Unearthed lighting circuit

Discussion in 'Electricians' Talk' started by solo man, Jan 31, 2004.

  1. solo man

    solo man New Member

    A mate has installed several metal walllights in his living room.There is no earth on the lighting circuit.He does not want his walls "chopping".Is there any way to overcome this problem which does not include a rewire.
     
  2. The Trician

    The Trician New Member

    In a nutshell, no! You need to have all metal fittings properly earthed, so it looks like its time to get the hammer & chisel out. Sorry:(
     
  3. Deelow

    Deelow New Member

    Depends on the wall construction! Is the wall solid? Sometimes a small hole at the top, a slot over a stud and a little backfilling will do the trick in a non-solid wall!
     
  4. Fubar

    Fubar New Member

    There is no earth on the lighting
    circuit.

    Solo,

    Sounds really obvious, but are you absolutely certain there is no earth wire? I've seen the earth cut off right inside the PVC sheath on may occasions. If there is enough cable behind the light, you may be able to strip up a little further to find the earth.

    Only problem with this is that the person that installed the circuit has probably done the same at every rose/junction box too, so restoring the earth back to the consumer unit may be very time consuming.

    --
    Michael
     
  5. GrahamB

    GrahamB New Member

    If the downleads to the wall-lights are in conduit (unlikely) you could try feeding a single earth wire down, which means lifting floorboards upstairs. But you would then still have the job of linking up all the earths back to the CU, or perhaps pick up an earth on an upstairs power point, if this is permitted by the Regs?
     
  6. finjon

    finjon New Member

    It's easier to change the lights. You could use lv wall lights. LV trafos generally don't require earths.
     
  7. The Trician

    The Trician New Member

    It's easier to change the lights. You could use lv
    wall lights. LV trafos generally don't require earths.

    NO, but the supply cables do! Even if there is no earthing termianl on the tx.
     
  8. Damocles

    Damocles New Member

    um, if youre in a bathroom, isnt one of the reasons for having low voltage that it just went through a transformer and is no longer referenced to earth?
     
  9. The Trician

    The Trician New Member

    Yes, but the 240v supply cable to the primary side of tx will still need an earth, even if it is just terninated into a block connector. That way, if there is a short between L+E the fault current will disconnect the circuit?
     
  10. sparky

    sparky New Member

    sorry,but you have to rewire or run the risk of shock.you could suggest a double insulated wall light?
     
  11. finjon

    finjon New Member

    I've just fitted about 20 lv lights. The trafos come flexed, in 2-core. No earth.
     
  12. The Trician

    The Trician New Member

    If I remember correctly, the initial poster asked if the absence of an earth/cpc to each of his mains metal wall lights was ok or not? He then went on to state that he was not keen about having to chase out his walls to install new cables complete with the requisite cpcs.

    Regardless of either mains or transformer, the fact remains that he will still need to chase out the wall to bury the cables? I confess that my product knowledge is weak when it comes to the different types of LV lighting in today's marketplace but all the ones I have seen have very short tails from and to the TX. Surely it must be cheaper in the long run just to dig out and replace his existing cables? Or do you bury the transformer in the plaster too:)
    I'm pretty certain that all 'fixed wiring' must have a cpc to meet the regs?
     
  13. finjon

    finjon New Member

    Yes, I think the regs now require an earth at every switch and light, in a new installation. But, when you haven't got one, you do the best with what you're faced with. If you have a metal fitting which says it must be earthed, and you haven't got an earth, you shouldn't use it. If the fitting requires earthing, it must be earthed. Really, whatever about lv lights , it would be easier and more economical, to replace the lights, than the wiring. If the 240V connection of a lv fitting comes within the housing of a metal fitting, an earth is essential. However,(regs aside), an earth at a light which doesn't require one, serves no purpose.
     
  14. finjon

    finjon New Member

    Sorry, I ownly mentioned low voltage because it has been my (recent) experience that they don't require earths. The trafos tend to be double insulated. (I confess it's a bit of a red-herring to the question).
     
  15. The Trician

    The Trician New Member

    Hey Finjon, you from Dubiln too? God Bless the Ould country!
     

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