UK Earthing Arrangement

[Tonychitty]

Can anyone help, i had a new combi boiler fitted last year and they used mainly plastic fittings to make there connections, i have attached a photo below my question is where should my 10mm earth bond go , the incoming water pipe is made of lead, do i simply bond the 10mm earth to the incoming water pipe with a suitable clamp and then bridge the plastic plumbing tee to the nearest copper pipe.
any feedback would be mostly appreciated

 

[telectrix]

looks like the plastic has eliminated the need for bonding. the only extraneous metal pipework appears to be the incoming up to the plastic. test any copper to MET. above 22k Ohms, not extraneous. if < a couple ohms, it's bonded elsewhere, e.g. to the gas at the bolier. and what's that torpedo above the stop. is it a filter?

 

[pc1966]

Assuming the existing bond is 10mm then yes, put a new clamp on to the lead pipe and run another bit of 10mm up to join the existing bonding cable. Ideally you should join them with a crimp or soldering so if any one screw loosens you don't have multiple bond wires separating.

Is there a separate bond wire to the gas meter already?

 

[davesparks]

looks like the plastic has eliminated the need for bonding. the only extraneous metal pipework appears to be the incoming up to the plastic. test any copper to MET. above 22k Ohms, not extraneous. if < a couple ohms, it's bonded elsewhere, e.g. to the gas at the bolier. and what's that torpedo above the stop. is it a filter?

The torpedo is a magnetic scale inhibitor, generally required by most manufacturers for their combi boilers
[automerge]1591442417[/automerge]

Assuming the existing bond is 10mm then yes, put a new clamp on to the lead pipe and run another bit of 10mm up to join the existing bonding cable. Ideally you should join them with a crimp or soldering so if any one screw loosens you don't have multiple bond wires separating.

Is there a separate bond wire to the gas meter already?

Why? That can be left exactly as it is, the bonding should be connected after the stopcock, not before it.
And I certainly wouldn't fit a pipe clamp to a soft lead pipe.

 

[Tonychitty]

Assuming the existing bond is 10mm then yes, put a new clamp on to the lead pipe and run another bit of 10mm up to join the existing bonding cable. Ideally you should join them with a crimp or soldering so if any one screw loosens you don't have multiple bond wires separating.

Is there a separate bond wire to the gas meter already?

Yes there is, can i not loop in and out with the 10mm earth bond with an ordinary bs951

 

[bill01803]

Replace the plastic tee with a compression - job done (presuming the filer is metal)

 

[Tonychitty]

Assuming the existing bond is 10mm then yes, put a new clamp on to the lead pipe and run another bit of 10mm up to join the existing bonding cable. Ideally you should join them with a crimp or soldering so if any one screw loosens you don't have multiple bond wires separating.

Is there a separate bond wire to the gas meter already?

yes there is
[automerge]1591443071[/automerge]

looks like the plastic has eliminated the need for bonding. the only extraneous metal pipework appears to be the incoming up to the plastic. test any copper to MET. above 22k Ohms, not extraneous. if < a couple ohms, it's bonded elsewhere, e.g. to the gas at the bolier. and what's that torpedo above the stop. is it a filter?

is a magnetic scale inhibitor,
Source URL: UK - Earthing Arrangement - https://www.electriciansforums.net/threads/earthing-arrangement.187131/#post-1633862

 

[Tonychitty]

looks like the plastic has eliminated the need for bonding. the only extraneous metal pipework appears to be the incoming up to the plastic. test any copper to MET. above 22k Ohms, not extraneous. if < a couple ohms, it's bonded elsewhere, e.g. to the gas at the bolier. and what's that torpedo above the stop. is it a filter?

is a magnetic scale inhibitor,
Source URL: UK - Earthing Arrangement - https://www.electriciansforums.net/threads/earthing-arrangement.187131/#post-1633862

 

[pc1966]

Why? That can be left exactly as it is, the bonding should be connected after the stopcock, not before it.

Really, why?

Normally I don't trust plumbing joints for electrical function even when they are all metal and should be good as I have seen oddities before.

