Lost neutral on PME consequences

[LastManOnline]

Was round my mums building some raised beds, and on her road UKPN were putting a new supply in for a house down the road, on my way back to the car UKPN had gone home so I had a little look in the whole, someone also left the meter box open on the side of the house and it has a new PME service head, here is the joint, doesn't look to have an earth electrode to me

View attachment 84259
I also wonder how street lights are allowed on PME

I wonder if that black cable running out of the cable joint is, nt going to an earth electrode?

 

[LastManOnline]

So looking at this it seems the mitigation of using PME on a TN-C-S supply is a poor solution (almost pointless), perhaps that's why the DNOs often don't put PME electrodes in as mentioned in the video from GSH

I have been "walk checking" TNC-S supplies to "stand alone" houses in the countryside in recent times. Often a house will have its own pole mounted trafo. It's all TNC-S here so I, m really curious to know what type of earth electrode the DNO is installing. As they (pole trafo, s) are all installed on private property,I have, nt been able to get up close enough yet to inspect one. The other difficulty is that even in getting up close to inspect one, you still cannot know what kind of electrode has been installed in the ground. But bearing in mind modern houses have no alternative earth paths, it would have to be a very, very significant electrode to be of any use.

 

[marcuswareham]

I wonder if that black cable running out of the cable joint is, nt going to an earth electrode?

The black cable running out of the joint on the left of the image is the feed to the new suppy head,

I am not sure what the black cable in the middle is, it looks like it runs under the joint, but I would have thought any cables would have to come out of the ends, I think when i looked it thought the black one in the middle was a bit or PVC tape or cable tie, but it does look like a cable on the image maybe its an electrode cable

 

[marcuswareham]

I have been "walk checking" TNC-S supplies to "stand alone" houses in the countryside in recent times. Often a house will have its own pole mounted trafo. It's all TNC-S here so I, m really curious to know what type of earth electrode the DNO is installing. As they (pole trafo, s) are all installed on private property,I have, nt been able to get up close enough yet to inspect one. The other difficulty is that even in getting up close to inspect one, you still cannot know what kind of electrode has been installed in the ground. But bearing in mind modern houses have no alternative earth paths, it would have to be a very, very significant electrode to be of any use.

Interesting, my village has a transformer mounted on 2 poles, its very easy to get to as its on a public footpath, this seems to have a rod much like the ones at the bottom of the services poles, the dog keeps the resistance down by keeping it watered ?

There is another very small fenced in sub station on the sane path with a transformer of a similar size of a pole mounted one all cables to this are underground, I guess this area could have an earth mat, there is no evidence of a rod from what you can see

 

[mattg4321]

Not normally electrodes but big copper plates I've seen DNO use round here on properties with their own transformer

 

[LastManOnline]

Not normally electrodes but big copper plates I've seen DNO use round here on properties with their own transformer

I appreciate you meant to draw a distinction between an "earth rod" and a "copper plate". In principle an electrode covers any type of conductive material designed to make contact with the ground. I suspect (but cannot confirm yet) that the electrodes (whatever type) used over here in TNC-S systems are not adequate in "stand alone" electrical installations.

 

[marcuswareham]

Walked past another bit of pavement UKPN have dug up tonight

They have been repairing some cable, they have put 2 new sections of cable in with 4 joints, none of which have electrodes. There is also a smaller joint that has new TN-C-S cable on one side of the joint and an old TNS bitumen covered style cable on the otherside, I guess this was to connect a house to the new cable. Again no earth electrode and goes to show TN-S is almost always TN-C-S

 

[LastManOnline]

Again very interesting photo, s. One thing that strikes me as odd is the conversion of the supply system does not appear to be followed up in an orderly manner by informing the homeowner and posting a notice somewhere, like on the DNO, s website, confirming a significant change has taken place and that new safety measures need to be considered (open PEN sensors etc)