Advice on Earth Bonding Please

[vwed]

I'm not an electrician but would appreciate any advice on the issue described below.
I'm completely renovating my kitchen. The water supply from the street ran in an old lead pipe under the front door, under the hallway (concrete) under the kitchen floor (also concrete) and emerged on the back kitchen wall where the stopcock and rising main were situated.
Over time the flow was getting less and less, so I guessed there was a blockage forming somewhere in the narrow bore of the lead pipe. I took a punt and dug a hole halfway down the hallway, found the lead pipe, curved it round so it was know under the adjacent sittingroom floor and connected a copper pipe run to it. This copper run now comes through into the kitchen above floor level, as it will be hidden by new units and the new stop cock/rising main is below where the new sink will go. The flow is now fine so I must have bypassed the blockage.
All the joints on the new copper pipe run were done with Speedfit plastic fittings.
My understanding is that I don't have to earth bond the sink,pipes etc in the kitchen.
However looking at assorted forums I see that I should have bonding from the CU to the water supply pipe. There is bonding to the incoming gas pipe.
So where do I bond to from the CU? - the nearest bit of copper pipe on my run, even though within 500mm there is a plastic Speedfit fitting? Do I have to link up all the copper on this run up to the stop cock in the kitchen?
Thank you.

 

[truckster]

Good question, I would run the bonding cable to your side of the new stop cock so any pipe work in the house is bonded. Although you have effectively isolated the supply pipe from earth the household pipe work may still pick up an earth potential if it passes through wall etc.

Could be differing views here

 

[GLENNSPARK]

As far as i know its 6oomm from the service on the consumers side. Couldn`t you bond across the speedfits with clamps and 10mm?

 

[RogertheBodger]

Yes, interesting one, my opinion would be to bond it on the copper side of the lead/copper joint that you made, that would make it as close as it is possible to get to the point of entry (assuming the lead pipe is buried in concrete)

 

[itg]

Hmm interesting one this.
If I've read this correctly, you currently have a length on supply pipe (at mains pressure) WITHIN your house, fitted with speedfit connections, with no method of turing it off should a pipe/joint break. If this happens you will have mains pressure water all over your living room floorspace.
If it was me, I'd get a stopcock on the pipe wherever it 'enters' the house, i.e. emerges from the concrete. Make a trap door in the floor or something if you need to.

Then I'd bond to this stopcock and leave the rest as internal pipework.

If you leave it as it is then you should still bond as the On-Site Guide says that even if a water supply is completely plastic; if the majority of the internal pipework is copper then it reccommends that there should be a main bonding to the C.U.

Don't forget to add the "Safety Electrical Connection" plate at the stopcock. There is no need to bond across the plastic joints as you are no longer bonding to the earthing functionality of the supply pipe.

 

[Blowcat]

Your very brave playing with lead pipe, I would recommend replacing the whole pipe with new back to the stop cock in the street or where ever.... However I would bond the incoming water service at your main stop cock. In a perfect world within 600mm or as near to that as you can before any other pipes branch off it.

 

[yellowvanman]

Before bonding under the sink you need to determine whether its extraneous or not. Previously it was because the lead pipe was in contact with earth, now you've put in plastic joints so it may not be extraneous anymore, in which case you don't need to bond it!

You can test whether its extraneous or not by doing an insulation test between your main earth and the pipework if resistance is less than 25Kohm then its extraneous and needs bonding ortherwise it doesn't! As you're not an electrician you may need to find one to test this!

Extraneous means its a non electrical item that is bringing in an earth potential to the building.

 

[vwed]

Thanks for the suggestions guys.
Really I suppose because of all the plastic Speedfit connections up to the new stop cock in the kitchen (and beyond it for that matter) earthing to the CU will be a gesture really, although I suppose it will help earthing the CU itself back down the lead pipe?