conductor.

But it is not possible to use an extraneous-conductive-part to bond itself.
That would be connecting one e-c-p to another which is already main bonded.

My comments was to suggest that there would be no point main bonding it as it is in effect bonded already, and is itself suitable to be used a main bonding conductor, so could bond other things too.

Not quite sure what you mean.

If you mean the lead pipe in the toilet - this would not require a main bond anyway (unless there were another CU in the toilet, then I agree) but you cannot use the pipes connected to the lead as a main bond for that lead.
It could be connected to the gas pipe but only because/if that were already bonded effectively.

We have had these discussions with the NIC below with scenarios given such as a detached garage with the house gas meter in it, and a galv gas pipe between the two,

But would it require a main bond?

and a steel structure warehouse with a water service in a diagonal corner to the mains intake.

Accepted but the steel itself will be main bonded.

I may have been limiting my thoughts to domestic premises, for example, where the gas and water may be connected together and connected to the MET by cable
but you may not just connect the two together and use one of the pipes as a route to the MET.

 

[EFLImpudence]

That's what we are discussing. I don't think anyone would disagree.

So no problem with me adding to the thread then? (although it seems to me the the chat had yet again drifted off into another boring back-and-forth between the forum-dwellers, rather than a discussion of the photo posted)

Why loop? Bond as near as 'practicable'

Belt & braces? helping to avoid confusion for plumbers and sparks about position of incoming supply in future? stopping some box ticker complaining later that there is no bonding on the incoming service?

Yes, but the thread is about 'where' not 'how'.

Oh well excuse me, and you go right ahead and carry on your boring waffling with the other forum-dwellers in in thread after thread. pfft

This place has really gone downhill!

Sorry, didn't realise you were not interested in joining in when you joined in.

 

[RF Lighting]

Ha ha I thought this thread might get a few people going

I know it's immaterial in the real world, where the actual physical connection to the pipework is, as long as it gets connected.

I think regulation 544.1.2, and section 4.4 of the OSG make it pretty clear that the bonding needs to be connected just above the toilet stop cock, behind the grey waste pipe, and this is the only connection required for the water supply.

 

[JohnW2]

This means you could use an extraneous conductive part as a main bond if you see fit, and adhere to the points in the regs, as a main bonding conductor is also known as a protective conductor.

But it is not possible to use an extraneous-conductive-part to bond itself. That would be connecting one e-c-p to another which is already main bonded.

I think it could get worse/sillier than that, because, if one adopts Lectrician's viewpoint, I don't think it would be necessary for the extraneous-conductive-part to be "already main bonded" (at the correct place).

He seems to be arguing that, so long as 543.2.6 is satisfied, an extraneous-c-p can be used as a main bonding conductor. If one takes that view, then it presumably could be used to provide most of the path which 'bonded itself', from the point at which bonding should be connected (close to entry into the premises) to somewhere way along the pipework (near the CU?) where it was convenient to make a connection to the MET.

Hence, if you follow Lectrician's view to its logical conclusion, and provided one could satisfy 543.26.6 [particularly 543.2.6(iii)], it would mean that one could usually main bond an extraneous-c-p like a water supply pipe as far from the point of entry into the premises as one wanted (was convenient) ... and I really find it hard to believe that the regs intended to be allowing that! Although you pteviously wrote (and most of us would totally agree):

As in a single building, you cannot main bond an extraneous pipe, with 10mm² at the point of entry, by connecting it to the MET at its closest position (to the MET).

... Lectrician appears to be trying to argue that the regs, as written, would indeed allow that. Apart from the contradiction which it would create with 544.1.2, I have not yet found anything specific in the regs I could cite to refute his argument...can you?

Kind Regards, John

 

[JohnW2]

Ah. true (did not think of that) but that's a bit different in that it was used to bond a second CU to the main one to export the earth... so apologies to Lectrician if that's what he had in mind... but that wouldn't apply in the case in RF's picture as the pipe does not require main bonding in the toilet.
If it DID require main bonding to the MET use of the pipe itself is not permissible and would negate the purpose of the exercise.

I must confess that I did think that Lectrician was talking about the situation (hypothetical - aka untrue in terms of RF's actual situation) in which there was electricity (not necessarily a CU) in the outside toilet, and hence there was a need for main bonding of the pipe which entered that outside building.

However, as I subsequently noted in my follow-up message, my original argument is, in RF's case, weakened by the fact that the lead pipe is underground - so that (however improbable) it could be broken/interrupted, but still leave the need to main bond in the toilet (a requirement which would not be met if the pipe itself was being used as part of the only means of 'main bonding' to the MET.

Kind Regards, John

 

[Lectrician]

I would always Mbond with 600mm, before tees etc, or where practicable if pushed, and would not like to do it any other way.

I just thought I would throw in something to argue about

A discussion with the NIC following a PIR a while ago (we get inspected for EICR's too, not just installs) brought up this matter.

We had made an observation of the main bonding to the water service simply being connected to the steel structure of the building. The water bond was done at the stop tap, and then just lugged to a bolt through a steel column. This was within maybe 15m of the mains intake, so lazy. The NIC pretty much said "what if it was the other side of the building, would you expect a cable run back then?". This is when he brought up the use of an extraneous part. I had always known about this for supp bonding, but had always assumed it was not permitted with a main bond.