More on meters and 544.1.2

[JohnW2]

In the course of participating in another thread, it has occurred to me that my house quite probably does not practise what I am preaching, so I’m interested to try to clarify interpretations of 544.1.2 of the regs. As we recently discussed (but did not really reach a conclusion), 544.1.2 contains a potential ambiguity. It says:

“When there is an insulating section or insert at that point, or there is a meter, the connection should be made to the consumer’s hard metal pipework....”

If they were working to strict grammatical rules, the existence of those two commas would remove any ambiguity, such that the meaning was:

• “... (when there is an insulating section or insert at that point) OR (when there is a meter) ...”

In other words, if there is a meter, then what follows those phrases applies regardless of where the meter is. However, others seem to interpret it as meaning:

• “...when there is an insulating section, insert or meter at that point ...”

...which would mean that what followed only applied to a meter if it were ‘at that point’ (i.e. very close to the point of entry of the service into the premises)

I think we are all agreed that any connection from the MET to pipework downstream of any ‘insulating section’ in the pipework is not Main Protective Bonding, could possibly (albeit rarely) increase hazards and actually leaves the one bit of pipework that theoretically does need MPB without it – so that whole section of 544.1.2 seems ‘wrong’. However, that aside, and since I didn’t really sense any true consensus from our recent discussion, I wonder which of the above interpretations (as regards meters) people think is what the regs intend? I realise that the OSG confuses matters even further, but it’s the regs themselves that really interest me – the OSG probably represents nothing more than the attempt of someone (perhaps no more able than us) to decide what the regs intended!

Kind Regards, John

 

[EFLImpudence]

“When there is an insulating section or insert at that point, or there is a meter, the connection should be made to the consumer’s hard metal pipework....”

If they were working to strict grammatical rules, the existence of those two commas would remove any ambiguity, such that the meaning was:

But the two commas ARE there and it is they which introduce the ambiguity.
If the commas were not there and I don't think they should be because, I think, the condition applies if the meter is also 'at that point'.

It would obviously be wrong should the meter be a distance away on the other side of the house (although it wouldn't be) to bond there.

I realise that the OSG confuses matters even further, but it’s the regs themselves that really interest me –

Agreed.

the OSG probably represents nothing more than the attempt of someone (perhaps no more able than us) to decide what the regs intended!

Considerably less in some instances but why is it necessary to interpret especially as the interpreters seem no better informed as to the intent?

Unfortunately, as in this case, the actual regulations are no better.

 

[JohnW2]

“When there is an insulating section or insert at that point, or there is a meter, the connection should be made to the consumer’s hard metal pipework....”

If they were working to strict grammatical rules, the existence of those two commas would remove any ambiguity, such that the meaning was:

But the two commas ARE there and it is they which introduce the ambiguity.

I don't really agree with that. If the intended meaning is as you believe, what's really wrong is the word order - i.e. 'meter', just like 'insulating section or insert' should really appear before 'at that point'. However, given the word order they have adopted, the two commas result in creation of a separate ('standalone') clause, which would be regarded gramatically as saying "or [if] there is a meter", unaffected by the previous (before the first comma) 'at that point'.

If the commas were not there and I don't think they should be because, I think, the condition applies if the meter is also 'at that point'. It would obviously be wrong should the meter be a distance away on the other side of the house (although it wouldn't be) to bond there.

You say 'obvious', but I'm not sure that it necessarily is (in terms of the regs, not electrical principles and common sense) Unlike the matter of a meter, what the regs say about an 'insulating section or insert' is unambiguous - contrary to the whole concept of main bonding, they seem obsessed with 'bonding' the MET to the consumer's side of an electrical interuption in the service pipe (i.e. to the house's internal pipework, which is insulated from the extraneous-c-p). Since I wouldn't have dreamed of writing that myself, I wouldn't like to be the one to try to second guess what they 'intended' in relation to a meter which 'interrupted' the pipework!

Kind Regards, John

 

[ericmark]

I have been trying to work out what it means and to do that I have split into the three items.

1) Gas (town) clearly there will be a meter and all before the meter will not be "the consumer’s" property so within 600mm on consumers side of meter but not onto any flexible pipework.

