Is this earth wire a problem?

[sparkwright]

Or, should it be read as
600 mm of the meter union if the meter is external
or
600 mm at the point of entry to the building if the meter is external

Bloody book.

 

[JohnW2]

Or, should it be read as
600 mm of the meter union if the meter is external ... or ... 600 mm at the point of entry to the building if the meter is external ... Bloody book.

Quite so.

However, this whole discussion is almost certainly moot in the OP's case, since, being a new build, it is all but certain that the gas supply pipe will be plastic, in which case there will be no (gas-related) extraneous-c-p that needs to be bonded, anywhere.

Kind Regards, John

 

[sparkwright]

True.

 

[CBW]

in which case there will be no (gas-related) extraneous-c-p that needs to be bonded, anywhere.

Kind Regards, John

Please forgive me as I’m not bright/thick. If a live/line was able to touch an extraneous pipe, there’s no p.d. because the incoming gas is plastic?

 

[JohnW2]

Please forgive me as I’m not bright/thick. If a live/line was able to touch an extraneous pipe, there’s no p.d. because the incoming gas is plastic?

If the incoming pipe were plastic, hence not connected to earth, if the internal metal pipework would come into a live/line conductor then the pipe's PD relative to earth would rise to (obviously dangerous) line/live potential relative to earth.

If the internal pipework also had no connection to earth, then that (dangerous) PD would persist. However, in practice, such metal pipework invariably IS earthed, by it's connection to a boiler if nothing else, in which case the fact that it had become live would almost instantly cause a breaker to trip (or fuse to blow), thereby removing the danger.

More generally, you need to understand that the purpose of "bonding" (as opposed to "earthing") is not to deal with situations such as you describe, but to prevent an incoming pipe (which, externally, was in contact with 'true earth') being at appreciably different potential from all the 'earths' within an electrical installation (which will not necessarily be at 'true earth' potential, even 'normally', and certainly not under certain fault conditions).

Kind Regards, John

 

[EFLImpudence]

Surely this could be interpreted/misinterpreted as
600 mm of the meter outlet union if the meter is external
or
at the point of entry to the building if the meter is external

That doesn't make sense.

Either it is within the 600mm. if the meter is external (which it isn't) or
at the point of entry if the meter is external (which it is).

Try this:
"Where practicable the connection shall be made within 600 mm of the meter outlet union
or
at the point of entry to the building if the meter is external."


It is only the gas people demanding that the bond shall not be connected to the supply side of the internal meter which causes all the confusion.

Have you added the heavy type?

Yes, I have separated and emphasised the one long paragraph to to make it clearer.

I obviously failed.

 

[JohnW2]

Try this:
"Where practicable the connection shall be made within 600 mm of the meter outlet union
or
at the point of entry to the building if the meter is external."

We've discussed this umpteen times before, and some degree of ambiguity arises because, in the absence of punctuation and/or parenthesis, it can be read as

"(Where practicable the connection shall be made within 600 mm of the meter outlet union or at the point of entry to the building) if the meter is external."

OR

"(Where practicable the connection shall be made within 600 mm of the meter outlet union) or (at the point of entry to the building if the meter is external.)"

However, as said, and even though it's Friday night, this is probably moot in terms of this thread, since the OP's new build house will almost certainly have no gas-related extraneous-c-ps which need to be main-bonded anywhere.

Kind Regards, John

 

[sparkwright]

"Where practicable the connection shall be made within 600 mm of the meter outlet union
or at the point of entry to the building if the meter is external."

Heavy type or no heavy type...

Where practicable the connection shall be made {within 600 mm of the meter outlet union or at the point of entry to the building} IF the meter is external.

Where practicable the connection shall be made {within 600 mm of the meter outlet union} or {at the point of entry to the building if the meter is external}. *

Where practicable the connection shall be made {within 600 mm of the meter outlet union} or {at the point of entry to the building} if the meter is external.

I had to write the sentence out like this to try to understand it. I think the first and third lines would be the same.

The second line, with the '*' at the end, must be the correct way to read it, but does {within 600 mm of the meter outlet union} include INSIDE an EXTERNAL meter box? It implies I can still connect to the pipe inside an external box. Or I can choose to do where the pipe from the external box enters the inside of the house.

So, in summary, I can do the bonding inside the external meter box (where incoming gas supply is metal), can't I?

