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THE CAMPAIGN FOR REAL EARTHING

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?
Parents
  • Interestingly John I have a suggestion which would probably make this TN-S system little more expensive. In fact we are only interested in faults in earthed properties via the DNO cables, not on the network. This means that the earth core needs a fairly small cross section, and the substation has a "grown up" sized earth fault relay which isolates the HV if the earth fault current becomes enough to cause a cable failure. This would be reasonably cheap and simple, so why not? Suggesting that when the whole network is rewired, and this is certainly what is needed for this "all electric future" adding a few percent to the cable price is not much of a problem, particularly as the civils cost will be much more than the cables.
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  • Interestingly John I have a suggestion which would probably make this TN-S system little more expensive. In fact we are only interested in faults in earthed properties via the DNO cables, not on the network. This means that the earth core needs a fairly small cross section, and the substation has a "grown up" sized earth fault relay which isolates the HV if the earth fault current becomes enough to cause a cable failure. This would be reasonably cheap and simple, so why not? Suggesting that when the whole network is rewired, and this is certainly what is needed for this "all electric future" adding a few percent to the cable price is not much of a problem, particularly as the civils cost will be much more than the cables.
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