Main Bonding Question.

[brspark]

Just been to a house no bonding on gas or water. Bonded gas as enters by cu 10mm all done and sorted. Water enters property at other end of house supply is black plastic pipe with stop tap on end then house pipework has been run in plastic. Is bonding to water still required as surely earth potential is gone from water pipes.

 

[oxocube]

If the pipe coming out of the ground is plastic it doesn't need bonding. But are you absolutely sure its black plastic, because the water companies only use blue plastic.

 

[brspark]

Yes checked with householder who has lived there for many years and it was put in when the water companies removed the lead pipework. When i took hold of stop tap it moves easily definately plastic it was done in 70's.

Thanks for help

Cheers
Steve

 

[vernam616]

Is the stoptap plastic too? If not you somehow will need to get a clamp onto it

 

[telectrix]

Is the stoptap plastic too? If not you somehow will need to get a clamp onto it

why????

 

[oxocube]

Is the stoptap plastic too? If not you somehow will need to get a clamp onto it

Thats incorrect, its metallic things come from below ground that need bonding. And contrary to popular belief fresh water is not a very good conductor.

Edit - This is from an IET report,

"The ERA tests confirm that tap water in a plastic pipe is a poor conductor of

electricity. One metre of 15mm diameter of plastic pipe filled with tap water fromLeatherhead where the ERA are based, has resistance of 100,000 Ohms. This onemetre of 15mm pipe will restrict currents to less than fatal values and of course inpractice, there would be many metres of pipe between metal items of plumbing​

equipment and earth."

 

[Des 56]

If its plastic supply and copper internal,it still needs bonding,but in your case, with plastic and plastic its a joy to behold

 

[SPARTYKUS]

To be sure ( to be sure ha ha! I am IRish so can take the mick) just run the wander lead and test it like yer meant to if not sure

 

[vernam616]

I was thinking along the lines of in an event of fault, the water becomes live, homeowner gos to stop tap and gets a belt, however reading above its not the case

 

[telectrix]

water can't be "live". i know, i chucked a hair dryer in the bath and she survived.

 

[vernam616]

Haha good answer

 

[Engineer54]

Thats incorrect, its metallic things come from below ground that need bonding. And contrary to popular belief fresh water is not a very good conductor.

Edit - This is from an IET report,

"The ERA tests confirm that tap water in a plastic pipe is a poor conductor of

electricity. One metre of 15mm diameter of plastic pipe filled with tap water fromLeatherhead where the ERA are based, has resistance of 100,000 Ohms. This onemetre of 15mm pipe will restrict currents to less than fatal values and of course inpractice, there would be many metres of pipe between metal items of plumbing​

equipment and earth."

Makes you wonder why tap water is totally banned from being used on MV overhead string cleaning operations. ...lol!!!. Maybe because water conductivity varies greatly from one area to another and from one region to another. The harder the water, the more conductive it will be...

I know of an instance where homeowners in one area, (in the Midlands i think) in a new build housing development were getting more than just a tingle from taps etc, all piped in PVC and no gas on the estate. This was a fair time ago before RCDs were common place, and as a precaution, the developer ended up having to provide an up front RCD as a precautionary safety measure. Mind, this estate had quite a few problems with the electrical install on these houses. All wired with copper coated T&E wiring too as i remember....

 

[Geordie Spark]

If the pipe coming out of the ground is plastic it doesn't need bonding. But are you absolutely sure its black plastic, because the water companies only use blue plastic.

It's true that nowadays we do tend to use blue plastic (Alkathene) pipe but in the past black has been used.

 

[Knobhead]

I worked on induction furnaces where the 660V coils and cables had water pumped through them for cooling. To stop the fixed (earthed) water pipes shorting the coil two 9” sections of plastic broke the circuit. Had there been any leakage the whole system would have fried, the coil could handle up to 4000A
I did eventually have to lengthen the plastic pipes, not because of earth leakage (which we did monitor) but of all things electrolysis. It was causing the pipes to fur up.
It shows that water isn’t a particularly good conductor. The only treatment to the water was a softener and biocide.