 

[EFLImpudence]

You are all forgetting the first sentence of 544.1.2.

The rest of it qualifies that because of the gas people not wanting the bonding conductor in the correct place on the supply pipe, i.e. forbidding bonding at the point of entry when the meter is inside.
This obviously does not apply to external meters.

 

[EFLImpudence]

The second line, with the '*' at the end, must be the correct way to read it, but does {within 600 mm of the meter outlet union} include INSIDE an EXTERNAL meter box? It implies I can still connect to the pipe inside an external box. Or I can choose to do where the pipe from the external box enters the inside of the house.
So, in summary, I can do the bonding inside the external meter box (where incoming gas supply is metal), can't I?

Yes, IF that is the point of entry; not if the meter box is a long way away - e.g. at the bottom of a block of flats.

 

[EFLImpudence]

Take a flat on the fist floor or higher where the gas pipe runs down the wall to the meters at ground level.

Do you really think the regulation means you can connect the bond at the point of entry or within 600mm. of the meter outlet?

What would be the sense in that?

 

[JohnW2]

You are all forgetting the first sentence of 544.1.2.

Am I included in that "all", given that I wrote ..

However, this whole discussion is almost certainly moot in the OP's case, since, being a new build, it is all but certain that the gas supply pipe will be plastic, in which case there will be no (gas-related) extraneous-c-p that needs to be bonded, anywhere.

Kind Regards, John

 

[sparkwright]

For some reason I cannot quote John's quote of his own passage about the gas pipe probably being new plastic and not needed to be bonded and discussion being moot - YET it's still good to talk about things, it's never stopped other topics going off the boil and although the topic has often been discussed, I can't say I've ever had much to say about it.

So - to confirm - are we saying a first floor flat with a meter box at ground level should only be bonded inside the flat, as near as practicable to where the pipe enters the flat?
I have witnessed many a gas engineer condemning such a thing, where he has expected it to be in the gas meter box.

On a different token, I have seen upstairs flats individually bonded inside the flat where the pipe enters, AND a bonding cable from the communal supply going to all gas meter boxes for all the flats on the outside wall of the building.

 

[JohnW2]

For some reason I cannot quote John's quote of his own passage about the gas pipe probably being new plastic and not needed to be bonded and discussion being moot ...

The 'quoting facility in this forum doed not include a 'quoting of quotes' - so if you want to include things that were quoted in the post you are quoting from, you have to 'add them yourself'.

- YET it's still good to talk about things, it's never stopped other topics going off the boil and although the topic has often been discussed, I can't say I've ever had much to say about it.

All true, but we need to keep OPs in mind - and I didn't want the OP in this thread to get confused by all that was being discussed, given that it is very likely that none of his gas pipework needs main boding anywhere.

So - to confirm - are we saying a first floor flat with a meter box at ground level should only be bonded inside the flat, as near as practicable to where the pipe enters the flat?

That is certainly what 'electrical common sense' would say, since the whole purpose of main bonding is to create an equipotential zone within the flat. Of course, as above, if the incoming gas pipe is not an extraneous-c-p (because the supply pipe to the meter is plastic, and the meter is above ground), then no main bonding is needed anywhere.

I have witnessed many a gas engineer condemning such a thing, where he has expected it to be in the gas meter box.

I can't answer for gas engineers - maybe they are less conversant with 'electrical common sense'?

On a different token, I have seen upstairs flats individually bonded inside the flat where the pipe enters, AND a bonding cable from the communal supply going to all gas meter boxes for all the flats on the outside wall of the building.

It's all a bit 'belts and braces', given that all the earths/bonding, and all the (necessarily metal) gas pipes, within the building, will be electrically connected together, but some might argue that communal parts of the building should have main bonding, just as should the individual flats, but that's not really anything to do with the electrical installation of an individual flat.

Having said that, and going back to 'electrical common sense', IF there IS an extraneous-c-p entering the building, and if that is main bonded where it enters the building, then the whole building should have been rendered an equipotential zone, such that main bonding in individual flats should not be required.

Kind Regards, John

 

[EFLImpudence]

Am I included in that "all", given that I wrote ..

Well, yes because you were rephrasing the rest of the regulation (after the first sentence) to try and make it apply to an external meter.

Bearing in mind what the first sentence says, then it is obvious that the subsequent wording only applies to internal meters.

Would anyone think it applied to water meters under the pavement?