2) Water here often no meter and if there is often not in the premises so the consumer’s hard metal pipework. Where the problem arises is when there is no hard metal pipework.

3) Other for that I will read oil and LPG. Here I see a real problem. Again likely no meter but where there is a meter this may be anywhere as not for charging and not owned by supplier but owned by the the consumer. With oil and gas stored in a tank there is a problem in that when filling those tanks the supply vehicle will need earthing. With plastic tanks used with oil again a problem and also electrolysis has to be considered. I think today plastic is used a lot with oil so again not really a problem so that leaves LPG.

So in real terms the question is how to earth a LPG (tanked gas) supply? I don't like admitting but I don't know. Neither do I know who the tank belongs to. This is of course a very dangerous fuel I remember it wiping out a camp site in France of British tourists.

I would guess there are very strict rules today and the BS7671 is written in a way so it will not be in conflict with the LPG rules.

I watch with interest for answers.

 

[EFLImpudence]

Yes, I agree with what you say regarding the regulation as it is written but, as you say, this is not correct electrically or if common sense is employed so ...

As I have said before, there are numerous threads on various forums and no one seems able to understand why it is the case that bonding should be on the consumer's side of an insulating section.
The most plausible reasoning is that if the pipe is NOT extraneous because of the insulating section then 544.1.2 does not apply.

What is this insulating section - on a gas supply?

If insulating sections were introduced at all necessary points on the water pipes to purposely isolate them in order to make them not extraneous then what?


As for 544.1.2 itself, all that is really needed is the first sentence.

The last sentence demands that the bonding is always to be connected to the consumer's side of the meter, wherever it is.
This cannot be right unless the meter is always at the point of entry or external which I suppose it is.

 

[JohnW2]

Yes, I agree with what you say regarding the regulation as it is written but, as you say, this is not correct electrically or if common sense is employed so ... As I have said before, there are numerous threads on various forums and no one seems able to understand why it is the case that bonding should be on the consumer's side of an insulating section. The most plausible reasoning is that if the pipe is NOT extraneous because of the insulating section then 544.1.2 does not apply.

That's certainly an interesting way of looking at it. Indeed, that viewpoint makes the wording 544.1.2 even more silly, since all but the first sentence would then be redundant, since it relates to a situation which can't arise! Maybe I'm being excessively generous, but I find it hard to believe that even those who wrote the reg can't be quite that daft - they surely must have believed that all that extra they wrote in 544.1.2 would be applicable in at least some situations!

What is this insulating section - on a gas supply?

Quite so. My understanding is that such sections would not be allowed within premises. Even if there are some eosoteric non-conducting materials that would be allowed, they're not used. However, I don't think we should be too critical of the regs about this. It is a generic paragraph about all services, so 'insulating sections' are simply 'not applicable' in relation to gas pipes.

If insulating sections were introduced at all necessary points on the water pipes to purposely isolate them in order to make them not extraneous then what?

You and I know what we think. However, it seems that 544.1.2 is generally taken to mean that, nevertheless, the house's metal pipework would need main bonding - but, as you say above, the alternative argument is that 544.1.2 itself becomes N/A in the absence of an extraneous-c-p

As for 544.1.2 itself, all that is really needed is the first sentence.

Quite so.

The last sentence demands that the bonding is always to be connected to the consumer's side of the meter, wherever it is.

Indeed. that was the point I was discussing.

This cannot be right unless the meter is always at the point of entry or external ...

Indeed. Electrically, 'it cannot be right', but ....

... which I suppose it is.

Not always, hence the main reason for this thread! My (internal) water meter is some 3-4m from the point of entry of the service, the intervening pipe being highly exposed.

The other issue which we've discussed in the past, is that of whether or not all water meters are necessarily 'insulating'. Mine looks as if it probably is (or was, before Mr Anglian Water put an ~4mm G/Y strap across it ), but they might not (all) be. If water meters are not necessarily 'insulating' that confuses the discussion even more, since 544.1.2 could be saying that one has to bond on the consumer's side of a meter (wherever it is) even if it is not 'insulating'.

