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Wall Cavity Wiring.

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Good morning on this bright and sunny start,


                          Q. Which regulation(s) specifically prohibit(s) the installation of cables in brick and block cavity walls within the cavity?


in a, Older premises?


    b, Newer premises?


If regulations exist, what reasons are provided for the prohibition? Or are we just concerned about chemical damage of cable insulation if the cables are in contact with some types thermal insulation?


Z.
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  • 0
    I suspect no prohibition in the wiring regs apart from the fact that cavity insulation arrangements may make calculating a current rating a bit tricky.  Building regs like things crossing the cavity to be arranged to not cause un-necessary bridging. A quick nip across for an outside light is fine,  assuming not drilled up hill and filling with water, and I suspect a short drop between two  indoor sockets is OK too assuming it is well done,and not stuffing the cavity with loads of tangled slack . 

    I have seen plastic flex-conduit on wiring in a cavity with a foam infill, so I assume that was done to avoid questions of chemical compatibility.

    It does not feel like good practice, but I do not think it is an immediate fail in all cases

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  • 0
    I suspect no prohibition in the wiring regs apart from the fact that cavity insulation arrangements may make calculating a current rating a bit tricky.  Building regs like things crossing the cavity to be arranged to not cause un-necessary bridging. A quick nip across for an outside light is fine,  assuming not drilled up hill and filling with water, and I suspect a short drop between two  indoor sockets is OK too assuming it is well done,and not stuffing the cavity with loads of tangled slack . 

    I have seen plastic flex-conduit on wiring in a cavity with a foam infill, so I assume that was done to avoid questions of chemical compatibility.

    It does not feel like good practice, but I do not think it is an immediate fail in all cases

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