Supplementary bonding required with RCD's?

[lobello]

Much discussed issue this one. Appreciate any comments.

I let a small one bed flat out. Electric only ie no gas.

Year back I had a new CU put in with all circuits on RCD's (RCBO for lighting). Accompanied by an EICR. Registered ECA sparks did the work.

The EICR documents that the mains bonding for the water is in place (connections verified etc) and that there is "presence of supplementary bonding".

My understanding is if a. all circuits on RCD b. disconnection times met and c. mains bonding in place and all pipework linked to this continuously then no supp bonding required under 17th.

My question is would the EICR of investigated/ taken account of any requirement for supp bonding and *thoroughly* checked this ie tested continuity on pipes, ensured that any supp bonding was at least sufficient.

Two concerns I have are:

- The hot and cold pipes into the bathroom have plastic sections where the pipes come up through the concrete floor which may possibly break continuity. The *cold* pipe has two bonding cables that go back into the wall I assume these go to the light and extractor fan which were present when the flat was built. However the *hot* pipe has no bonding or cross link from the cold and comes out from under the bath to the bathroom sink where it is briefly exposed. Since the flat was built an electric shower has been added (with RCD on circuit but I suspect not bonded to any of the pipes). I guess it'd be possible to be holding the shower hose (metal) and touching said hot water pipe. Does the hot pipe in bathroom perhaps need some supp bonding or can I assume the sparky did a continuity test on it?

- In the immersion storage tank cupboard there is an overflow pipe from the plastic cold feeder tank, said pipe is initially plastic after the feeder tank but then 7 foot or so of copper running down into the floor. It isn't linked back by bonding to the mains bonding at the water in or the link across from mains in to hot water pipe at the immersion. Hence this pipe is more than likely not linked into any bonding arrangements. Does the provision of RCD's allow for this or is a link across from the other pipes required?

I could of course go back to the Sparks who fitted the CU and carried out the EICR but a. he's a tad grumpy and defensive and not that clear in any explanations b. cancelled him recently for appliance testing as he's very, very expensive and have heard no word since to say ok all cancelled c. probably already driven him mad with my concerns already! At the same time he was thorough in his EICR on other stuff and seemed more than competent.

thanks in advance.

 

[GLENNSPARK]

read what you put then in red..
where doed it mention EIC eh?

 

[lobello]

Referring to the OPs concern about continuity being broken by plastic lengths of pipe -

The purpose of bonding is not to maintain continuity and indeed plastic pipe feeding the basin copper pipes means that these copper pipes must NOT be bonded.

The cold water pipes are in exactly the same scenario (plastic pipe out of concrete floor into copper pipe) and are bonded (supplementarily I think to the extractor and light in the bathroom but for all I know one or both of the green and yellows may go back to the MET).

So if the hot pipe must NOT be bonded then surely it would follow that neither must the cold?

This also to my limited knowledge seems to contradict the 17th recommendation that to omit supp bonding in a bathroom if all pipework is effectively bonded to the MET.

A little knowledge is a dangerous thing for sure...think I have to take the advice of trust the experts judgement - one who did the EICR and the other who did the resultant CU change and accompanying EIC. Both from my understanding have a duty to check both mains and supp bonding are adequate when doing the both the inspection and notifiable work.

 

[lobello]

read what you put then in red..
where doed it mention EIC eh?

Mmmm as I pointed out I typed EICR by mistake rather than EIC, just looking through the paperwork I realised it was an EIC hence marking that up for you. The electrician who did the CU change and provided the "EIC" actually said I'd get another EICR - the two cover pretty much exactly the same ground all be it from different Regulatory bodies - ECA and NIECEC.

Thanks for your input Glenn.

 

[lobello]

read what you put then in red..
where doed it mention EIC eh?

Oh and if we're being pedantic it's does*s* and not doe*d* - ok glenn the angry "fella" ?

 

[Geoffsd]

No disrespect to you (I would not expect you to) but it is clear that you do not understand the purpose nor application of supplementary bonding.
Unfortunately, nor do a lot of 'electricians'.

The cold water pipes are in exactly the same scenario (plastic pipe out of concrete floor into copper pipe) and are bonded (supplementarily I think to the extractor and light in the bathroom but for all I know one or both of the green and yellows may go back to the MET).
So if the hot pipe must NOT be bonded then surely it would follow that neither must the cold?

