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THE CAMPAIGN FOR REAL EARTHING

John Peckham
I think that we were considering adopting PME earthing systems today on what we know now we would say no thanks?


I strongly believe that the use of PME earthing systems is inherently unsafe. I am keen to hear any technical arguments to defend the use of PME?


Most PME DNO new distribution cable use 3 core Wavecon cables for UG distribution with single phase concentric cables tapped off for single phase users. For overhead open wire supplies of newer installs ABC cable.


There is no reason not to use 4 core Wavecons and distribute a much safer TN-S earthing system other than the cables will be a 1/3rd more expensive.


 I believe that the DNOs having been tentatively asking government  for a £trillion pounds to upgrade their networks for when we stop burning fossil fuels and go all electric. No doubt the DNOs hope that the government, civil servants and politicians will have forgotten that these private companies purchased a public assets for a knock down price with the idea that the public would no longer have to subsidies a public body! 


A good start would be that no new supplies will be PME, no replacement cables will be PME and no repairs to cables will be PME conversions. For instance a new housing estate would have to be an all TN-S installation. I understand that WPD are already installing TN-S earthing systems for new housing estates. If this is the case then well done WPD. Can anyone confirm this?


I am also concerned about the degradation of the of the Global Earthing System with use of all plastic covered cables, no bonding to metallic service pipes and the failure on DNO contractors to install earth rods and joints to save time and money. Will we start to see 442 type over voltages?


Look at my EV charging thread and the measures we are having to deploy due to PME earthing, we are having to do this because the PME system is inherently unsafe!


Is there support for my proposed campaign?
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    RichardCS2:




    AJJewsbury:


    But at least the loop impedance is kept low with a MEN system - even if it might drift a bit above local earth potential. With a fully TT system if the consumer's electrode is just in dry dust you might loose all ADS as well as having leakage currents raise the voltage on the earthing system.


    Of course if the ground really is that dry that you can't get a good connection to it even with a foundation earth or buried tape then it also implies that the risk of shock to earth is low. If you can't manage to earth a great big electrode then a couple of bare feet won't be very well earthed either.


     




    But don't forget that Skippy the Bush Kangaroo is nosing up to the earth electrode in the rain in the garden. Or that little Crocodile Dundee Jnr., also in the rain, is recovering his football barefoot on the lawn.


    Z.

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    yes - but then when it rains, and the shock risk is higher again, the ADS also works.

    Yes, OZ expect new earth rods to have the tops insulated, and actually we are also encouraged to put the tops of our earth rods in pit boxes, which has a similar effect in that it reduces the accessible voltage during fault. (I know no-one does)


    The isolated shearing station with Kylie Mingue (you should be so lucky...),  may have even more of a problem as it may well have a single phase or split phase LV, fed by single wire earth return HV, so the HV earth is carrying the HV current for normal  loads too.

    An intro to SWER  for the non-believers. Very effective, but scary.


    and a demonstration of the concept at 120v by a young man who wears goggles, when I'd be happier if he wore gloves  on youtube  here

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    mapj1:

    yes - but then when it rains, and the shock risk is higher again, the ADS also works.

    Yes, OZ expect new earth rods to have the tops insulated, and actually we are also encouraged to put the tops of our earth rods in pit boxes, which has a similar effect in that it reduces the accessible voltage during fault. (I know no-one does)


    The isolated shearing station with Kylie Mingue (you should be so lucky...),  may have even more of a problem as it may well have a single phase or split phase LV, fed by single wire earth return HV, so the HV earth is carrying the HV current for normal  loads too.

    An intro to SWER  for the non-believers. Very effective, but scary.


    and a demonstration of the concept at 120v by a young man who wears goggles, when I'd be happier if he wore gloves  on youtube  here

     




    S.W.E.R.


    U.F.E.R.


    SHED.


    Googles guy. No gloves nor calculator.


    BONK

     -ERS.


    Just run a twin and earth cable from the house.


    Edit. Goggles guy should, for greater effectiveness, have performed his experiment in the dark when it was raining.


    Z.

  • Former Community Member
    0 Former Community Member

    Zoomup:

    Just run a twin and earth cable from the house.






    Well there's always this: https://ludens.cl/paradise/turbine/turbine.html DIY 2 kV transmission line with homebuilt transformers starts about 2/3 of the way down the page. 2 pole 1.5 mm^2, 10 kVA, 600 metres back to the house. Voltage drop works out as about 3.5%.

  • 0

    RichardCS2:




    Zoomup:

    Just run a twin and earth cable from the house.






    Well there's always this: https://ludens.cl/paradise/turbine/turbine.html DIY 2 kV transmission line with homebuilt transformers starts about 2/3 of the way down the page. 2 pole 1.5 mm^2, 10 kVA, 600 metres back to the house. Voltage drop works out as about 3.5%.


     




    Thanks for that Richard,


                                             the microhydroplant is very impressive and has been very well designed and constructed. I will look at every photo carefully later when I can concentrate. Presently I am partly viewing The Big Bang Theory.


    I have seen a similar  larger working system at Inverie in Scotland that powers the whole village. There is no grid power there. The hydro system is powered by water from a very high mountain loch through a pipe that runs down a mountainside, so has high flow rate.


    Thanks,


    Z.



                                              

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    mapj1:


    and a demonstration of the concept at 120v by a young man who wears goggles, when I'd be happier if he wore gloves  on youtube  here

     




    That’s a very scary extension lead.


    Andy 

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    Very scary good job was only 110 volt supply
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    Sparkingchip:




    mapj1:


    and a demonstration of the concept at 120v by a young man who wears goggles, when I'd be happier if he wore gloves  on youtube  here

     




    That’s a very scary extension lead.


    Andy 


     




    Yes very scary....and... if he had an extension lead why did he want a S.W.E.R. system anyway? Illogical at the very least.


    Z.

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    It is not that dangerous -I have done a rather better controlled version of that experiment myself.

    That said,  for touching the rod, I'd be happier if he was wearing gloves, as yes the rod is live to the full 110V when he does his loop test and gets an amp and a bit. However, if he were to stick his meter probes into the soil around the rod, it would show that most of the voltage drop is within a few feet of the centre,  this idea that you can pull up the ground potential of a large surface area is a myth in normal soil with sensible size electrodes.

    (also why we often fence off the electrode area to keep livestock away.)
  • 0
    I meant being able to push a single pin of the plug into the trailing socket with the other pin hanging down the side at mains potential.


    Andy Betteridge

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