bonding in an outhouse

Discussion in 'Electricians' Talk' started by markysparky, May 31, 2006.

  1. markysparky

    markysparky New Member

    Doing an outhouse conversion at the minute and I was just wondering about the bonding arrangements.

    Both the main house and newly installed outhouse are both TT systems with the oil storage tank bonded to the main house MET.

    However the newly converted outhouse is having an oil fired combi installed and it too will have a oil supply from the main source as the house.

    Question is. Do I bond the oil coming into the outhouse too? bearing in mind this will then link the earthing arrangements of the main house and the outhouse and turn the main oil bond into a secondary MET, or should I leave it alone as it is already bonded with the house MET.

    Gotta go! chow for now :)
     
  2. Home Farm

    Home Farm New Member

    If its TT then bond everything and drop an auxiliary rod near the conversion.

    You can't have too many rods on a TT system.
     
  3. X

    X New Member

    should I leave it alone as it is already bonded with the house MET.

    Yes, I belive thats the best plan.

    Oil and gas pipes shouldn't be used as 'a secondary MET'
     
  4. Home Farm

    Home Farm New Member

    should I leave it alone as it is already bonded with
    the house MET.

    Yes, I belive thats the best plan.

    Oil and gas pipes shouldn't be used as 'a secondary
    MET'


    Sorry I disagree.

    There will be a number of parallel earth paths due to power supplies to heating pumps etc.

    Much safer to bond it properly and sink an auxiliary rod at the outhouse end then you are certain that the whole system is EEBADS.

    The whole point of bonding a pipe coming into a property is to prevent faults being imported from outside.

    If you depend on incidental earth paths the consequences are unpredictable.
     
  5. X

    X New Member

    The whole point of bonding a pipe coming into a property is to prevent faults being imported from outside.

    I rather thought it was more to prevent potential differences occuring inside, with all other benefits being secondary.

    If a gas or oil pipe is 'bonded' at its extreme points to two seperate "Earths" then there could be a suitation where there is a pd.

    Water pipe, conduit, trunking .. ok but not gas / oil.
     
  6. markysparky

    markysparky New Member

    > If a gas or oil pipe is 'bonded' at its extreme
    points to two seperate "Earths" then there could be a
    suitation where there is a pd.


    Which is excatly what's happened. Just back from the job now and found that.....

    ZE 37 ohms
    ZS 15.4 ohms

    Clearly the oil bond is causing the differance in potiental here!
     
  7. X

    X New Member

    Hahahahahahahaha

    Hmmmmmm....

    Get sinking the rods or salting the ground ... (even though Ze is ok... it needs to be more ok to be lower than Zoil)
     
  8. markysparky

    markysparky New Member

    Looks like that's the only way!

    Which means all my testing will have been a waste of time meaning I'm gonna have to do 'em all over again as well as try and get another rod in.

    FUUUUUUUUUUUUUCCCCCCCCCCCCCCCK!! :'(
     
  9. X

    X New Member

    Well... first

    Apply a bit of cunning and see if the issue can be made to go away.
     
  10. markysparky

    markysparky New Member

    Tell me more Mr X ;)
     
  11. X

    X New Member

    No...

    But it revolves on the type / size and route of the oil pipe
     
  12. markysparky

    markysparky New Member

    Will lowering the ZE of the outhouse help the situation?

    As the potiental of the house will also drop due to the bond of the oil linking the 2 buildings?
     
  13. X

    X New Member

    I meant

    But it revolves on the type / size and route of the oil pipe

    Being the existing main pipe and not the link
     
  14. markysparky

    markysparky New Member

    Dunno where your coming from X. but the only way I can see to do it is to break the copper connection with a plastic coupler.

    hmmmm......... b0ll0x! :(
     
  15. X

    X New Member

    Well.......

    Plastic is allowed but only when underground ...

    But I see your on the right wavelength
     
  16. unphased

    unphased Screwfix Select

    Bondage in the outhouse would be more likely eh? eh? ;)
     
  17. markysparky

    markysparky New Member

    Would it make it any differance if the oil pipe enters the property buried in the wall behind the skirting board which then goes straight through the length of the property to the boiler which is situated outside?. Therefore not exposed in the property at all!

    Think I know the answer but I'm desperate and grabbing at straws here!
     
  18. sinewave

    sinewave Screwfix Select

    Pengu has a point!

    We have a Oil Boiler and it's just been re-piped.

    The new feed is in plastic insulated copper pipe! ;)
     
  19. markysparky

    markysparky New Member

    Right I gotcha ............ I think!

    Naughty..... very naughty ;)
     
  20. sparkin!

    sparkin! New Member

    WHY NOT LET THE TWO EARTHING ARRANGEMENTS MERGE?:)
     

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