Discuss Main bonding to Alkathene water pipe. in the Industrial Electrician Talk area at ElectriciansForums.net

U

U Jay

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I wonder if someone could shed some light on the question of bonding a water main that is alkathene up to the point of entry to the building. The house is a new build and the copper pipe is not bonded. I would imagine that this is because it was not considered an extraneous conductive as there is no path to earth, but I have come accross an argument that suggests it should be bonded and would appreciate if someone could clarify. It is discussed in the following link but doesn't really answer the question.
Q & A of the Day - Main equipotential bonding and plastic services – is bonding required? - Voltimum UK - Electrical Installation Products and Contracting

Thanks,

U.
 
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G

Grae79

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  • #2
has to be bonded...only exception is if incoming is plastic and customers install is plastique too...check out page 25 of OSG :)
 
S

Shakey

  • Thread Starter Thread Starter
  • #3
has to be bonded...only exception is if incoming is plastic and customers install is plastique too...check out page 25 of OSG :)
Grae, the OSG isnt out yet! Or do you mean the 16th edition version which is no longer valid?

I dont agree anyway. 'Extraneous conductive path' is a precise definition.

i read the article in the link - 'internal copper pipework may be incontact with earth' - what a crock! Where? How?

They did, hwever correctly focus on the role of the designer. If i went to a job with plastic incoming, and presuming the bathroom is not in the garden and no internal pipework was in contact with earth - then there would be no extraneous conductive paths, and i, as the deisgner' would not bond.

To do so would intriduce a path to earth where there would not have been one, thus introducing a fault path and hazard
 
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Grae79

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  • #4
Grae, the OSG isnt out yet! Or do you mean the 16th edition version which is no longer valid?
Really? must've missed that. :eek:

Until the 17th osg comes out in couple of mths i'll stick with the 16th version regarding this issue. It may make me a bad boy and i'm not advising anyone else to do it and i understand ur argument about extraneous conductive paths etc etc etc etc.
 
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4

4x4 mark

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  • #5
i have done a lot of new builds in the last few years and as the price of copper has gone up the plumbers use of copper pipe has gone down, but most plumbers still use a small amount of copper under the kitchen sink(usual water entry point) so you can still bond to this or failing that get the plumber to put you a short length of copper in so you can bond that bit. the house should fail its nhbc if it has no bond on the water and gas.
 
U

U Jay

  • Thread Starter Thread Starter
  • #6
Thanks for the replies, the gas is correctly bonded and I think a lot of the house is piped in plastic with the a bit of copper as mentioned, under the sink where the water enters the property. I assumed the ommission was due to the points Shakey outlined above and as the CU is in very close proximity to the water main there is no other reason why they didn't just chuck in a bit of bonding so to me it appears a definite decision not to bond. This house is brand new with a massive NICEIC sticker on the front of the CU so I'm once again assuming it was all done to their rulebook! Perhaps the owner should bring it up with the developer while they are still snagging, but the question is, am I breaking regs by leaving it as it is and carrying out some work?
Cheers
U
 
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ian.settle1

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Mentor
Arms
Thanks for the replies, the gas is correctly bonded and I think a lot of the house is piped in plastic with the a bit of copper as mentioned, under the sink where the water enters the property. I assumed the ommission was due to the points Shakey outlined above and as the CU is in very close proximity to the water main there is no other reason why they didn't just chuck in a bit of bonding so to me it appears a definite decision not to bond. This house is brand new with a massive NICEIC sticker on the front of the CU so I'm once again assuming it was all done to their rulebook! Perhaps the owner should bring it up with the developer while they are still snagging, but the question is, am I breaking regs by leaving it as it is and carrying out some work?
Cheers
U
If the house is brand new and developer is still snagging, I would not touch it until all the defects have been done by the original electrical contractors.
 
D

DYCHE4230

  • Thread Starter Thread Starter
  • #8
I dont agree anyway. 'Extraneous conductive path' is a precise definition.

i read the article in the link - 'internal copper pipework may be incontact with earth' - what a crock! Where? How?

They did, hwever correctly focus on the role of the designer. If i went to a job with plastic incoming, and presuming the bathroom is not in the garden and no internal pipework was in contact with earth - then there would be no extraneous conductive paths, and i, as the deisgner' would not bond.

To do so would intriduce a path to earth where there would not have been one, thus introducing a fault path and hazard[/quote]



I've done a CU change for my Elecsa registration this friday and for the reasons Shakey has mentioned above did not bond the water incomer. However the CU change was done to 16th edition and the osg says if part of the installation is metal then it should be bonded...I am now in a quandry cos I can't get back to bond it...Does anyone think I will fail because of this?? ps It wasn't bonded in the first place.....
 
S

sparkyork

when i ve come across this regardless of plastic coming into the house and plastic going everywhere else inside the house, ive always insisted (if there on the 1st fix) that the plumber installs a piece of copper for me to bond too.

unsure what nic will think of it as well too be honest, the new osg is out now, id have a look in that or give niccy a bell.
 
D

DYCHE4230

  • Thread Starter Thread Starter
  • #10
Funnily enough the new osg changes its perspective on this from insisting to bonding to only recommending it...and if you can prove that the copper pipe is not extraneous then it seems that the osg leaves it upto you.
 
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Shakey

  • Thread Starter Thread Starter
  • #11
when i ve come across this regardless of plastic coming into the house and plastic going everywhere else inside the house, ive always insisted (if there on the 1st fix) that the plumber installs a piece of copper for me to bond too.

unsure what nic will think of it as well too be honest, the new osg is out now, id have a look in that or give niccy a bell.
Rich, this utterly confuses me:confused:

What's the point of bonding to a bit of copper? the only thing that will be bonded is.......well......the bit of copper!:eek:

To clarify, from the 17th OSG

"4.4 Main protecive bonding of plastic services:

There is no requirement to main bond an incoming service where the incoming service pipe and the pipework within the installation are both of plastic.