And I certainly wouldn't fit a pipe clamp to a soft lead pipe.

That is fair enough. A strip of sandpaper cleaning up the painted copper pipe just before the stopcock would have enough for the clamp and be the best place in my opinion.

Other opinions are available, just wait...
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Yes there is, can i not loop in and out with the 10mm earth bond with an ordinary bs951

If you have the cable to do it, yes.

Usually the "best practice" is to avoid breaks/screw connections in bonding wires, though it is not actually mentioned in the BS regulations, so a screw coming loose has less impact (a bit like the guidance for high leakage CPC arrangements). So if the wire is short then you could use a crimp joint to extend it, then loop round the existing far-end clamp to your new one.

You probably don't need the far-end clamp, but easiest to leave it and it won't upset the plumber who next comes to do maintenance.

 

[telectrix]

it won't upset the plumber who next comes to do maintenance.

where's the fun in that?

 

[Tonychitty]

looks like the plastic has eliminated the need for bonding. the only extraneous metal pipework appears to be the incoming up to the plastic. test any copper to MET. above 22k Ohms, not extraneous. if < a couple ohms, it's bonded elsewhere, e.g. to the gas at the bolier. and what's that torpedo above the stop. is it a filter?

What if the plastic tee in the future gets replaced with a metal one, should i not put a the option of a bonding clamp after the plastic tee

 

[pc1966]

What if the plastic tee in the future gets replaced with a metal one, should i not put a the option of a bonding clamp after the plastic tee

Sir, put down the plumbing and walk away solely...

Just add another clamp, extending wire as needed. Quick and easy to do, not worth the trouble of trying to re-use a clamp anyway, avoids complaints of anything else not being adequately bonded as a result. Sorted!

 

[radiohead]

Nothing there requires bonding, either leave it as it is or disconnect it entirely.

 

[pc1966]

Nothing there requires bonding, either leave it as it is or disconnect it entirely.

Not even the cold water pipe / stopcock / filter as an extraneous conductive part that is clearly within normal touch access?

You could argue the boiler water pipes are no longer part of such a system, but the cold pipe is still something I would bond.

Also you might just find it is like my flat where some muppet of a plumber has split the cold pipe below the floor and I have two stopcocks, one for bathroom and the other for the kitchen! So the plastic pipes visible in the shower/bath did not reflect on the electrical connectivity to the kitchen.

For years I could not find the 2nd stopcock and then when the gas board need to move the meter (no longer allowing central riser feed, had to go outside) they put it in my kitchen and cut through the back of the under sink cupboard for pipe access.

And lo! The missing stopcock was found!

Yes, folks the (possibly same) group that had built the kitchen had hidden the stopcock behind a permanent backing panel, oh FFS!

 

[Tonychitty]

Nothing there requires bonding, either leave it as it is or disconnect it entirely.

even though there is a metallic water pipe coming in from the outside, i do have the 10mm eath cable near by should i just connect it anyway.

 

[radiohead]

even though there is a metallic water pipe coming in from the outside, i do have the 10mm eath cable near by should i just connect it anyway.

Pointless above the plastic joint. Nowhere really viable below. If you really think it's necessary clamping it carefully it onto the lead wont do any harm.

 

[ipf]

even though there is a metallic water pipe coming in from the outside, i do have the 10mm eath cable near by should i just connect it anyway.

But the lead incomer's not electrically connected to anything internal.
...and if the plastic T is replaced, it would be bonded anyway (if that's the 10mm you're on about).

 

[Tonychitty]

Pointless above the plastic joint. Nowhere really viable below. If you really think it's necessary clamping it carefully it onto the lead wont do any harm.

is it worth bridging out the plastic tee with a short piece of 10mm so that all other copper in the installation is earthed.
[automerge]1591460371[/automerge]

But the lead incomer's not electrically connected to anything internal.
...and if the plastic T is replaced, it would be bonded anyway (if that's the 10mm you're on about).

as the 10mm is near by is there any arm in connecting it anyway will it make the installation unsafe

 

[telectrix]

if the copper pipes in the propery are not extraneous, they can't introduce an earth potential , so bonding them is pointless. as The Borg say "resistance is futile".

