18th 544.1.2

[EFLImpudence]

By who?

I don't know; you brought up the subject.

This is not possible it is a required part of the system.

Ok. Previous reply applies then.

Purposly said I would not use technical terminology to avoid clouding the issue.

It cannot be avoided sometimes. What was the term you think technical?

Is the main zone not intended to be from the moment you enter the front door of the property?

I do not know what the main zone is.

Supplementry, again correct me, is to ensure that a particular area that is of higher risk e.g. bathroom, within the property, is at a consistant voltage level so eliminating the risk of shock?

Yes, more or less. Apart from the main bonding to incoming services, all other bonding is supplementary - supplementary(in addition) to the main bonding.

Scenario - gas boiler develops earth fault and earth wire in flex has failed boiler casing becomes live and, if water and gas pipes not connected together, they also become live. Is that a safe situation? Touch outside tap or the pipe I previously described and it could be curtains.

And you called my spoon analogy poor. Fit two flexes if you want.
Substitute tap/pipe for spoon.

By who and where is this ammended?

The latest edition of the wiring regulations, 411.3.1.2 and 544.1.2.

Their pipe no doubt is earthed in a way satisfoacory to them.

It might. The house is not their consideration.

But now consider the scenario where a fault has developed within the property. Main supply is MDPE so there is no need to cross bond meter connections. Meterman cops it. Likewise main supply is MDPE underground is transitional fitting to steel pipe, up outside wall and 90degree fitting to meter position. that would also become live to anybody touching it, and that length of pipe could be in a public place.

The only way to avoid that is insulating sections to all the pipe work where it is connected to electrical equipment.
Plumbers do not seem to do that.

 

[EFLImpudence]

Just to add - electricity, like gas, is dangerous.
All safety measures are a compromise to negate the most likely faults.
There is always an example of an unlikely fault where doing something else would have been better.

I could go on the gas forum and say despite all your best work, what if a leak developed, If I lit a fag my house would blow up.

 

[EFLImpudence]

Further on this part:

Scenario - gas boiler develops earth fault and earth wire in flex has failed boiler casing becomes live

That's two faults happening at once - or one going unnoticed until the second. Poor maintenance

and, if water and gas pipes not connected together, they also become live.

Why do you say because they are not connected together?

Is that a safe situation?

Both pipes will become live by being connected to the boiler, in which case it would be better if they were not connected to the boiler but that is unavoidable in a normal installation.

However, and it may be central to your thinking - what difference do you think connecting the two pipes with a wire would make - not to mention the other three or four pipes nor the fact that that is not the purpose of bonding?

Touch outside tap or the pipe I previously described and it could be curtains.

It could - what do you recommend?

More wires to assist the electricity in its journey or insulating sections to halt its path?

 

[AlanE]

Theoretical debates can go on forever. Go back to square 1 and supply a bit of evidence to say bonding (of any description) of gas pipe within 600 mm or where it enters the domestic property, as required by already quoted gas regs, is wrong and unecessary.

That would presumeably require proving reg 411.3.1.2 is also wrong and same with 544.

Or maybe it is with the perceived definition of extraneous. Does it refer to outside the property or, more likley, is it simply refering to metal outside the immediate remit of the electrical installation.

Metal in an electrical circuit is the wiring and any fixed metal equipment such as consumer unit. Every other bit of metal is extraneous to the electrical installation.

 

[EFLImpudence]

Theoretical debates can go on forever.

For goodness' sake; it's NOT theoretical. It is only going on for ever because you don't understand and keep questioning me.

Go back to square 1 and supply a bit of evidence to say bonding (of any description) of gas pipe within 600 mm or where it enters the domestic property, as required by already quoted gas regs, is wrong and unecessary.

There is no of any description; it is Main Bonding.
Where there is an insulating section, the consumer's side is NOT an extraneous-conductive-part therefore it does not require main bonding, but the supply pipe likely is and therefore does.
Where there is not an insulating section and the consumer's pipework is electrically connected to the supply pipe then the consumer's pipework is likely an extraneous-conductive-part and therefore should be bonded at the point of entry.
It does not actually matter electrically where the pipe is bonded but the point of entry is stipulated so that the extraneous bit is not disconnected (from the MET) by any alterations to the pipework.

That would presumeably require proving reg 411.3.1.2 is also wrong and same with 544.

They were, for years, wrong and have now been rectified in the latest regulations which have just been published now stating what I have been telling you.
Very likely your gas regulations will catch up, but why it has been incorrect for years I have no idea.
Well, I have so perhaps your gas regulation authors are no better.

Or maybe it is with the perceived definition of extraneous. Does it refer to outside the property or, more likley, is it simply refering to metal outside the immediate remit of the electrical installation.

It referes to metal entering the premises from outside the equipotential zone (the building).

Metal in an electrical circuit is the wiring and any fixed metal equipment such as consumer unit. Every other bit of metal is extraneous to the electrical installation.

It is but it is not extraneous to the installation but wholely within the building which is the criterion - a lump of metal (or a spoon) on a table would make no difference; it has NO potential.
It is extraneous to the premises that matters and whether it is liable to introduce a potential to the premises - a pipe which has been running in the ground might be at a different potential to the installation earth.