Where there is a plastic incoming service and a metal service installation withing the premises, main bonding is recommended unless it has been confirmed that any metal pipework within the building is not introducing an earth potential"

So back to my original point, unless the metal pipework goes out into the garden, a quick insulation check from the metalpipework to the MET will prove it is not an extraneous conductive path, and no bonding is REQUIRED.;):)
 
S

sparkyork

see your point shakey, im often just overkill on stuff and just worry about metal towel rails and things like that! allthough it says in the regs its not required under certain conditions id still be tempted to put on in.

may seem a daft question but its it possible that the water within the pipework could have a potential??
 
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Shakey

  • Thread Starter Thread Starter
  • #13
see your point shakey, im often just overkill on stuff and just worry about metal towel rails and things like that! allthough it says in the regs its not required under certain conditions id still be tempted to put on in.

may seem a daft question but its it possible that the water within the pipework could have a potential??
Not a daft question at all Rich, this has been well researched and documented.

Obvioulsy the resistance of the water will vary, pure water is an isolator (its why we deionize water to use in batteries), and dirty water can conduct, the water in your pipes lies somewhere between the two.

The measured value is around 20k ohms per metre for standing water in a pipe, flowing water would be much higher.

So what I think you actually mean is, will the water in the plastic pipe turn it into an extraneous conductive path?

And the answer, for normal conditions, is no:)
 
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PAUL M

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  • #14
Grae, the OSG isnt out yet! Or do you mean the 16th edition version which is no longer valid,:D I had my OSG delivered last week by amozon,;)
 
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spark-doctor

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  • #15
Grae, the OSG isnt out yet! Or do you mean the 16th edition version which is no longer valid,:D I had my OSG delivered last week by amozon,;)
Look at the date when Shakey posted. It was 2 months ago:D
 
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Shakey

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  • #16
Grae, the OSG isnt out yet! Or do you mean the 16th edition version which is no longer valid,:D I had my OSG delivered last week by amozon,;)
thanks Paul, If you check the date of my post, it was.....well......before the OSG came out:p

Got my new one as well now - only spent the last three days with head in it updating the EAL Domestic Installers course:eek::(:(
 
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Spudmiester

  • Thread Starter Thread Starter
  • #18
Not a daft question at all Rich, this has been well researched and documented.

Obvioulsy the resistance of the water will vary, pure water is an isolator (its why we deionize water to use in batteries), and dirty water can conduct, the water in your pipes lies somewhere between the two.

The measured value is around 20k ohms per metre for standing water in a pipe, flowing water would be much higher.

So what I think you actually mean is, will the water in the plastic pipe turn it into an extraneous conductive path?

And the answer, for normal conditions, is no:)

As Shakey says, water can conduct under certain conditions. I know as I got a proper Plymouth Rock off some water out of all things, a saftey shower on a chemical plant. So yes, it can and does !
I went and got the trusty testers, one probe to earth, one probe in water flow, and hey presto 240V. Bloody hell.
 
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sparkyork

thats why i if it was my own house id bond it anyway, everything else is under fault conditions this and that etc, so under certain fault conditions id be dead!!

know its not the same thing but its like relying on an rcd to protect you when you may have a reading of 1667 ohms, i will still maintain a good proper ZS reading and not rely on anything to work all the time
 
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Shakey

  • Thread Starter Thread Starter
  • #20
thats why i if it was my own house id bond it anyway, everything else is under fault conditions this and that etc, so under certain fault conditions id be dead!!

know its not the same thing but its like relying on an rcd to protect you when you may have a reading of 1667 ohms, i will still maintain a good proper ZS reading and not rely on anything to work all the time
I can see your point Rich, buth the other side of the coin is that you may be INTRODUCING a path to earth where there wasnt one before

I use to do a lot of equipment/electronic type work on a test bench.

We used to have insulated mats, and the entire workstation was entirely insulated within arms reach from any potential earth path. The last thing we wanted was a parth to earth there!

Its a fine line, if an exposed conductive part went live under fault conditions and there was no extraneous paths to touch........

in the 15th, everything was bonded (main as well as supplementary) then in the 16th just supplementary in bathrooms (I am focussing on domestic) now there is no requirement for supplementary for most installations

the wheel turns, and it will no doubt turn again:rolleyes:

there's still old school sparks who insist on bonding kitchen radiators and sinks, then running a cable back to the MET "just in case":eek:

good discussion though!:)
 
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J

jimes

  • Thread Starter Thread Starter
  • #21
osg is out i looked at my mates today!...copper pipe of installation could be screwed to wall of house with copper/brass saddles or concreted into floor in places introducing an earth and also if gas is bonded and all pippework goes through a metal bulkhead of a boiler then there maybe an earth path
 
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DYCHE4230

  • Thread Starter Thread Starter
  • #22
Ok...had my elecsa assessment today and brought up the issue of bonding water pipes...Assessor told us to do IR between copper pipe and an earth point(cpc in socket outlet in this case) reading was 0.07Mohms. If the reading is greater than 0.02Mohms(22000ohms) then the pipe is not an extraneous condutive part and does not need bonding.
 
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sparkyork

thats still a prety low reading tho isnt it! if you got that across line and neutral you'd be thinknig its near enough continuous if you know what i mean! lol

i knoiw the regs are the regs but??
 
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DYCHE4230

  • Thread Starter Thread Starter
  • #24
yeah I agree it is a low reading and if I had done the test beforehand and got that reading I would have thought it was extraneous...But he did quote where the figures came from ( i kind of wasn't listening at this point, just glad i did n't have to bond) :)
 

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