 

[pc1966]

if the copper pipes in the propery are not extraneous, they can't introduce an earth potential , so bonding them is pointless. as The Borg say "resistance is futile".

But the lead pipe is!

 

[telectrix]

so bond the lead pipe. easy sweat a connection to that. even a plumber could do it.

 

[pc1966]

I think that is his question: should the incoming lead pipework be bonded?

Probably the boiler no longer requires bonding, but no point in removing it either. However, the lead pipe, stopcock, and filter are all extraneous parts and accessible to touch so should be bonded.
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Ah, just missed your reply!

 

[Tonychitty]

if the copper pipes in the propery are not extraneous, they can't introduce an earth potential , so bonding them is pointless. as The Borg say "resistance is futile".

but there would be if there was not a plastic tee piece

 

[pc1966]

but there would be if there was not a plastic tee piece

That becomes irrelevant if the incoming pipe is bonded.

 

[Tonychitty]

looks like the plastic has eliminated the need for bonding. the only extraneous metal pipework appears to be the incoming up to the plastic. test any copper to MET. above 22k Ohms, not extraneous. if < a couple ohms, it's bonded elsewhere, e.g. to the gas at the bolier. and what's that torpedo above the stop. is it a filter?

but should the lead pipe up to the plastic tee not be bonded as it can be touched
[automerge]1591462718[/automerge]

so bond the lead pipe. easy sweat a connection to that. even a plumber could do it.

is there no suitable clamps for lead

 

[telectrix]

but should the lead pipe up to the plastic tee not be bonded as it can be touched

strictly speaking, yes, but then can you touch any electrical equipment at the same time?

 

[Tonychitty]

strictly speaking, yes, but then can you touch any electrical equipment at the same time?

there will be a washing machine going there

 

[telectrix]

there will be a washing machine going there

so... unless you pull the machine out and it simultaneously develops an electrical fault whilst you are turning off the water stop cock, at the same time a pink pig is flying past the window, riding on a winged elephant?????

 

[Tonychitty]

so... unless you pull the machine out and it simultaneously develops an electrical fault whilst you are turning off the water stop cock, at the same time a pink pig is flying past the window, riding on a winged elephant?????

i know, my problem is that i dont fully understand in my head what earth actually is i just think everthing needs bonding together and not fully understanding it all, but thanks for your input most appreciated.
i have looked on youtube trying to find earthing for dummies.

 

[Jim_e_Jib]

If the lead pipe supplies drinking water, I'd be inclined to replace it. A length of MDPE pipe and no more worries over bonding or lead contamination

 

[Tonychitty]

If the lead pipe supplies drinking water, I'd be inclined to replace it. A length of MDPE pipe and no more worries over bonding or lead contamination

yes i have been looking at that in the last couple of days that can be very expensive digging up the front garden.

 

[telectrix]

If the lead pipe supplies drinking water, I'd be inclined to replace it. A length of MDPE pipe and no more worries over bonding or lead contamination

that would entail a lot of digging up. all the way back to the water main in the strreet, which is probably rusty iron anyway.

 

[westward10]

This has got far too complicated. The lead service pipe requires a main protective bond.

 

[Tonychitty]

found this on the internet it mentions if you have an incoming plastic water pipe you do not need to main bond, however if the rest of the pipework there after is metal you will require main earth bonding, i have highlighted it. this is driving me mad any one shed some light please.

 

[westward10]

You do not have an all insulated service pipe. This thread has become over complicated, that lead pipe requires a main protective bond.

