Supplementary bonding required with RCD's? | Page 3 | on ElectriciansForums

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L

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.
 
Last edited by a moderator:
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
No - NOT 'Not necessary any longer due to RCD's' - Should NOT be bonded.
Bonding such isolated parts introduces a hazard.

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.
No (I didn't realise the kitchen had plastic supply as well) The bonding should be removed.
It's just that supplementary bonding is never required in a kitchen but this actually creates a hazard.

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

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?

That is a matter for interpretation.
If you or electrician think that the pipe entering the shower is an exposed conductive part and/or may become live by coming into contact with the shower's line conductor (in whatever circumstance) then the pipe should be earthed in the shower - to operate the mcb should this happen.


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?
It should be removed from any isolated parts.
These parts are not isolated at the moment because of the wrongly applied bonding.

 
To be honest, I'm not sure.

Even when the water is supplied in plastic the regs say to still bond on consumers side of stop-cock.
I suspect the regs haven't caught up with plastic gas supplies yet.

If both water and gas were supplied to your house in plastic and all pipes in the house were >500MΩ to MET would you want to connect them?

I know the pipes would still be connected to appliance CPCs and it would not apply so maybe continuing with main bonding is a way of ensuring there is some bonding.


The pipes in this thread, though, were not the supply pipes but short lengths between plastic and taps.
 
lobello you obviously have a lot of time on your hands at the moment so if you would like a bit of background reading have a look in the "17th edition fact sheet`s" thread at Fact Sheets 4 and 5. They cover Extraneous-conductive parts and Locations containing a bath or shower. Enjoy!

- - - Updated - - -

lobello you obviously have a lot of time on your hands at the moment so if you would like a bit of background reading have a look in the "17th edition fact sheet`s" thread at Fact Sheets 4 and 5. They cover Extraneous-conductive parts and Locations containing a bath or shower. Enjoy!
 

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