 

[denso13]

Very likely your gas regulations will catch up

Seems that the guidance has at least http://www.agsm.uk.com/wp-content/u...ding-on-gas-pipework-in-domestic-premises.pdf

 

[JohnW2]

Seems that the guidance has at least http://www.agsm.uk.com/wp-content/u...ding-on-gas-pipework-in-domestic-premises.pdf

... albeit only about 6 weeks ago (whereas the requirements for main bonding (or not) in electrical regulations have been essentially unchanged for decades).

However, on the basis of a quick read, it looks as if the relevant parts of that document merely reproduce the BS7671 regulations we have been discussing, and do not explicitly emphasise (or even mention) the fact that a metal gas pipe entering a property may not be an extraneous-conductive part, and therefore not subject to the bonding requirements in 411.3.1.2 and 544.1.2 - and I strongly suspect that many non-electrician readers of the document may still miss that crucial point.

Kind Regards, John

 

[333rocky333]

I always thought the EXTRANEOUS bit only refered to metal if it was in contact with the ground, either outside, or inside under the floor etc ,not just the fact its outside.
You wouldnt bond a surface metal conduit run on an outside wall or a metal garden tap on your outside kitchen wall would you.

 

[EFLImpudence]

Actually AlanE did quote that passage on Thursday.

... albeit only about 6 weeks ago (whereas the requirements for main bonding (or not) in electrical regulations have been essentially unchanged for decades).

The principles haven't changed for decades but 544.1.2 did wrongly tell people to bond the consumer's side of the insulatig section.

However, on the basis of a quick read, it looks as if the relevant parts of that document merely reproduce the BS7671 regulations we have been discussing, and do not explicitly emphasise (or even mention) the fact that a metal gas pipe entering a property may not be an extraneous-conductive part, and therefore not subject to the bonding requirements in 411.3.1.2 and 544.1.2 - and I strongly suspect that many non-electrician readers of the document may still miss that crucial point.

That is true - perhaps it might be useful to point out that a plastic supply pipe can also be termed 'an insulating section'.

 

[EFLImpudence]

I always thought the EXTRANEOUS bit only refered to metal if it was in contact with the ground, either outside, or inside under the floor etc ,not just the fact its outside.

Yes, that is true.

You wouldnt bond a surface metal conduit run on an outside wall or a metal garden tap on your outside kitchen wall would you.

No, because it is NOT an extraneous-conductive-part - which is the bit people fail to take into account.

 

[JohnW2]

I always thought the EXTRANEOUS bit only refered to metal if it was in contact with the ground, either outside, or inside under the floor etc ,not just the fact its outside.

It refers to metal entering the property which is "liable to introduce a potential, usually earth potential". As you say, in practice that essentially means metal which is, at some point, in contact with the ground (or in electrical continuity with something which is in contact with the ground).

Any situations I can think of in which a metal object was "liable to introduce a potential" which was NOT earth potential are so far-fetched as to not (in my opinion) to warrant consideration!

You wouldnt bond a surface metal conduit run on an outside wall or a metal garden tap on your outside kitchen wall would you.

No, as above, not if it went nowhere near the ground.

There are grey areas. My next-door-neighbour has a metal oil-supply pipe which runs for a fair distance along the bottom of his outside walls (with some of it having concrete or paving going right up to the wall), in some places probably only a couple of cm above the ground (or concrete/paving). Given that it wouldn't take much of a 'flood' to give that pipe some electrical path to earth, I would personally think that it should be bonded, even though it wouldn't need it under dry conditions (and measurements undertaken under non-flood conditions would 'confirm' that bonding was not required).

Kind Regards, John

 

[333rocky333]

Oh and i dont mean bond outside metal garden chairs

 

[333rocky333]

Oh and i dont mean bond outside metal garden chairs

Edit
I realised what i said whilst you were typing

 

[AlanE]

Seems that the guidance has at least http://www.agsm.uk.com/wp-content/u...ding-on-gas-pipework-in-domestic-premises.pdf

Thanks for that denso. Not being gas registered now it takes some time for me to obtain latest TB's. Guidence in that hasen't changed really just been updated to reflect latest wiring reg details.

 

[JohnW2]

Thanks for that denso. Not being gas registered now it takes some time for me to obtain latest TB's. Guidence in that hasen't changed really just been updated to reflect latest wiring reg details.

Indeed, and nor have the 'wiring reg details' in relation to this matter really changed for decades. The change in the most recent (July 2018) version of the Wiring Regs is a fairly subtle change of wording, which may make it a bit easier for some people to understand, but it has always been the case in terms of the Wiring Regs that something which is not an extraneous-conductive-part does not require 'PEB', whether it is a gas supply pipe or anything else.

Unfortunately, the Wiring Regs still do not say that explicitly. It ought to be apparent to people reading the regs (both current and earlier versions) that, since they state (only) that extraneous-conductive-parts must have main bonding, it is thereby implicit that anything which is NOT and extraneous-conductive part is NOT required to have main bonding - but many people, including a good few electricians, do not seem to have grasped that.

As I recently wrote, I think the problem with that recent gas guidance is that it will probably still be misunderstood by many non-electricians' (and probably a good few electricians) because, although it quotes all the relevant electrical regs, it does not explicitly point out that a gas supply pipe entering a property does NOT necessarily require 'PEB' because it NOT necessarily an extraneous-conductive part.

Kind Regards, John