Kind Regards, John

 

[Porque223]

Seems that the rulemakers are not certain if a meter provides electrical continuity or not, so you are to bridge it with a conductor.

If you apply Symbolic Logic to the NEC all kinds of ambiguities come out. In writing rules I guess I'd aim for 95% of the users to understand what I've written. Examples also help, what is meant and what is not meant, but the NEC is a bit short on this.

Do a thought experiment as to what might happen if you
bridge a meter that is nonconducting
bridge a meter that is conducting
not bridge a meter that is nonconducting
not bridge a meter that is conducting

You are trading off material cost and labor time for increased safety. Hopefully a clear winner jumps out.

BTW, with a lantern battery & lamp, a DVM and four test leads you can measure resistance in the milliohm range.

 

[JohnW2]

Seems that the rulemakers are not certain if a meter provides electrical continuity or not, so you are to bridge it with a conductor.

The UK electrical regs say absolutely nothing about such bridging. As I said, the water supply company put a 'bridge' (albeit of inadequate CSA for main bonding!) across my meter when they fitted it, but that's nothing to do with the electrical regs!

If you apply Symbolic Logic to the NEC all kinds of ambiguities come out. In writing rules I guess I'd aim for 95% of the users to understand what I've written.

[
I'm afaraid that in terms of what we're discussing, it's hard to find anyone (let alone 95%!) who understands what they intend by what they've written - and, in terms of what many feel they probably intend, most of us think it's plain wrong!

Kind Regards, John

 

[EFLImpudence]

Seems that the rulemakers are not certain if a meter provides electrical continuity or not, so you are to bridge it with a conductor.

No that is the point. There is no requirement to bridge the insulating section thus leaving the part in the ground unbonded.

BTW, with a lantern battery & lamp, a DVM and four test leads you can measure resistance in the milliohm range.

Oh, we have meters for that (upto 25kΩ would be sufficient) but the pipes entering the premises will be connected to numerous parts and electrical circuits so making total disconnection for actual measurement very time consuming and because of these connections unnecessary bonding is not detrimental.

 

[EFLImpudence]

Is the mistake in the second sentence that it says 'insulating' (n.b. not isolating) and, indeed, would it make more sense if 'insulated' were used?

 

[JohnW2]

Is the mistake in the second sentence that it says 'insulating' (n.b. not isolating) and, indeed, would it make more sense if 'insulated' were used?

That's an interesting new idea! However, whereas "insulated section" might make some sense (e.g. plastic coated metal pipe), I'm not really sure that "insulated insert" would. I fear that, as we've always previously assumed, they really do mean insulating/isolating.

However, in the other direction, "insulated" would actually introduce a means of applying the wording to gas pipes!

I suspect this interesting thought is a red herring, but who knows?!

Kind Regards, John

 

[EFLImpudence]

It doesn't actually say 'insulating insert'

... (insulated section) or (insert) at that point, ...

 

[JohnW2]

With oil and gas stored in a tank there is a problem in that when filling those tanks the supply vehicle will need earthing.

What is needed is bonding (of tanker to storage tank), not earthing, and they are fastidious about that (always seem to take a long time to connect it - maybe they even bolt it on). When I have my LPG tank filled, they bond it to the tanker with an extremely fat looking cable.

So in real terms the question is how to earth a LPG (tanked gas) supply? I don't like admitting but I don't know.

My tank appears to have no explicit earthing (I'll check tomorrow, if I remember, just to be sure!). The first few feet of the underground feed from it is metal, before turning into plastic, but I saw that pipe going in, and it was heavily wrapped with tape and a bitumin-like substance, so it probably affords little connection to earth. As above, the crucial thing is (temporary) bonding to the delivery vehicle.

Kind Regards, John

 

[JohnW2]

It doesn't actually say 'insulating insert' ... (insulated section) or (insert) at that point, ...

Oooh - you're trying to get even more clever

The problem with that idea is that, if you include those 'imaginery brackets' the word 'insert' is then not qualified by anything (insulated, insulating or whatever) and therefore would not (IMO) make much sense.

Kind Regards, John

 

[EFLImpudence]

It could be a lead to copper adaptor meaning the bond should be connected to the copper pipe and not the lead.