High Impedance Earth, advice

[ban-all-sheds]

M=2 is adequate for PME

Got a metal water supply pipe?

 

[JohnW2]

M=2 is adequate for PME

Got a metal water supply pipe?

As I think you know, in the case of my installation, that question opens up a can of worms.

Yes, I currently have a metal water supply pipe, and that appears to be connected to my neighbour's PME earth - hence the sub-0.3Ω ZDB I enjoy (when measured with bonding is in place). That fact obviously goes a fair way to negating the point in my 'declining' the PME earth I have been offered!

However, there seems to be a potential problem with that supply pipe (over which some joker seemingly built my other neighbour's house!), so it's probably going to be replaced fairly soon. Since the replacement will presumably be plastic, everything might well then change.

Kind Regards, John

 

[Mr Chibs]

To the OP

I recently had a quote for PME earthing, as my house had none... it was £175.

 

[JohnW2]

To the OP ... I recently had a quote for PME earthing, as my house had none... it was £175.

I think that they commonly do it for nothing, not the least because the need for it is often due to their failure to adequately maintain a TN-S earth!

Kind Regards, John

 

[Mr Chibs]

Interestingly the DNO chap said there was rumour that at the start of next year, these types of works would all be free.
Fortunately I didn't pay, but only because their was corroded main coming in and needed to be corrected.

 

[John D v2.0]

Ukpn policy is to convert where changes are made to the cable with permission, but to supply TN-S if the householder wants to retain it. I assume that's for free.

 

[John D v2.0]

won't lose one's earth completely

Yes but why do we need an earth in the first place? Just for the outside tap problem. Having an earth is only a means to an end (not getting an electric shock off the actual ground or vice versa), not an end in its own right.

 

[ban-all-sheds]

I currently have a metal water supply pipe, and that appears to be connected to my neighbour's PME earth

M=3 then.

 

[JohnW2]

M=3 then.

Yep, at least - but, as I said, that number could well reduce in the foreseeable future.

Kind Regards, John

 

[JohnW2]

Yes but why do we need an earth in the first place? Just for the outside tap problem. Having an earth is only a means to an end (not getting an electric shock off the actual ground or vice versa), not an end in its own right.

If one could be absolutely certain that the building was, and would always remain, totally earth-free, then I think that that would be true (within the building's equipotential zone - so other than for outside taps etc.). However, that certainty probably never exists - for a start, as bernard is always reminding us, 'unbonded' wet/damp floors and walls can sometimes provide a path to earth.

Kind Regards, John

 

[Lareon]

https://imgur.com/a/stKBj

here are the images as requested, it's quite tight under there so some are a bit close. i can take more though

 

[ban-all-sheds]

No sign in those photos of an earth cable to the CU.

What wazzock did this?:

 

[Lareon]

the 16mm earth goes up behind the consumer unit and in.

the flex cable is a great touch i know. whoever did it obviously knew the earth was ****

 

[JohnW2]

the 16mm earth goes up behind the consumer unit and in.

Are you saying that that green/yellow cable coming from the pipe at the bottom (and disappearing behind the board) is 'the' (only) earth?

Kind Regards, John

 

[Lareon]

Are you saying that that green/yellow cable coming from the pipe at the bottom (and disappearing behind the board) is 'the' (only) earth?

Kind Regards, John

yep that's all I can see