 

[Tonychitty]

You do not have an all insulated service pipe. This thread has become over complicated, that lead pipe requires a main protective bond.

last one promise, the rest of the copper in the installation after the plastic tee still requires main earth bonding no

 

[radiohead]

I'll try and shed some light for you.
In the event of a fault on your electrical system conductive parts (ie earthed metal parts of the electrical installation such as a metal light fitting or washing machine case) may experience a rise in potential relative to the general mass of earth which is at zero volts or thereabouts. Within a building that rise in potential is unlikely to be a serious hazard because a person in contact with a conductive part during the fault is likely to be stood on an electrically insulating surface such as a wooden floor. However the metallic water service is in contact with the general mass of earth and will introduce that potential into the building. Now there is a hazard because a person may be in contact with both a conductive part and the water service at the same time the fault is in progress and subject to a shock. By bonding both together the possibility of a potential difference is reduced. Where there is an insulating section immediately after the water service enters the property the rest of the copper pipework in the house has effectively been disconnected from the general mass of earth and so does not require bonding because it can no longer introduce an earth potential.
In your case the rest of the house pipework is isolated from the earth potential by the plastic joint, only the short section of lead and the filter are extraneous. As Tel stated what are the chances of contact between that and a conductive part for the duration of a fault? If you think there is then bond the lead. But you DO NOT NEED TO BOND THE REST OF THE PIPEWORK AFTER THE PLASTIC JOINT. In fact doing so may actually increase the shock risk in the event of a fault.
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last one promise, the rest of the copper in the installation after the plastic tee still requires main earth bonding no

NO!

 

[davesparks]

This has got far too complicated. The lead service pipe requires a main protective bond.

Main bonding should be on the consumers side of the stopcock, the lead pipe is before the stopcock, therefore the bond should be on the copper and not the lead.

 

[Tonychitty]

I'll try and shed some light for you.
In the event of a fault on your electrical system conductive parts (ie earthed metal parts of the electrical installation such as a metal light fitting or washing machine case) may experience a rise in potential relative to the general mass of earth which is at zero volts or thereabouts. Within a building that rise in potential is unlikely to be a serious hazard because a person in contact with a conductive part during the fault is likely to be stood on an electrically insulating surface such as a wooden floor. However the metallic water service is in contact with the general mass of earth and will introduce that potential into the building. Now there is a hazard because a person may be in contact with both a conductive part and the water service at the same time the fault is in progress and subject to a shock. By bonding both together the possibility of a potential difference is reduced. Where there is an insulating section immediately after the water service enters the property the rest of the copper pipework in the house has effectively been disconnected from the general mass of earth and so does not require bonding because it can no longer introduce an earth potential.
In your case the rest of the house pipework is isolated from the earth potential by the plastic joint, only the short section of lead and the filter are extraneous. As Tel stated what are the chances of contact between that and a conductive part for the duration of a fault? If you think there is then bond the lead. But you DO NOT NEED TO BOND THE REST OF THE PIPEWORK AFTER THE PLASTIC JOINT. In fact doing so may actually increase the shock risk in the event of a fault.
[automerge]1591478252[/automerge]

NO!

im finally starting to get it thanks for finding the time and effort explaining this most appreciated

 

[radiohead]

Main bonding should be on the consumers side of the stopcock, the lead pipe is before the stopcock, therefore the bond should be on the copper and not the lead.

It should be but as can be seen from the picture that is not really possible. If the OP feels the need to bond the short section of extraneous lead before the insulating joint I see no reason why it cant go on the lead.

 

[westward10]

Main bonding should be on the consumers side of the stopcock, the lead pipe is before the stopcock, therefore the bond should be on the copper and not the lead.

You know full well that by some means or other that pipework requires a main protective bond.

 

[davesparks]

It should be but as can be seen from the picture that is not really possible. If the OP feels the need to bond the short section of extraneous lead before the insulating joint I see no reason why it cant go on the lead.

It is already connected to the first available bit of copper after the stopcock, and anybody can see that the plastic fitting is not a long enough insulating section to negate the need for bonding.

As long as you can find a clamp suitable for fitting to a lead pipe then yes an additional connection can be made to it, lead being a soft material will continue to move and give way over time so a normal pipe clamp will become loose over time and so is not suitable.
[automerge]1591479076[/automerge]

You know full well that by some means or other that pipework requires a main protective bond.

