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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> bonding of plastic then to copper https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1096922134 Message started by supra59 on Oct 4^th, 2004, 9:35pm

Title: bonding of plastic then to copper
Post by supra59 on Oct 4^th, 2004, 9:35pm

hi lads a little unsure on whether to bond water pipes as the incoming pipe is plastic then goes to copper, i think i have read something like its now considered more dangerious to bond plastic pipes than not any thoughts on this or have i been dreaming

� � �thanks supra

Title: Re: bonding of plastic then to copper
Post by tellondon on Oct 4^th, 2004, 9:50pm

There is absolutely no point in bonding plasic pipes they dont conduct electricity

Title: Re: bonding of plastic then to copper
Post by plugwash on Oct 4^th, 2004, 10:07pm

sure the question is what about the now very common situation where the pipe from the street is blue MPDE but the house piping is copper

now obviously it can't bring in a potential from the ground

but the thing is water pipes are a large network of copper through the house and could easilly cary a nasty potential round the house

also having the only earth to the pipework system being the thin earth wires from the cuircuits feeding the bathroom seems wrong to me it goes against the if its earthed it shoudl be earthed well principle

Title: Re: bonding of plastic then to copper
Post by supra59 on Oct 4^th, 2004, 10:53pm

tellondon i am aware of plastic not conducting
electric but im also aware all the other piping in the property does.

pugwash not that it matters but its a commercial property and all the copper piping is new as its just being refurbed so there is no bonding at all

thanks for your moments

Title: Re: bonding of plastic then to copper
Post by L.Spark on Oct 4^th, 2004, 11:50pm

What did I miss lol, I think the simple Answer your looking for is this - bond the copper pipe after any connections, no need to bond plastic.

Why on earth someone couldnt have just told you that god only knows ::)

Good evening to you!.

Title: Re: bonding of plastic then to copper
Post by supra59 on Oct 5^th, 2004, 11:21pm

thanks L Spark i have just found the document i had glanced at and ,if i would of read on it goes into more detail this is what i was reading

Everyone knows that water and electricity do not
mix, that the risk of electric shock is greater when
there is water around. They know that the risk and
severity of an electric shock is increased as a result
of the presence of water. This may be the reason
for the concern that water in plastic pipes may
conduct electricity and that bonding is required.
Because of this, the IEE commissioned the
Electrical Research Association to carry out
measurements of the electrical conductivity of
water in plastic pipes.

Thanks again for your promt answer Supra

Title: Re: bonding of plastic then to copper
Post by L.Spark on Oct 6^th, 2004, 5:07am

Nah it's no problem, I've read them all before Supra, they will go on about this scenario and that, but the end result is the same, �I just summerised what you needed to know to give you an awnser �:)

The tests that you were talking about there were to really find out how good a conductor water was, and it came back poor, thats not to say water is safe, it's certainly not, it just has a high resistance.

it's more an issue of the copper pipes you have to worry about.

Title: Re: bonding of plastic then to copper
Post by plugwash on Oct 6^th, 2004, 8:00am

the major danger from water and electricity is the fact it lowers the skin resistiance dramatically

also it can go down gaps in fittings and deliver a shock that way though the small cross sectional area of the gaps should keep the actual shock small (it was a fairly minor shock when i tried washing a plugged in extention lead some time ago)

Title: Re: bonding of plastic then to copper
Post by L.Spark on Oct 6^th, 2004, 8:25am

LOL, I thought you was too ashamed to talk about that one ;)

yep water has a high resistance, hence if you have a bit of moisture around a switch you may get a tingle.

Title: Re: bonding of plastic then to copper
Post by ban-all-sheds on Oct 12^th, 2004, 6:03pm

wrote on Oct 4^th, 2004, 11:50pm:

Maybe because it's wrong? Part of the definition of extraneous-conductive-parts includes the ability to introduce a potential, generally an earth potential.

If the incoming water pipe is plastic then it cannot introduce a potential, and the copper pipes thereafter need bonding just as much as metal curtain tracks do....

Title: Re: bonding of plastic then to copper
Post by Beanzy on Oct 12^th, 2004, 8:26pm

B-A-S is spot on re; introducing an earth potential from outside. But the issue of Main_Eq_Bonding still remains problematic if there's enough volume of copper or interconnected metal to allow it to function as an 'earth'. This is what's meant when people talk of systems being 'earthy' ( I know it's stupid term, but it's what they use) The risk comes from touching the ever mentioned metal which has become live due to fault conditions, while simultaneously touching something else at earth potential. So if there is a large enough volume of copper (dunno how much either) or if it's making a good connection to earth somewhere in the system, then you could have a better path to earth through the victim, so zap. so by bonding anyway if not all copper you avoid this risk, and the faff of working out if it's enough copper in the system to act as an earth.

Gawd I hate plumbing, just had a right pain int the rear of a main bond to oil & water do today. How come they only get the spark in after the kitchen's been done by the bodgers?

Title: Re: bonding of plastic then to copper
Post by L.Spark on Oct 12^th, 2004, 9:01pm

wrote on Oct 12^th, 2004, 6:03pm:

Maybe because it's wrong? � Part of the definition of extraneous-conductive-parts includes the ability to introduce a potential, generally an earth potential.

If the incoming water pipe is plastic then it cannot introduce a potential, and the copper pipes thereafter need bonding just as much as metal curtain tracks do....

Then you have misread what I said, bonding of copper and not of plastic in the house..

Title: Re: bonding of plastic then to copper
Post by ban-all-sheds on Oct 14^th, 2004, 1:57am

No - you've misread what I said.

You: "bond the copper pipe after any connections"

Me: "If the incoming water pipe is plastic then it cannot introduce a potential, and the copper pipes thereafter need bonding just as much as metal curtain tracks do.... "

Title: Re: bonding of plastic then to copper
Post by L.Spark on Oct 14^th, 2004, 3:40pm

well whatever, im pretty sure we both have the same idea