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Topic Title: More Earthing I'm Afraid.
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Created On: 05 April 2013 12:07 PM
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 05 April 2013 12:07 PM
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Bluesmeister

Posts: 14
Joined: 05 April 2013

Hi All.

We carried out a Periodic Inspection Report in 2006 on a domestic property. The result or our result was recorded as satisfactory.

Water pipe was bonded with a 10mm at the incoming point.

All the hot & Cold water pipes in the Airing cupboard were bonded together, BUT no bond took back to the MET or consumer.

They have recently had further works carried out and the resulting certification report states that no supplementary earth bonding exists within the property.

They do however acknowledge that bonding of the pipework has been cross bonded but that it doesn't go anywhere!!

My thoughts are that all is well, but we now have a conflict.

Thoughts anyone please.

Thank You
 05 April 2013 12:16 PM
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AJJewsbury

Posts: 12620
Joined: 13 August 2003

That'll be bonding rather than earthing then

It sounds to me like there is some supplementary bonding there, but it's not complete - as it doesn't include c.p.c. of circuits within the bathroom. That was acceptable under the 15th and early 16th as long as there were no exposed-conductive-parts, but isn't up to later standards.

- Andy.
 05 April 2013 12:24 PM
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Bluesmeister

Posts: 14
Joined: 05 April 2013

Thank you Andy.

There is only a light in the bathroom, they are telling the client that a dedicated supplementary earth bonding conductor should be connected between the airing cupboard/bathroom and the consumer unit/MET.

To my mind it is, albeit carried out by the copper water pipes within the property. BTW, it is all copper pipes (old school), with no plastic push on connectors etc.

Thanks

Blu.
 05 April 2013 12:40 PM
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AJJewsbury

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they are telling the client that a dedicated supplementary earth bonding conductor should be connected between the airing cupboard/bathroom and the consumer unit/MET.

Well that's bollox. The whole point of supplementary bonding for a bathroom is to create a local equipotential zone to minimise potential differences within the bathroom - adding unnecessary conductors to different potentials (e.g. the MET) will tend to drag one corner of that zone down, so increasing the potential differences. Not only is adding such a conductor pointless, it could actually make things (slightly) worse.

What they're describing is extending the main bonding - that would only be necessary if an extraneous-conductive-part entered the properly through the bathroom.

- Andy.
 05 April 2013 01:13 PM
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Bluesmeister

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That is also my understanding and I did in fact tell them something very similar.

I am not sure if they believed me but there is nothing I can do about that now, as they have given out the "re-testing" of the installation out to the people that have fitted out the new bathroom.

Ah well it is Friday.
 05 April 2013 01:19 PM
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daveparry1

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Yes, there are people out there that think supplementary bonding needs to go back to the met!

Dave.
 05 April 2013 01:22 PM
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mikejumper

Posts: 1934
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Originally posted by: Bluesmeister
My thoughts are that all is well, but we now have a conflict.
Thoughts anyone please.

You're right.
 05 April 2013 01:37 PM
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Jaymack

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Originally posted by: Bluesmeister
they are telling the client that a dedicated supplementary earth bonding conductor should be connected between the airing cupboard/bathroom and the consumer unit/MET.

That is one for the client to make a complaint on "they" to their registering authority, if pertinent! I doubt that any qualified electrician would require earthing of a bond, a plumber perhaps, but then they have some weird methods. I also suggest that an apology is forthcoming from both parties involved. Reference to this thread is a possibility!

The ESC have a pamphlet on their site, copies are also available for issue to clients: -

"Why do earthing and bonding need to be checked?" There's no mention of earth bonding!

Regards
 05 April 2013 01:37 PM
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Parsley

Posts: 1236
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Originally posted by: AJJewsbury

they are telling the client that a dedicated supplementary earth bonding conductor should be connected between the airing cupboard/bathroom and the consumer unit/MET.


