bonding

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paul b b

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hi chaps,

i looked at a job and the guy has no bondings on his main water, i told him he needs it ( the plumber told him he did not as the pipe in the ground was plastic). there is a mass of pipes in the cupboard, shall i just bond everything as i have no idea what is what.

thanks

paul

 
At one time Wakefield Council electricians were instructed to bond plastic pipes in bathrooms - they were told to do this incase the pipes were replaced with copper-

Intersting a number of years ago the IEE researched the resitance of water in plastic pipes and the results were astonishing, it tuned out that water is not a very good conductor in plastic pipes (having an avergae resitance of 100,00 ohms /m).

Bonding everything is not always a good idea, If the installation is insulated from the genearl mass. Then introducing the earth from an electrical system is counter-safe.

 
The plumber is wrong! If the pipes in the property are metal they should have a main bonding conductor connected to the consumer's pipes as close as practicable to the point of entry (ie just after the main stop tap) before any branches in the pipes and after the meter (if fitted).

Of course plastic pipes do not require bonding.

See section 544 of BS7671:2008, (pages 134-135) & section 4 of the OSG (pages 27-32)

 
I did a new house a few months back. All pipeworrk was plastic apart from pipes in airing cupboard and gas pipes. I was told not to bond any apart from gas. Personally I think they should be bonded as if they do become live you will get a nasty belt of them. If you had a tiled kitchen or bathroom and the pipes where to come live and they where not bonded the outcome could be fatal.

Batty

 
what about suplementry bonding?

the pipes in the bath room are a ****** to get to, well almost out of reach behind t&g. should i rip up a floor board and bond there?

thanks chaps

 
Just looking at this thread, it beggars belief that anyone should consider bonding onto plastic, let alone mention it.

The Boys

 
you bond the side inside the house....

now if its fed by plastic pipe, then it probably cant introduce a potential from the inlet, but chances are its in contact with ground under the floorboard somewhere (you know what plumbers are like), and so it could, and will need bonded. or if you really dont want to bond it, you can check if it is extraneous or not

 
Everyone appears to forget there is a simple but effective method for determining if a pipe requires supplementary bonding or does not, and that is a continuity test.

It is a requirement with corgi, now gas safe, to make the last meter of pipes feeding a boiler to be in copper. The gas pipe will always be in copper anyway.

The boiler housing and the manifold will always be connected to earth via the outlet and connected directly to the met, via the circuit cpc.

At one time plastic water supply pipes where terminated in the house with a 6" length of copper, just so electricians could have some where to bond to. This practice is now fading out, because to bond to any platic pipe over a determined length could raise the potential higher than what was there in the first place.

So if your in doubt as to bond or not then just do a continuity test.

 
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