Yes, and it already has a main bond connected as required to the first available bit of solid metal pipe on the consumers side of the point of isolation.

 

[Tonychitty]

It is already connected to the first available bit of copper after the stopcock, and anybody can see that the plastic fitting is not a long enough insulating section to negate the need for bonding.

As long as you can find a clamp suitable for fitting to a lead pipe then yes an additional connection can be made to it, lead being a soft material will continue to move and give way over time so a normal pipe clamp will become loose over time and so is not suitable.

It is already connected to the first available bit of copper after the stopcock, and anybody can see that the plastic fitting is not a long enough insulating section to negate the need for bonding.

As long as you can find a clamp suitable for fitting to a lead pipe then yes an additional connection can be made to it, lead being a soft material will continue to move and give way over time so a normal pipe clamp will become loose over time and so is not suitable.
[automerge]1591479076[/automerge]


Yes, and it already has a main bond connected as required to the first available bit of solid metal pipe on the consumers side of the point of isolation.

they are not connected to the main bond the plumber connected it this way to his cross bonding on combi pipes
[automerge]1591481807[/automerge]

I'll try and shed some light for you.
In the event of a fault on your electrical system conductive parts (ie earthed metal parts of the electrical installation such as a metal light fitting or washing machine case) may experience a rise in potential relative to the general mass of earth which is at zero volts or thereabouts. Within a building that rise in potential is unlikely to be a serious hazard because a person in contact with a conductive part during the fault is likely to be stood on an electrically insulating surface such as a wooden floor. However the metallic water service is in contact with the general mass of earth and will introduce that potential into the building. Now there is a hazard because a person may be in contact with both a conductive part and the water service at the same time the fault is in progress and subject to a shock. By bonding both together the possibility of a potential difference is reduced. Where there is an insulating section immediately after the water service enters the property the rest of the copper pipework in the house has effectively been disconnected from the general mass of earth and so does not require bonding because it can no longer introduce an earth potential.
In your case the rest of the house pipework is isolated from the earth potential by the plastic joint, only the short section of lead and the filter are extraneous. As Tel stated what are the chances of contact between that and a conductive part for the duration of a fault? If you think there is then bond the lead. But you DO NOT NEED TO BOND THE REST OF THE PIPEWORK AFTER THE PLASTIC JOINT. In fact doing so may actually increase the shock risk in the event of a fault.
[automerge]1591478252[/automerge]

NO!

so this is wrong then i have highlighted in yellow
[automerge]1591482568[/automerge]

they are not connected to the main bond the plumber connected it this way to his cross bonding on combi pipes
[automerge]1591481807[/automerge]

so this is wrong then i have highlighted in yellow

and is the small plastic tee enough of an insulater to negate no main bonding

 

[marconi]

https://electrical.------.org/wiring-matters/years/2019/75-may-2019/to-bond-or-not-to-bond/

To bond or not to bond....is worth a read.

In this reference it says:

In addition, the following statement has been added to Regulation 411.3.2.

“Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding.”

I hope this is helpful to answering the OP's question.

nota bene: TonyChitty - I do not in the EF ever provide public advice on the wiring regulations - all I have done is point out an IET reference on the subject. Take the sage advice of the professional electricians who know the WRs much better than me and how to apply them in particular circumstances.

 

[radiohead]

It is already connected to the first available bit of copper after the stopcock, and anybody can see that the plastic fitting is not a long enough insulating section to negate the need for bonding.

I disagree with that entirely, any plastic insert between two sections of copper pipe will electrically isolate one section from the other. If that was not the case it would be a requirement to bridge any plastic joints on copper pipework with a copper conductor. It is not a requirement.
[automerge]1591517092[/automerge]

they are not connected to the main bond the plumber connected it this way to his cross bonding on combi pipes
[automerge]1591481807[/automerge]

so this is wrong then i have highlighted in yellow
[automerge]1591482568[/automerge]

and is the small plastic tee enough of an insulater to negate no main bonding

It is not wrong and the plastic tee is sufficient to negate the need for bonding on the rest of the pipework

 

[Pretty Mouth]

TonyChitty, here's how I like to think about it:

Think about the path the current would take if a human were to receive a shock while simultaneously touching an exposed conductive part, and an (unbonded) extraneous metal pipe, while a fault to earth occurred.