From your description, that is correct.

t to omit supp bonding in a bathroom if all pipework is effectively bonded to the MET.

That's the point - it does not say 'all pipework', it says 'all extraneous conductive parts'.

Pipes that are NOT e-c-ps must NOT be bonded.

A little knowledge is a dangerous thing for sure...think I have to take the advice of trust the experts judgement - one who did the EICR and the other who did the resultant CU change and accompanying EIC. Both from my understanding have a duty to check both mains and supp bonding are adequate when doing the both the inspection and notifiable work.

I would not think the CU replacement would involve checking "supplementary bonding was adequate" as none is now required.

The EICR would report on the installation without altering anything.
From what you say it would appear that some doubts should have been raised about the supplementary bonding.

 

[lobello]

No disrespect to you (I would not expect you to) but it is clear that you do not understand the purpose nor application of supplementary bonding.
Unfortunately, nor do a lot of 'electricians'.


From your description, that is correct.


That's the point - it does not say 'all pipework', it says 'all extraneous conductive parts'.

Pipes that are NOT e-c-ps must NOT be bonded.


I would not think the CU replacement would involve checking "supplementary bonding was adequate" as none is now required.

The EICR would report on the installation without altering anything.
From what you say it would appear that some doubts should have been raised about the supplementary bonding.

No offence taken Geoff and your are correct.

The EICR and EIC have relevant boxes ticked for "Presence of supp bonding conductors".

Situation is...

Supp bonding to both hot and cold pipes and sink in the kitchen - 1 lead disappears into the wall.
Supp bonding from cold pipe in bathroom - 2 leads disappear into the wall. None on hot water pipes in bathroom.
No way of me verifying if this supp bonding goes to a. the MET or b. any or a number of the appliances within the kitchen or bathroom. Or even in the case of the bathroom cold pipe one cable could go to MET and one to the light.

Additionally no idea if the possibly short run of plastic pipe (it disappears into concrete floor) is long enough to make the pipework in the bathroom or kitchen non-extraneous or if it remains extraneous.

So many variables, what would be your advice - check back with the spark who did the EICR or the one who gave me the EIC, get another spark in. Or just trust it to have been assessed properly in the EICR.

And if no supp bonding is actually required is there any harm in there being supp bonding in the bathroom or kitchen (as detailed above) if it runs to aplliances in thos rooms rather than the MET.

Thanks

 

[Geoffsd]

Supp bonding to both hot and cold pipes and sink in the kitchen - 1 lead disappears into the wall.

Supp bonding not required in kitchens anyway.
Could the one that disappears into the wall be Main Bond from water supply?

Supp bonding from cold pipe in bathroom - 2 leads disappear into the wall. None on hot water pipes in bathroom.

If, as you said these pipes are supplied by plastic (and so NO continuity to anything else) then this 'bonding' (actually would be earthing, not bonding) should be removed.

No way of me verifying if this supp bonding goes to a. the MET or b. any or a number of the appliances within the kitchen or bathroom. Or even in the case of the bathroom cold pipe one cable could go to MET and one to the light.

Supplementary bonding should not go to the MET.
It is to connect all extraneous and exposed conductive parts in a location (bathroom) to equalise any potential difference in the event of a fault - i.e. those parts becoming live.
So, perhaps you can see why any 'isolated' parts (sink pipes supplied by plastic, door handle or even a spoon) should NOT be bonded.

Additionally no idea if the possibly short run of plastic pipe (it disappears into concrete floor) is long enough to make the pipework in the bathroom or kitchen non-extraneous or if it remains extraneous.

Can only be determined by testing as telectrix has said, although obviously any wire connections have to be disconnected.

So many variables, what would be your advice - check back with the spark who did the EICR or the one who gave me the EIC, get another spark in. Or just trust it to have been assessed properly in the EICR.

There are a lot of variables. Even without your (now) RCD protection supplementary bonding may not be necessary.
It is not a question of "metal pipe - apply bonding"
If there are any anomalies then I would not think calling the EICR one back would be wise.
Have a word with the CU installer.

And if no supp bonding is actually required is there any harm in there being supp bonding in the bathroom or kitchen (as detailed above) if it runs to aplliances in thos rooms rather than the MET.

No harm in keeping correctly applied bonding. Check 'isolated' parts.
It should not run to MET.
There was no need for it in kitchens anyway.

