Plastic Water main with copper throughout.

spark 68 · Mar 8, 2015

Re: Plastic Water main with coper throughout.

David Marshall said:
Just put one in cover your back as water still conducts and you dont know how far the plastic main goes I'm obviously using my immagination here but at least it has a MPC anyway the water my be connected to a gas combi or something. I would not dwell on this issue just put one in

No you shouldn't "just bond" without testing and a proper assessment, you may introduce a hazard where none previously existed.

Essex_ · Mar 8, 2015

Re: Plastic Water main with coper throughout.

davesparks said:
If the results of your test on the water main have been affected by the main bond to the gas then you have not carried out the test correctly.

Isolate the installation, then disconnect the earthing conductor from the MET (or remove test link). You then test between the incoming earth and the suspected extraneous part.

I'm not surprised you have been accused of trying to get work by unscrupulous means, a plastic water main which feeds surface clipped installation pipework is unlikely to be extraneous.

That was really good advice until the last paragraph. No need for that and ruined the thread IMO.

Geordie Spark · Mar 8, 2015

Re: Plastic Water main with coper throughout.

davesparks said:
Water alone is non-conductive, impure water such as that which is supplied by the public water mains has limited conductivity.
As far as I know the volume of water in a 600mm length of 22mm plastic pipe has sufficient resistance as to be considered an insulator at 250V

Finally somebody has grasped it!!

GB.Kayak · Mar 8, 2015

Re: Plastic Water main with coper throughout.

rattlehead85 said:
Was called to a job yesterday where a company had completed an EICR on a house fed via a plastic water main with internal plumbing done completely in copper. They had put a c2 observation code for a lack of main protective bonding to the water. The customer had shown me the EIC cert she had been given by the original company who had completed a rewire on her property.
Disconnecting the earthing conductor at the intake position and completing an IR test to the internal stopcock on the water gave me a reading of 0 megohms. To me this has indicated that somewhere within this installation the copper pipework is earthy and deemed extraneous and does warrant a main bond. I did think this could be gaining a reading through the boiler gas connection (which is bonded) I am leaning on the side of advising the client to get the original contractor back to sort this. Opinions on this before doing so would be appreciated.

Why are you carrying out an IR test when you should be measuring the continuity or otherwise of the various components in the system? Surely IR testing serves one purpose only; a proof test of the insulation in a circuit?

Leesparkykent · Mar 8, 2015

Re: Plastic Water main with coper throughout.

GB.Kayak said:
Why are you carrying out an IR test when you should be measuring the continuity or otherwise of the various components in the system? Surely IR testing serves one purpose only; a proof test of the insulation in a circuit?

https://m.youtube.com/watch?v=v38PfIVy2rI

watch this it'll explain it.