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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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  • Former Community Member
    0 Former Community Member

    Chris Pearson:


     


    Kelly Marie:

    In one of the recent EV charging threads there was a link to SSEs LV manual I read some of it and it looked like it said that SSE don't turn existing underground cables into PME by earthing the neutral whenever there is a a repair or extension done if I've read that right maybe DNOs are less than keen on it too. Anyone know for certain if this is the case? I bet UKPN will chirp in soon if he is still about




    I know for certain that SSE "PME'd" my service cable (and urgently too) 'cos I saw them do it. ?


     



    However, if they are going to formally declare PME on the  system, the DNO also has to ensure that relevant electrodes are in place at source end and penultimate service position branch along with a few other well defined locations along the way. They may well also need to connect the end of the distributor (the PEN) to another adjacent distributor PEN as reinforcement before they can actually state the service is PME. It's actually not as haphazard as it might seem - and DNO's wont do it unless all the prescribed electrodes are in place


    It is probably worth pointing out that even if the PEN goes AWOL, there are usually several other local consumers shunting the system so the voltage rise is usually constrained


    Regards


    OMS


     
     

Reply
  • Former Community Member
    0 Former Community Member

    Chris Pearson:


     


    Kelly Marie:

    In one of the recent EV charging threads there was a link to SSEs LV manual I read some of it and it looked like it said that SSE don't turn existing underground cables into PME by earthing the neutral whenever there is a a repair or extension done if I've read that right maybe DNOs are less than keen on it too. Anyone know for certain if this is the case? I bet UKPN will chirp in soon if he is still about




    I know for certain that SSE "PME'd" my service cable (and urgently too) 'cos I saw them do it. ?


     



    However, if they are going to formally declare PME on the  system, the DNO also has to ensure that relevant electrodes are in place at source end and penultimate service position branch along with a few other well defined locations along the way. They may well also need to connect the end of the distributor (the PEN) to another adjacent distributor PEN as reinforcement before they can actually state the service is PME. It's actually not as haphazard as it might seem - and DNO's wont do it unless all the prescribed electrodes are in place


    It is probably worth pointing out that even if the PEN goes AWOL, there are usually several other local consumers shunting the system so the voltage rise is usually constrained


    Regards


    OMS


     
     

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