equipotential bonding request

[17thman]

Hi guys,

Some advice please. 3 months ago i finished the wiring for 60 bathrooms for a housing association, i was sub contracted. I ran 10mm t and e for new shower with isolator on a 40A rcbo. came of lighting circuit for timed extractor and fused spur for low voltage wet room shower drain pump. The incoming water supply for the buiding (on three floors) came over head through top lofts, in 25mm mdpe in each flat. I bonded in 10mm at the point it changed to copper and because the hot water and central heating came in from a common boiler, i bonded to these services too and back to the individual mets. All connections are accessible behind a service hatch built into the 'shower wall' boarding. For certification i tested continuity of bonding and completed certificates.

Now someone has done a continuity test from copper pipe work entering cold water tap to met and there is no continuity. This is because after a word with the plumbers there are some inaccessible plastic push fit plumbing connections.

The housing association want me to go back and bridge these!!!. Advice please.

Surely, the copper now holds no earth potential and if it does touch the hot or heating flow or return i have bonded these.

Ben.

 

[PrenticeBoyofDerry]

You should have bonded where the cold water supply enters the property, not at boiler hot water.
This should be done within the first 600mm of entry point.

 

[17thman]

HI prentice, my post does explain that i bonded the cold water feed as it changed to copper from mdpe as it entered each flat and that i also bonded hot water and c'h flow and return as it was a common boiler

 

[PrenticeBoyofDerry]

What distance was the mdpe from entering the house? and what do you mean by common boiler?

 

[17thman]

there are 60 flats in a housing assocaiation building on 3 floors with a boliler oom serviving hot water and central heating in copper pipe work

 

[PrenticeBoyofDerry]

so you have bonded gas at entry
you have bonded water supply at the point it changed from plastic to copper
and bonded common pipework at entry.
If so I can't see what else you could have done.

 

[electronicsuk]

It sounds to me like you did the right thing - you installed PEBs to all metallic services entering the properly, including CW main and the HW and CH supply pipework from the boiler house. I think now you'll have to fall back on the big red book and perform the tests described in there to determine whether supplementary bonding was/is necessary in the bathroom.

In any case, there is certainly no requirement to run an earth from any pipework in the bathroom back to the MET unless the pipework is an extraneous conductive part, which it doesn't seem to be from your description. There may turn out to be a requirement for SEBs as per above, but certainly you shouldn't be earthing any pipework in the bathroom as the housing association seem to be suggesting.

 

[17thman]

thank you, me neither. I think i should track down the electrician who reported this and speak to him

 

[17thman]

thanks mathew, all circuits rcd protected