Earthing a water pipe??

[winston1]

Wrong. A metre of water in a 15 mm pipe is not very conductive.

Try it. Get bit of plastic pipe, fill it with water and measure its resistance.

 

[bernardgreen]

I think there is no doubt that, in some situations, a solid floor (particularly of an outhouse) can qualify as an extraneous-c-p

and the lower few feet of some walls.

are surely connected by the conductive water within the pipe

there is some conductvity

fill it with water and measure its resistance.

Use at least 100 cm of copper pipe at each end of the plastic pipe as the electrodes.

Use 230 volts applied across the one metre of water, measure the current and calculate the conductivity.

Put a 230 volt filament lamp in series with the 230 supply to act as a safety "fuse".

If you are so sure that water does not conduct significant current would you be confident for any part of your body to be part of the test circuit ? DO NOT TRY IT

 

[John D v2.0]

Use at least 100 cm of copper pipe at each end of the plastic pipe as the electrodes.

Not sure what you're getting at there, this isn't like a lake where the water has loads of parallel paths (our the earth) so you want to spread them to get better conductance. The size of the path is 3.1x36 and is 1m long. The conductive end pipe at each end only needs to be a couple of cm long as the water to copper boundary isn't any less conductive than water alone.
But it does depend on your water, distilled water won't be conductive but sea water will let a little current pass. I wouldn't touch it for sea water but tap water would be much higher resistance than my body.

 

[bernardgreen]

Not sure what you're getting at there,

Test with only the pin point end of a multi-meter probe in contact with the water and the conductivity is limited by the cross-sectional area of water in contact with the probe orrespective of the cross sectional area on the water in the pipe.

 

[John D v2.0]

Test with only the pin point end of a multi-meter probe in contact with the water and the conductivity is limited by the cross-sectional area of water in contact with the probe orrespective of the cross sectional area on the water in the pipe.

Yes but there's a big different between a pin point and 100cm of copper pipe. A few cm would be ample.

the overall point I was making was about the available paths being small regardless. I'd expect in the hundreds of kilohms, andcertainly not providing an extraneous conductive part.

 

[DIYedboy]

This is very interesting..............let's say a cable near my kitchen copper pipe becomes bare and the live touches the pipe, that pipe then becomes live, but it's connected to the blue plastic incoming main, but the copper is connected to earth via the not very conductive water.................will this reduced conductive link to earth be enough to trip the breaker?

 

[EFLImpudence]

NO.

We would not need to bond water pipes if it were the case.

 

[EFLImpudence]

Anyway, if water were a good conductor it would all be at earth potential, wouldn't it?

 

[stillp]

Use at least 100 cm of copper pipe at each end of the plastic pipe as the electrodes.

Did you mean 100 mm Bernard?

 

[bernardgreen]

Did you mean 100 mm Bernard?

Yes I did, thanks for spotting my error

 

[John D v2.0]

Now it makes more sense!

 

[aptsys]

This is very interesting..............let's say a cable near my kitchen copper pipe becomes bare and the live touches the pipe, that pipe then becomes live, but it's connected to the blue plastic incoming main, but the copper is connected to earth via the not very conductive water.................will this reduced conductive link to earth be enough to trip the breaker?

That's not the purpose of bonding.

 

[DIYedboy]

Thanks Loop eeeeerrrrrrr help me out Apt................if I have a house with all copper water pipes and I attach a bonding clamp and a 10mm cable to that and the MET, surely you have just earthed all your water pipes (not that they needed it because they were already earthed by the metal pipes)

 

[Jadele]

LOL this is still going. Look up PME and read up on that. The thing that you raised though originally is not to do with that though as like you say the incomer is plastic. So now its really about earthing that piece of pipework in the kitchen or not and there are various schools of thought on that within this thread

 

[DIYedboy]

You're right Jad, but you can't knock a man for being interested in a subject and wanting to know more can ya?