Does this pipework need bonding?

[ADS]

ah, good point,and, does it now form part of the electrical installation now you have bonded it at a seperate location?

It will never be part of the 'electrical installation' - it's part of the 'gas installation'.

My opinion, anyway, is no, it won't introduce a potential, so don't bond - so I wouldn't have bonded it at a seperate location.

 

[springcrocus]

Hi Springcrocus,The only question you have to ask yourself is does the gas pipe, (where it re-enters the building), fit the definition of an 'Extraneous Conductive Part'.................in other words, does it introduce a potential, 'earth' or otherwise, to the building.

That's it.....simple.

If it does - bond it.

If it doesn't - don't bond it.

Extraneous Conductive Part - A conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.

But I find myself asking other questions such as...will the resultant earth loop create a problem? Any likelihood of circulating currents creating a problem?

Maybe it's not so simple? I don't know.

 

[Manator]

It will never be part of the 'electrical installation' - it's part of the 'gas installation'. My opinion, anyway, is no, it won't introduce a potential, so don't bond - so I wouldn't have bonded it at a seperate location.

Differences in potentials can give some disturbing results to the human body, its better to test than to go with the flow that any RCD will save them. I would agree that in a domestic environment the size of the install will have minute potential differences, but I would never allow myself to ever be complacent.

 

[ADS]

Sorry, I've just re-read your OP.

I based my 'don't bond' opinion on the pipe already being bonded by the 'T'.

I now realise that you say it runs under the kitchen floor, (how far??), before being bonded.

So now I don't have an opinion - as Manator says, you'ld have to test it where it enters the bathroom.

 

[steptoe]

It will never be part of the 'electrical installation' - it's part of the 'gas installation'. My opinion, anyway, is no, it won't introduce a potential, so don't bond - so I wouldn't have bonded it at a seperate location.

wasnt really a question for you.

but, back to the point,

how do we decide if a pipe needs bonding or not?

then, does this pipe need bonding?

 

[ADS]

But I find myself asking other questions such as...will the resultant earth loop create a problem? Any likelihood of circulating currents creating a problem?Maybe it's not so simple? I don't know.

It's a piece of metal entering the bathroom - it's either extraneous or not.............you'ld have to test it and see............nothing else has a bearing on 'bonding' it.

 

[steptoe]

It's a piece of metal entering the bathroom - it's either extraneous or not.............you'ld have to test it and see............nothing else has a bearing on 'bonding' it.

I'd agree,

that may not be the only consideration, depending on the condition of the rest of the install, esp as its in a bathroom,

but that is deffo the first excerise.

 

[springcrocus]

It will never be part of the 'electrical installation' - it's part of the 'gas installation'. My opinion, anyway, is no, it won't introduce a potential, so don't bond - so I wouldn't have bonded it at a separate location.

If that is the case, then surely the original pipework won't introduce a potential either. Would you, therefore, not bond this either?

 

[steptoe]

why would the second pipe introduce a potential?

it has already been taken to your MET potential,

as said,

test it and see.

 

[springcrocus]

I'm not typing as fast as everybody else so it's getting a bit out of sync.

A long-lead test gave a reading of 0.06 ohms from the gas pipe at the boiler to the MET. I didn't mention this in the OP as I didn't want to muddy the water too much.

 

[ADS]

wasnt really a question for you.but, back to the point,

how do we decide if a pipe needs bonding or not?

then, does this pipe need bonding?

You divide the nominal voltage to earth of the installation by the current that you wish not to exceed and then take away the hand to hand impedance of the human body.

Your answer will be in ohms.

If the measured resistance between the 'conductive part' in question and the MET of the installation is bigger than this answer, then the 'conductive part' is not 'extraneous'.

Unfortunately, in the OPs example, the pipework is already bonded to the MET, so the measured resistance reading is going to be a lot lower than the answer to the equation, so you are looking for something different........I'll let you tell us what......?

---------- Post Auto-Merged at 23:09 ---------- Previous post was made at 23:04 ----------

I'm not typing as fast as everybody else so it's getting a bit out of sync.A long-lead test gave a reading of 0.06 ohms from the gas pipe at the boiler to the MET. I didn't mention this in the OP as I didn't want to muddy the water too much.

I'd say you have to bond it, then.

 

[binky]

20mm gas pipe, soldered joins providing extremely good conductive path, bonded at (or very near) where pipe pops out of ground and where it has a MEB (twice apparently) how many bonds do you need???? Certainly no more in bathroom unless it needs cross bonding. As for extraneous conductive part, of course it is - boiler has mains leccy supply running to lots of metal things like pumps which are connected to copper things called pipes. Unless of course electrical items in boiler are class II insulated. I know it's late and I'm rather tired, but aren't we rather making mountains out of mole hills here....bit like over zealous H&S rep on building sites??

 

[Steve3948]

Is it likely to become live, at 0.06 ohms back to MET I think not.

