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Discuss I'm not sure if the Regs allowed separately bare earths. in the Electrical Forum area at ElectrciansForums.co.uk.

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  1. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    I've been on this job to do an inspection before fitting a new RCD OR RCBO board. In most of my career until now the CPC is inside the T+E cable. This property has a separate CPC all through out the building. Only where there has been modifications, modern wiring has been used. If I can prove the ZS is good, is it ok to connect to this system. It's seems to be mainly the lighting that is wired in single sheathed cable which has been ran in conduit. I am hoping if anyone has any information regarding the regs about separate bare earth running through the property. There is a risk of borrowed neutrals if changing to an rcd or rcbo board. The customer does not want a Rewire but wants spots fitted and sockets moving. I have convinced him to change the board, now I am worried about nuisance tripping. However if you could advice about the earth mainly would be a great help. Personally I feel the wiring was good for it's day.

    IMG_20181017_102010958.jpg
     
  2. Andy78
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    Andy78 Respected Member

    Location:
    Kingston upon Hull
    Where does the earth originate ? In my experience separate bare cpcs like this are often connected to lead water pipes as a means of earthing.
     
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  3. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    Sticking my neck out here I’d say of course Because regs are not retrospective as long as all the tests are good and you comply with the current regs regarding RCDs etc I don’t really see it as any different to connecting to Red and black PVC.
     
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    Last edited: Oct 17, 2018
  4. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    Never actually seen that but good point. As long as the earth does actually come from the CU/fusebox and not the water pipe and all of the tests are ok I don’t see a problem.

    Obviously upgrading the bonding as well when replacing the board
     
  5. Andy78
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    Andy78 Respected Member

    Location:
    Kingston upon Hull
    Seen it most where rubber twin (no cpc) was used, either VIR twin or TRS. Bare cpc was often taken from a lead pipe, either soldered on or clamped on, and taken individually to sockets.
     
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  6. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    It appears to be connected to the earth on the board which is fed by TN-S
     
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  7. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    I’d be looking to just confirm that but I really don’t think there’s a problem...
     
  8. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    Found this in the ceiling also was interfering just with my continuity test, traced the wire back to this . 1mm cable connected and two lead cables of 2.5. It was a stressful day lifting floor boards.

    IMG_20181017_100309007.jpg
     
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  9. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    Is that the guts of an old thorn 8ft brings me back to the first few months of my apprenticeship taking down these old lumps and replacing them with 6fts and I mean lumps just about a 2 man lift to get the bloody thing down:screamcat:
     
  10. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    Because there are bare earthed in the board I have come to that conclusion, but to no for sure, there are so many limitations
     
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  11. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    Are the main gas and water bonded?
     
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  12. 7029 dave
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    7029 dave Forum Mentor

    Location:
    bedfordshire
    Time gone by, bare earth was used for bonding services, and used as main earth lead.
     
  13. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    Well, this is under the upstairs floor board and two cables come out, they felt cold and are metal, never seen anything like it. These metal cables go to the end of a roof end, loft. (It is a bungalow) they end up in junction boxes that go nowhere else. Diconnected
     
  14. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    I’d disconnect the bonding and the bare earths from the board and do an R2 on the bare earth from the end at the board to ensure its complete and then again at the bit your going to connect into and to the board itself and then the pipes themselves just to rule out that the bare earth was coming from elsewhere I reckon if you do that you’ve pretty much proved beyond reasonable doubt that the earth is suitable and actually coming from the CU and not the pipes or anywhere else.
     
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  15. MFS Electrical
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    MFS Electrical Forum Mentor

    Location:
    Scotland, Inverclyde, Greenock
    Business Name:
    MFS Electrical
    Old lead cables probably wonderful stuff :rolleyes: the rest of the cables in the house aren’t lead are they?
     
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