 

[lobello]

Supp bonding not required in kitchens anyway.
Could the one that disappears into the wall be Main Bond from water supply?

Thanks Geoff

1. Main bonding is just above the incoming water on/off in the immersion cupboard (in hall) and is 10mm. On an old test (back in the days of 16th - 2004) is listed as equipotential bonding to water mains. On recent EIC and EICR also identified as 10mm main protective bonding conductor to water.

2. The one linking the cold to hot tap and kitchen sink - which goes back into wall behind and below the sink is (according to 2004 test) listed as 4mm supplementary bonding...

3. This test from 2004 didn't see the supp bonding in the bathroom, side of bath tough to remove! But I'm fairly sure this is also 4mm. Surprising he didn't see this as he originally fitted the shower (just above the bath taps) electrics with a plumber.

4. All this bonding was I assume done when the flats were built in 1996. Nothing altered bonding wise since I bought in 1998 and fairly sure previous owner did no work. So would be similar in 120 other flats.

If, as you said these pipes are supplied by plastic (and so NO continuity to anything else) then this 'bonding' (actually would be earthing, not bonding) should be removed.

Where the pipe comes up from the concrete floor it is plastic but then copper from there to taps. Where the pipes go into floor from the immersion cupboard it's all copper. Guessing here but I think the actual pipe running under the floor is copper, the plastic was perhaps just an easy way for the original fitters to get the piping into room. Hence my original point wondering if a short run of plastic i.e. plastic bend would break the continuity back to the main bonding.

Supplementary bonding should not go to the MET.
It is to connect all extraneous and exposed conductive parts in a location (bathroom) to equalise any potential difference in the event of a fault - i.e. those parts becoming live.
So, perhaps you can see why any 'isolated' parts (sink pipes supplied by plastic, door handle or even a spoon) should NOT be bonded.

Makes sense at least for now ;-) Still given it's 4mm think it's probably connected to lights and extractor fan.

If there are any anomalies then I would not think calling the EICR one back would be wise.
Have a word with the CU installer.

CU installer - grumpy, defensive and very expensive. I may have burnt my bridges with him as booked in for appliance testing recently but a more reasonably priced decent option came up and cancelled. Not certain he'll provide answers but can try...he'd likely charge me £200 to check and remedy as well!

Guess the question now is assuming the pipes in kitchen and bathroom are connected to electrical fittings in those rooms and not the MET (as you say it ought not go back to MET and can't imagine they built 120 flats wrongly). Is there any issue with this or is it simply unnecessary.

And finally at least for now, would assume the CU installer would know if the supp bonding went to the MET as he'd have to reconnect it when fitting the new CU??? If it doesn't go to the MET it has to go to the lights or other electrics in same room right?

Thanks again.

 

[Deleted member 9648]

Lobello I think you are getting your knickers in a twist over nothing.

1.Main bonding in place and adequate.
2.All circuits RCD protected.
3.Presence of at least some supplementary bonding in the bathroom.....in practice whether it goes to the MET or more correctly to exposed conductive parts within the location it will do the same job.
4.It most likely isnt even required.
5.You have EIC's and EICR's in place which covers your ---.
6.You need to get out more.

 

[markc123]

Mmmm as I pointed out I typed EICR by mistake rather than EIC, just looking through the paperwork I realised it was an EIC hence marking that up for you. The electrician who did the CU change and provided the "EIC" actually said I'd get another EICR - the two cover pretty much exactly the same ground all be it from different Regulatory bodies - ECA and NIECEC.

Thanks for your input Glenn.

If im reading that as i think im reading that, then you're wrong lobello.

EIC and EICR are completley seperate certificates, and nothing to do with individual schemes. The EIC isn't just ECA and the EICR isn't just NICEIC.

Mark.

 

[lobello]

If im reading that as i think im reading that, then you're wrong lobello.

EIC and EICR are completley seperate certificates, and nothing to do with individual schemes. The EIC isn't just ECA and the EICR isn't just NICEIC.

Mark.

Thanks Mark yes I *now* realise they are different certificates.

You read that particular quote wrongly, I was marking up that I knew they were different certificates.Didn't phrase it well though.

My confusion caused initially by the ECA guy who fitted the new CU that he would provide a new EICR.

None the less I'd consider that fitting a new CU would necessitate checking the bonding arrangements, my understanding is any Part P notifiable work would do this regardless. Especially changing the main board, fitting RCD's and all involved in that.