 

[sellers]

Can i just point out, after having my AC assessment today,

You cannot just omit cross bonding if all your bathroom circuits are RCD protection, you have to also ensure your pipes measure less than 1667ohms back to the MET.

 

[ADS]

20mm gas pipe, soldered joins providing extremely good conductive path, bonded at (or very near) where pipe pops out of ground and where it has a MEB (twice apparently) how many bonds do you need???? Certainly no more in bathroom unless it needs cross bonding. As for extraneous conductive part, of course it is - boiler has mains leccy supply running to lots of metal things like pumps which are connected to copper things called pipes. Unless of course electrical items in boiler are class II insulated. I know it's late and I'm rather tired, but aren't we rather making mountains out of mole hills here....bit like over zealous H&S rep on building sites??

If the pipe that re-enters the building is 'extraneous', then it requires 'bonding' - from where it re-enters the building, back to the MET.

We're not making mountains out of molehills, it's the Regs............I work to the Regs, does anyone else?

I know exactly what the OP is talking about because I have a very similar situation in my house.

The gas main comes up through the floor in the understairs cupboard.

There, it connects to the meter.

It's then 'bonded' on my side of the meter. It then 'T's off.......one section goes to feed my cooker and gas fire, the other section leaves the building through the wall, goes up the outside of the house, then re-enters into the back of a cupboard on the first floor, and connects to the boiler.

Where my pipe re-enters, it is not extraneous and therefore is not bonded.

---------- Post Auto-Merged at 23:34 ---------- Previous post was made at 23:33 ----------

Is it likely to become live, at 0.06 ohms back to MET I think not.

That isn't the issue.

---------- Post Auto-Merged at 23:38 ---------- Previous post was made at 23:34 ----------

Can i just point out, after having my AC assessment today,You cannot just omit cross bonding if all your bathroom circuits are RCD protection, you have to also ensure your pipes measure less than 1667ohms back to the MET.

I'm going to hazard a guess and say you're NICEIC - this has got to be one of their 'quirky' rules.

 

[SLIPSHOD & SLAPDASH]

I was hoping to promote a bit of discussion but it seems I was trying to float a lead balloon..

You can float a lead balloon, they did it on Mythbusters.

You cannot fly a lead balloon.

busted

Adam and Jamie constructed a cube-shaped balloon with approximately 2 meter edges using lead foil. Even without pure helium inside it (a mixture containing air was used), the balloon had enough buoyancy to lift a basket weighing several pounds.

Now that the forum is under new management I may write a few articles to lay aside a few myths about earthing and bonding..

Why does that matter ?

 

[springcrocus]

Just to recap, the tee is external and there are now two separate feeds to the house, unlike the situation that ADS has where he can bond before the tee inside the house. Moving the bonding to the outside, before the tee, is not how we would do it hence the question.

 

[Manator]

You can float a lead balloon, they did it on Mythbusters.You cannot fly a lead balloon.

busted

Adam and Jamie constructed a cube-shaped balloon with approximately 2 meter edges using lead foil. Even without pure helium inside it (a mixture containing air was used), the balloon had enough buoyancy to lift a basket weighing several pounds.

Why does that matter ?

It does not matter, its more of, the new management are introducing some very new concepts that most forums never see. Keep logging in because you will be amazed at the results.

 

[steptoe]

If the pipe that re-enters the building is 'extraneous', then it requires 'bonding' - from where it re-enters the building, back to the MET.We're not making mountains out of molehills, it's the Regs............I work to the Regs, does anyone else?

I know exactly what the OP is talking about because I have a very similar situation in my house.

The gas main comes up through the floor in the understairs cupboard.

There, it connects to the meter.

It's then 'bonded' on my side of the meter. It then 'T's off.......one section goes to feed my cooker and gas fire, the other section leaves the building through the wall, goes up the outside of the house, then re-enters into the back of a cupboard on the first floor, and connects to the boiler.

Where my pipe re-enters, it is not extraneous and therefore is not bonded.

---------- Post Auto-Merged at 23:34 ---------- Previous post was made at 23:33 ----------

That isn't the issue.

---------- Post Auto-Merged at 23:38 ---------- Previous post was made at 23:34 ----------

I'm going to hazard a guess and say you're NICEIC - this has got to be one of their 'quirky' rules.

I dont, I have never made any secret of that fact,

IMHO some of the things in the regs are plain ridiculous.

I generally supersede BS7671's requirements,

generally I use them as a base,

sometimes I dont comply with them, but I always ensure I comply with a higher requirement as a minimum.

 

[ADS]

I dont, I have never made any secret of that fact,IMHO some of the things in the regs are plain ridiculous.

I generally supersede BS7671's requirements,

generally I use them as a base,

sometimes I dont comply with them, but I always ensure I comply with a higher requirement as a minimum.

Fair enough.