Earth Wire for Equipotential bonding

Discussion in 'Electricians' Talk' started by Not_a_spark, Dec 4, 2006.

  1. Not_a_spark

    Not_a_spark New Member

    Can someone please advise of the size of earth wire required for equipotential bonding and where it should be correctly connected. On various sites I have seen it said take back to CU on others that it must not. On some that it can be taken through the lighting circuit earth.

    Any one out there give some clarity please. Much appreciated. Cheers
  2. JP.

    JP. Screwfix Select

    Main equipotential bonding conductors half size of main earthing conductor min 6.0mm and if PME (TNCS) 10.mm(Strapped 16mm to MET). Supplementary bonding conductors....2.5mm mechanically protected or 4.0mm if not.....most people automatically use 4.0mm....B-)
  3. JP.

    JP. Screwfix Select

    Clue (domestic enviro): - 50 metres 10.0 mm earth and 100 metres of 4.0mm earth and 5 meters of 16.0 mm earth cable please..(start of works 1st instance order)....B-)
  4. Not_a_spark

    Not_a_spark New Member

    .......if PME (TNCS)
    10.mm(Strapped 16mm to MET). Supplementary bonding


    Excuse my ignorance. What does that mean? My incoming earth to the CU looks like it is in about 6mm max (probably 4mm)
  5. unphased

    unphased Screwfix Select

    Hi

    If PME (main earth connected in to neutral of cut-out) then the main earth conductor should be minimum 16mm2 and this would be connected directly to the earth bar in the CU. Main equipotential bonds are also normally connected directly to the main earth bar in the CU. One should be connected to the gas on the installtion side within 600mm of gas meter and the other to water pipe within 600mm of stopcock.

    If there is a Main Earth Terminal (MET) near to the cut-out then sometimes you will see main bonds connected to this and just the main earth going to the CU. Either way is perfectly acceptable.

    UP
  6. Not_a_spark

    Not_a_spark New Member

    Unphased
    This is an old installation. I do not have anything near either 16mm or 10mm cable running to the CU or any of the pipework for the Gas or Water. I will certainly have another look later when I get back to it later today.

    Thanks for everyones help so far. No doubt I will be asking further questions later
  7. JP.

    JP. Screwfix Select

  8. M107

    M107 New Member

    UP dont forget it may just be one equipotential bonding conductor from MET then looped between gas/water/oil services.
  9. sinewave

    sinewave Screwfix Select

    Not a Spark,


    Sounds like you ought to Get a Spark! ;)
  10. JP.

    JP. Screwfix Select

    Not a Spark,


    Sounds like you ought to Get a Spark! ;)

    Well thats me out of the equation then....:^O
  11. Not_a_spark

    Not_a_spark New Member

    Hi

    I have uploaded some pictures for you info/amusement of my incoming supply connection (whose outer sheath looks like lead) plus the connecting earth and fusebox. Perhaps this might help you understand why everything you guys have described seems Alien. Unless of course you can advise otherwise....

    Cut and paste the links to your browser or open in a new window

    http://i96.photobucket.com/albums/l161/lmanningphotos/Elecsupply1.jpg

    http://i96.photobucket.com/albums/l161/lmanningphotos/Elecsupply2.jpg

    http://i96.photobucket.com/albums/l161/lmanningphotos/Elecsupply3.jpg

    http://i96.photobucket.com/albums/l161/lmanningphotos/Elecsupply4.jpg

    Comments welcome
  12. unphased

    unphased Screwfix Select

    Hi

    From the photos your earth system is wired as TN-S. However, the cut-out appears to be PME ready because the connection terminal on the RHS of the cut-out would be where the main earth conductor is normally connected for PME. That does not mean that you have PME though the elec board would need to confirm it. I would recommend that you get your cut-out upgraded and have a spark sort out all the earthing.

    UP
  13. Not_a_spark

    Not_a_spark New Member

    That does not mean that you have
    PME though the elec board would need to confirm it. I
    would recommend that you get your cut-out upgraded
    and have a spark sort out all the earthing.

    UP

    Thanks UP

    How would I go about getting it upgraded. Is this the elec board or would a spark do it. Any rough ideas on costing for the upgrade.

    NAS
  14. Not_a_spark

    Not_a_spark New Member

    Hi

    Anyone got any ideas for costing of the upgrade UP is talking about??

    Thanks
  15. baldy

    baldy New Member

    was told by napit assessor that main equipotential bonding should be in 16mm for PME installations. Said it was just a recommendation tho - not in the regs
  16. Lokkars Daisy

    Lokkars Daisy New Member

    was told by napit assessor that main equipotential
    bonding should be in 16mm for PME installations. Said
    it was just a recommendation tho - not in the regs

    Napit 16mm ! you do know that Napit works as a franchise,don't you ? and doesn't it show !
    I mean would you ask the Tupperware lady ,the composition of her products ?
  17. hohmslaw

    hohmslaw New Member

    baldy, 16mm is specified in electrical supply regs.
  18. baldy

    baldy New Member

    baldy, 16mm is specified in electrical supply regs.

    For main earth yes - but not for main equipotential bonding?
  19. Clark Kent

    Clark Kent New Member

    baldy, 16mm is specified in electrical supply
    regs.

    For main earth yes - but not for main equipotential
    bonding?


    Your quite right baldy..;-)
  20. footrot

    footrot New Member

    So chaps.

    What happens next year when the 17th Edition comes out?
    With Bonding? New ring main? RCD's.

    Why not wait and get it done under the new regs?

    Please, I'm only asking and it is the season of goodwill, I think.

    Cheers

Share This Page