From the transformer, the current would pass through:
1 - Line conductor
2 - Faulty exposed conductive part
3 - Human
4 - Metal pipe
5 - Metal pipe at point of entry to building
6 - General mass of earth
7 - Neutral pole of transformer.

Without bonding, there is a large potential difference between point 2 and 4, so the human gets a shock.

By bonding the metal pipe at the point of entry to the building, the potential between point 2 and point 5 are equal if an earth fault occurs. No current will flow between these points, and the human is safe.

This is why we bond at the point the point the pipe enters the building - it doesn't matter what you put between points 4 and 5 - plastic joints, pipework, and so on - the potential between 2 and 5, and everything in between, is still equal, so no current flows between these points.

 

[Tonychitty]

TonyChitty, here's how I like to think about it:

Think about the path the current would take if a human were to receive a shock while simultaneously touching an exposed conductive part, and an (unbonded) extraneous metal pipe, while a fault to earth occurred.

From the transformer, the current would pass through:
1 - Line conductor
2 - Faulty exposed conductive part
3 - Human
4 - Metal pipe
5 - Metal pipe at point of entry to building
6 - General mass of earth
7 - Neutral pole of transformer.

Without bonding, there is a large potential difference between point 2 and 4, so the human gets a shock.

By bonding the metal pipe at the point of entry to the building, the potential between point 2 and point 5 are equal if an earth fault occurs. No current will flow between these points, and the human is safe.

This is why we bond at the point the point the pipe enters the building - it doesn't matter what you put between points 4 and 5 - plastic joints, pipework, and so on - the potential between 2 and 5, and everything in between, is still equal, so no current flows between these points.

I'll try and shed some light for you.
In the event of a fault on your electrical system conductive parts (ie earthed metal parts of the electrical installation such as a metal light fitting or washing machine case) may experience a rise in potential relative to the general mass of earth which is at zero volts or thereabouts. Within a building that rise in potential is unlikely to be a serious hazard because a person in contact with a conductive part during the fault is likely to be stood on an electrically insulating surface such as a wooden floor. However the metallic water service is in contact with the general mass of earth and will introduce that potential into the building. Now there is a hazard because a person may be in contact with both a conductive part and the water service at the same time the fault is in progress and subject to a shock. By bonding both together the possibility of a potential difference is reduced. Where there is an insulating section immediately after the water service enters the property the rest of the copper pipework in the house has effectively been disconnected from the general mass of earth and so does not require bonding because it can no longer introduce an earth potential.
In your case the rest of the house pipework is isolated from the earth potential by the plastic joint, only the short section of lead and the filter are extraneous. As Tel stated what are the chances of contact between that and a conductive part for the duration of a fault? If you think there is then bond the lead. But you DO NOT NEED TO BOND THE REST OF THE PIPEWORK AFTER THE PLASTIC JOINT. In fact doing so may actually increase the shock risk in the event of a fault.
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NO!

if i do bond the lead pipe back to the MET am i not in theory reconnecting the extraneous part back into the system any way as my gas pipe is also connected to it and with the combination boiler all supplementry bonded together all the copper will be connected anyway

 

[radiohead]

There's no reason not to bond both the lead and copper if that's what you want to do. My contention is that it is not required to bond the copper past the plastic joint, and debatable whether there is sufficient extraneous lead present even for that to be required. But if you feel the need go ahead, it wont do any harm.

 

[Tonychitty]

There's no reason not to bond both the lead and copper if that's what you want to do. My contention is that it is not required to bond the copper past the plastic joint, and debatable whether there is sufficient extraneous lead present even for that to be required. But if you feel the need go ahead, it wont do any harm.

Thanks for explaining this to me in great detail thankyou and everyone that replied to my original post.

 

[DPG]

Good debate this one.