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Good Practice

RustyH

Just wondered

Does anyone else do these two things. 

1) add a radius to cables going trough and then along joists to put less stress on the cable with tight bends?

2) due to the nature of low cost manufacturing, I find the edges of the fire rated clips to be sharp enough to cut in to the insulation if any manoeuvring of cables is carry out. So I add a plastic clip at any bend or end of run, so give a "softer" fixture at any possible movement point.

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  • 0

    For lofts I'd never drill ceiling joists - they're way less substantial than floor joists and in the case of where they're part of a trussed rafter system definitely not meant to be cut into in any way by design. Loft thermal insulation complicates things - generally (especially for non-lighting circuits) you'd want to avoid running the cables within the insulation - traditionally they were laid above, but as the requirements move towards thicker layers, I'm tending to prefer to keep all the cables below the insulation - on top of the plasterboard between joists to allow heat from the cables to escape downwards and hopping over joists where the cables need to run at right-angles. Clipping varies depending on the situation - if the ceiling are yet to go up then some clips to keep things in the right place during construction certainly, on a retrofit, fewer are likely to be needed. Certainly clipped neatly where cables are run along woodwork above the insulation (along perlins and the like), but otherwise I'm happy to leave cables resting on plasterboard between joists.

        - Andy.

  • 0 in reply to AJJewsbury

    Hi Andy,

    Sorry, wasn't referring to drilling or notching loft joists, instead clipping to the sides but below the 50mm requirement. As I had read that the sides of joist can be vulnerable, so the 50mm requirement should be applied there also?

    Good point on sinking the heat down through the plasterboard when laying on top.

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  • 0 in reply to AJJewsbury

    Hi Andy,

    Sorry, wasn't referring to drilling or notching loft joists, instead clipping to the sides but below the 50mm requirement. As I had read that the sides of joist can be vulnerable, so the 50mm requirement should be applied there also?

    Good point on sinking the heat down through the plasterboard when laying on top.

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