Well that's bollox. The whole point of supplementary bonding for a bathroom is to create a local equipotential zone to minimise potential differences within the bathroom - adding unnecessary conductors to different potentials (e.g. the MET) will tend to drag one corner of that zone down, so increasing the potential differences. Not only is adding such a conductor pointless, it could actually make things (slightly) worse.



What they're describing is extending the main bonding - that would only be necessary if an extraneous-conductive-part entered the properly through the bathroom.



- Andy.


Great answer Andy

See snag 32 of NIC's earthing and bonding snags and solutions book.

Regards
 05 April 2013 01:49 PM
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Jaymack

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Originally posted by: Bluesmeister
All the hot & Cold water pipes in the Airing cupboard were bonded together,

They do however acknowledge that bonding of the pipework has been cross bonded but that it doesn't go anywhere!!


This bonding is seen very often and is hopefully only carried out by plumbers, it seems to be part of their training. Decorating pipes under sinks and at boilers like a Christmas tree, is not required in the wiring regulations. Earthing Yes, as well as main bonding to service pipes etc., and equipotential bonding in bathrooms etc.. The latter is not so much of an issue nowadays if ADS is relevant, main bonding is in place and there is overall RCD protection, but then you knew that.

Regards
 05 April 2013 02:26 PM
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MAXMIRA

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This goes back to 2006, which version of the standards was the original test carried out to
 05 April 2013 02:58 PM
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AJJewsbury

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This goes back to 2006, which version of the standards was the original test carried out to

In 2006 the 16th + AMD 1 + AMD 2 would have been current. From memory the supplementary bonding requirements was pretty much as it is now (without the omission if RCDd etc option) - but I'd have to check that.
- Andy.
 07 April 2013 01:49 AM
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jimmyoneball

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The answer is simple to me. Measure the resistance from the bathroom light cpc to the hot water pipe (to include any cross bonding & connection clamps) and if it is less than 0.05 Ohms then suplementary bonding isn't required.
 07 April 2013 12:18 PM
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geoffsd

Posts: 563
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It doesn't have to be that low.
0.05 is generally regarded as negligible so it is unlikely it could ever be that low.

R ≤ 50 / Ia (or I∆n for RCD)
 07 April 2013 06:09 PM
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Zs

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Joined: 20 July 2006

...and 0.05 is a number that was made up around a table at a meeting in London some years ago...From the horse's mouth to Zs in 2012.

Bluesmeister (best forum name in the universe apart from RocknRoll which makes it a tie-break situation), welcome to the forum. You are right.

Perhaps ask the other party, gently, to show you where they got their information from? I expect it will go quiet.

Any gas in there?

Zs
 07 April 2013 06:49 PM
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Martynduerden

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Originally posted by: Zs


Any gas in there?
Zs


Gas - Yeah a lot of hot air, and some gasses from the rear...

-------------------------
Regards

Martyn.

Only a mediocre person is always at their best
 07 April 2013 10:35 PM
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OldSparky

Posts: 600
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Originally posted by: Bluesmeister

Thank you Andy.



There is only a light in the bathroom, they are telling the client that a dedicated supplementary earth bonding conductor should be connected between the airing cupboard/bathroom and the consumer unit/MET.





To my mind it is, albeit carried out by the copper water pipes within the property. BTW, it is all copper pipes (old school), with no plastic push on connectors etc.



Thanks



Blu.


god this ***** me off... i used to work with a bloke who always took a 10mm from the bath to the consumer unit.. what an idiot
 08 April 2013 05:46 AM
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ebee

Posts: 5943
Joined: 02 December 2004

I`ve seen that done a lot on shower installs over the years.
It minds me that the installer might be thinking upon the following lines perhaps.
"No bonding in house. OK I`ll install the shower and I will at least main bond the bathroom pipework although not the house pipework, this way my install will comply, at least in spirit and leave the remainder no worse and possibly much safer than it was".

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
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