Main bonding to Alkathene water pipe.

[Shakey]

Grae, the OSG isnt out yet! Or do you mean the 16th edition version which is no longer valid, I had my OSG delivered last week by amozon,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

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

 

[PAUL M]

thanks Paul, If you check the date of my post, it was.....well......before the OSG came out

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

oops its a been a long hard day

 

[Spudmiester]

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.

 

[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

 

[Shakey]

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

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"

good discussion though!

 

[jimes]

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

 

[DYCHE4230]

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.

 

[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??

 

[DYCHE4230]

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)