The Ultimate PME/TNS Exportation! B-)

Discussion in 'Electricians' Talk' started by sinewave, Mar 25, 2007.

  1. Clark Kent

    Clark Kent New Member

    The long and winding road
    That leads to your shed
    Will never disappear
    Ive seen that road before
    It always leads me there
    Lead me to you shed

    The wild and windy pme
    That the rain washed away
    Has left a pool of indecision
    Trying for the day
    Why leave me standing here
    Let me know the way

    Many times Ive been lost
    And many times Ive lost
    Any way you'll never know
    The many ways Ive tried

    But still they lead me back
    To the long winding pme
    You left me standing here
    A long long time ago
    Dont leave me waiting here
    Lead me to your shed

    But still they lead me back
    To the long winding road
    You left me standing here
    A long long time ago
    Dont leave me waiting here
    Lead me to your shed
     
  2. X

    X New Member

    ?

    Ahh.. there is one tiny difference

    No matter which way its argued... the buck would stop with the person who designed / did the export.

    Hense.. I never export PME as PME
     
  3. Lokkars Daisy

    Lokkars Daisy New Member

    Well as there would appear to be no serious considered reason why you shouldn't and a very good reason why you should (LOW Ze) I can not understand why you wouldn't?

    Lets have a hand count Rabbit and X against ,any others ?
     
  4. X

    X New Member

    no serious considered reason

    Tut tut LD

    Leading the witnesses..

    I belive that a case has been made that makes a very serious concideration... and that is accountability

    Untill there is a reg that must be obeyed... instead of differing guidence (the meaning of which can be applied after the event)
     
  5. JP.

    JP. Screwfix Select

    Thats put the lid on it for me..no exportation of PME tied down or whatever..funny how a few people outside of the Forum have said to me that the exportation of PME proper is a no no..and even more definitely a no no with regards to livestock..however thats not trashing Sine as he of all people would have a very good reason to post that topic and it must be correct..will stick with my own known ways though..no more input from me.
     
  6. DandMElectrical

    DandMElectrical New Member

    Concerning the lost neutral, if there was no load on it and no path to a phase conductor and being as it is tapped to earth at the local transformer, would it suddenly become 230v.....or not ?

    It would be like isolating a supply conpletely and then touching the neutral.

    I guess the load could flow from an adjacent property, through you, to earth but if a voltage always chooses the path of lowest resistance would it not make sense that it would flow through the sub main cable rather than a person.

    Can somebody test voltage between an isolated incoming neutral and an earth spike of low impedence today ?

    Where's a TT system when i need one. lol
     
  7. DandMElectrical

    DandMElectrical New Member

    Would it be at 230v potential to phase, yes - obviously, would it be at 230v potential to earth though thats the question.

    Being as the earth is always separated from the phase conductor by insulation........
     
  8. X

    X New Member

    would it be at 230v potential to earth
    though thats the question.

    Being as the earth is always separated from the phase
    conductor by insulation........


    Phase (R1) connects through any load to rn back to the cut out, then has nowhere to go other than than via R2.

    The cpc and any class 1 equipment is now @ 230 (ish)..
     
  9. wally2

    wally2 New Member

    X & wally & the odd few = no
    200+ = yes
    If we were in court & the jury were all pme types we would be doomed
     
  10. X

    X New Member

    You got it in a nut shell wally2

    But...

    Doing our way, there can never be any doom
     
  11. Lokkars Daisy

    Lokkars Daisy New Member

    Well I am taken aback at the peeps on here who find fault in using a pme supply to supply an outbuilding!?

    I posted on the subject so as to explore the reasons why some people considered it dangerous, not to debate whether it was allowed or not.

    Of course it is allowed and has been for many years, carried out to BS7671 EEBADS and all that there is no more danger from a PME supply used to supply an outbuilding that there is from the pme supply at source.
    Probably safer in many cases as you get an excellent earth supplied.

    What is the problem , nobody has actually stated the precise danger.

    JP ( and TWIMC) whats all this about never using pme ,and No NOs from people you have spoken to ?

    Isn't it enough that the IEE have endorsed the the use of pme for a remote building .....
    here..... http://www.iee.org/Publish/WireRegs/WiringMatters/Documents/Issue16/2005_16_autumn_wiring_matters_electrical_installationsoutdoors.pdf

    Just what is the problem , ANYONE?
     
  12. JP.

    JP. Screwfix Select

    LD I wish you a very good evening mate..sort it out..:) I for one will be sticking with what I know..however one small point (might be of interest to you)..A long time back on a job we had a new 3 phase PME sub main put in by the DNO (flat conversions job) and on that job the DNO asked if I would incorporate earth pit which I did as for me that was highly sensible..however they did not stipulate that I had to do this only asked. In a nutshell sunk earth pit and run 16mm to TP DB MET through ducting cable was in..so certainly in this case the DNO supply was well tied down and I for one would never worry about lost neutrals in this instance and probably would never worry about it anyway due to the amount of tying down on the DNO network..however all the exporting stuff to sheds etc..dissimilar earthing..good luck mate..:)
     
  13. Lokkars Daisy

    Lokkars Daisy New Member

    Good evening to you JP ,I wonder why the dno asked you to put in an earth pit?

    Ok then JP
    A main house with pme supply , you decide to build a small granny flat say 30 meters away , the loading was so little you decided to supply the granny flat from the main house. Would you be happy running a 4 core swa to the flat , live,neutral and earth from main house pme supply to flat,
    If not happy then why ?
     
  14. wklivesvtime

    wklivesvtime New Member

    there is no problem ld. I will still be running a earth core in my swa. Imagine having to tt every outside supply, apart from making the installaton less safe the cost!!! This differing true earths is just theory speculation giving a reason to make our job harder with no real substance to back the waffle. Its not even exporting pme your just extending your supply as normal. Add bonding where required, use rcd and job done. Sines origional post suggested a rcd was not req as you were exporting pme hence still the house equi zone - that is pushing it a bit. But tt every garage ect.... have fun. No offence to anyone choosing to tt just my 2p, you can all laugh whan i am doing a stretch cos someone has got 20v across them from different earth values due to varying resistivity :)
     
  15. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Is there a difference between exporting PME earth to shed, and the PME system in your house that is essentially a PME system exported from the transformer to your house ?


    Mr. HandyAndy - really
     
  16. X

    X New Member

    Is there a difference

    One is an equipotential zone ... The other may not be.
     
  17. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Is there a difference

    One is an equipotential zone ... The other may not be.


    You mean the house is, but the shed might not be ?


    But if all things are bonded at the shed(just like a house is) then the shed is an equipotential zone in it's own right, isn't it ?


    The house has ONE main point of earth(or is supposed to have)to which everything is fed back to, and the shed will have one point of earth(the incoming exported earth), to which everything at the shed would be fed back to. And ne'er the twain shall meet, nor will.

    So you have two completely separate(but linked by a long cable) equipotential zones.


    Safe as houses, innit ?


    Mr. HandyAndy - really
     
  18. Clark Kent

    Clark Kent New Member

    I like that Andy..



    ;)
     
  19. Lokkars Daisy

    Lokkars Daisy New Member

    Is there a difference

    One is an equipotential zone ... The other may not be.



    You mean the house is, but the shed might not be ?


    It could just as easily be the other way around !
     
  20. Clark Kent

    Clark Kent New Member

    Yes...


    Perhaps the Beatles 'Lond and winding PME' is apt..



    :)
     

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