Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 68 replies
  • Subscribers 32 subscribers
  • Views 9386 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

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?
Parents
  • 0

    perspicacious:
    In North Norfolk, where a whole village is upgraded from bare overheads to A.B.C. overheads, U.K.P.N. supplies a white sticky label that is affixed on the main cutout. On it is hand written the Zs value after testing. That is very helpful.


    Wouldn't Ze be more helpful?


    Regards


    BOD




    Indeed Ze is a better description. I believe that the U.K.P.N. labels do say Ze as opposed to Zs. But thinking about the TN-C-S system having solid conductors in the supply I used Zs as it included the length of supply cable that may run in a cottage loft for a few metres before being connected to a main cut out, so is not totally literally physically external, but may be regs wise. Some old buildings have overhead incoming positions on the first floor but the consumer unit and main cut out can be several meters away for convenience. I suppose the reading of earth fault loop impedance will be the same if we call it Ze or Zs if the test is carried out at the main cut out in a property. I am not referring to final circuit tests though.


    Z.

Reply
  • 0

    perspicacious:
    In North Norfolk, where a whole village is upgraded from bare overheads to A.B.C. overheads, U.K.P.N. supplies a white sticky label that is affixed on the main cutout. On it is hand written the Zs value after testing. That is very helpful.


    Wouldn't Ze be more helpful?


    Regards


    BOD




    Indeed Ze is a better description. I believe that the U.K.P.N. labels do say Ze as opposed to Zs. But thinking about the TN-C-S system having solid conductors in the supply I used Zs as it included the length of supply cable that may run in a cottage loft for a few metres before being connected to a main cut out, so is not totally literally physically external, but may be regs wise. Some old buildings have overhead incoming positions on the first floor but the consumer unit and main cut out can be several meters away for convenience. I suppose the reading of earth fault loop impedance will be the same if we call it Ze or Zs if the test is carried out at the main cut out in a property. I am not referring to final circuit tests though.


    Z.

Children
No Data

Community Rules & Guidelines