Looking through the paperwork earlier I identified my mistake

 

[Geoffsd]

1. Main bonding is just above the incoming water on/off in the immersion cupboard (in hall) and is 10mm. On an old test (back in the days of 16th - 2004) is listed as equipotential bonding to water mains. On recent EIC and EICR also identified as 10mm main protective bonding conductor to water.

Correct

2. The one linking the cold to hot tap and kitchen sink - which goes back into wall behind and below the sink is (according to 2004 test) listed as 4mm supplementary bonding...

Ok - not really needed.

3. This test from 2004 didn't see the supp bonding in the bathroom, side of bath tough to remove! But I'm fairly sure this is also 4mm. Surprising he didn't see this as he originally fitted the shower (just above the bath taps) electrics with a plumber.
4. All this bonding was I assume done when the flats were built in 1996. Nothing altered bonding wise since I bought in 1998 and fairly sure previous owner did no work. So would be similar in 120 other flats.

Where the pipe comes up from the concrete floor it is plastic but then copper from there to taps. Where the pipes go into floor from the immersion cupboard it's all copper.

If you can see both ends of the copper pipes and they are not connected electrically to anything else then they should not be bonded.

Guessing here but I think the actual pipe running under the floor is copper, the plastic was perhaps just an easy way for the original fitters to get the piping into room. Hence my original point wondering if a short run of plastic i.e. plastic bend would break the continuity back to the main bonding.

It's nothing to do with breaking the continuity. It would be better if all metal parts had the continuity broken.
Supplementary bonding is applied to reduce the resistance between parts which already have continuity.

Makes sense at least for now ;-) Still given it's 4mm think it's probably connected to lights and extractor fan.

And shower when fitted.

CU installer - grumpy, defensive and very expensive. I may have burnt my bridges with him as booked in for appliance testing recently but a more reasonably priced decent option came up and cancelled. Not certain he'll provide answers but can try...he'd likely charge me £200 to check and remedy as well!

Oh well. Though, perhaps, he deserves a high price.

Guess the question now is assuming the pipes in kitchen and bathroom are connected to electrical fittings in those rooms and not the MET (as you say it ought not go back to MET and can't imagine they built 120 flats wrongly). Is there any issue with this or is it simply unnecessary.

Unnecessary in the kitchen so it doesn't matter there.
In the bathroom it should have connected all extraneous and exposed conductive parts together but not isolated parts.

In the past people tended to connect everything 'just in case' without having to think about it.

And finally at least for now, would assume the CU installer would know if the supp bonding went to the MET as he'd have to reconnect it when fitting the new CU??? If it doesn't go to the MET it has to go to the lights or other electrics in same room right?

He would have noticed it at the CU but may not have disconnected it.

 

[lobello]

Lobello I think you are getting your knickers in a twist over nothing.


5.You have EIC's and EICR's in place which covers your ---.
6.You need to get out more.

5. True but I'm over conscientious and a obsessive/profound worrier ;-0
6. Too true but in my defence I have a flu like virus right now and hence stuck indoors

 

[Geoffsd]

None the less I'd consider that fitting a new CU would necessitate checking the bonding arrangements, my understanding is any Part P notifiable work would do this regardless. Especially changing the main board, fitting RCD's and all involved in that.

That is true as far as main bonding is concerned but there isn't really much point checking that which his work will render no longer relevant.

 

[lobello]

That is true as far as main bonding is concerned but there isn't really much point checking that which his work will render no longer relevant.

Geoff your being extremely helpful thank you.

Let me see if I can get this straight so as to talk to the CU installer with minimum fuss...Is below correct..

Kitchen
Can see both ends of pipes i.e. one end into taps and one into plastic fitting at ground level.

Not necessary any longer due to RCD's

Not necessary to remove as not a bathroom and irrelevant if supp bonding here goes back to MET or to light fitting, no gain no loss.

Bathroom
As per kitchen both ends of cold pipe visible i.e. one into plastic fitting at floor and one into taps

You said - "

If you can see both ends of the copper pipes and they are not connected electrically to anything else then they should not be bonded." - the cold pipe has a joint and then pipe running into an electric shower - a dumb question but would that count as electrically connected?

Am I looking to get this supp bonding removed or connected to all exposed conductive parts or does it makes no odds and leave as is?

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