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Best way to get cable through ceiling joists?

Discussion in 'Electrics UK' started by uptown47, 10 Aug 2021.

  1. uptown47

    uptown47

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    Hi all,
    I have to run a cable across a kitchen ceiling. Obviously the joists are all going the wrong way.

    The last time I did something like this I cut holes in the ceiling plasterboard large enough to get my drill in and then bored a small hole through the centre of the joist at the edge of the room to feed the cable through.

    However, I was happy to do that as I knew that the ceiling was getting re-skimmed anyway.

    The new run I'm doing is in the kitchen and I was hoping to avoid a full re-skim of the ceiling.

    I've seen some YouTube video showing "flexible drill bits" and wondered if anyone has used them?

    Or if people use a right-angle drill or a smaller drill so that I can maybe reach up through the small downlighter holes?

    Or maybe cutting the plasterboard under the joist and channeling a bit out for the cables and overlaying it with some galvanised steel for protection?

    Or is there another way of doing it that I'm not aware of?

    Tips / tricks / techniques will be most welcome. Thanks :)
     
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  3. BS3036

    BS3036

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    Never notch the underside of joists.
     
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  4. uptown47

    uptown47

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    Yep, I wasn't sure about that. I'm a DIY'er and I remember looking into this a few years ago when I ran the speakers in the living room. If I remember rightly (and, at my age, that's not guaranteed!!) I think I read that you should try and drill in the centre of the joist but not more than 30% of the length away from a load bearing wall? There was something about the hole size as well (which would make sense) but can't remember what that was as I only needed relatively small holes for the speaker wires. Thanks.
     
  5. oldbutnotdead

    oldbutnotdead

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    What's above the ceiling? If it's a room then empty it and lift a floorboard, then drill or notch as preferred (within the limits).
     
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  6. uptown47

    uptown47

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    Good idea but the floor above has laminate down that goes right under the skirting so I can't really get all that up to get the floorboards up without a load of mess and work unfortunately. :(

    (I should also say that the centre of the room is under the bathroom which has a tiled floor as well)
     
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  7. sparkwright

    sparkwright

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    If you don't fancy removing large sections of plasterboard and re-skimming
    then
    the usual way will be notching the plasterboard below the joists and fishing the cables.

    Other options include fitting coving so the wiring is behind that.
     
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  8. Tigercubrider

    Tigercubrider

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    Coving/ boxed in air ducts /along tops of cupboard runs?
     
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  9. uptown47

    uptown47

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    I thought notching under the joists was a bit of a no-no? Coving is a really good idea. Thanks. :)


    Thanks, running along the tops of cupboards is a good shout - especially for speaker cable. I'm presuming that this method wouldn't be allowed for any cable carrying 'mains' though, would it?
     
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  11. sparkwright

    sparkwright

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    You can notch the plasterboard, but don't notch the actual joist.
     
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  12. uptown47

    uptown47

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    But that wouldn't be deep enough for the cable would it? If the plasterboard is only 12mm and then you have to clip the cable to stop any movement then try and plaster on top of the cable and clip? That would only leave a really thin amount of plaster on between the cable and the surface would it not?

    I've never done it so will certainly bow to your experience but just asking the question?

    Thanks :)
     
  13. sxturbo

    sxturbo

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    its fine, put it in conduit and it's extremely unlikely it will ever get damaged.

    you can have live wires in conduit up and down and across walls no problem, no different on the top of the cupborad where no one can see, an even fewer people venture.
     
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  14. conny

    conny

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    Rather than circular/oval conduit why not use some square/rectangular mini trunking along the tops of the cupboards.
    Personally I would find it easier to fix into place and, if anyone should venture up there, be more aesthetically pleasing.
     
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  15. sxturbo

    sxturbo

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    i was thinking of the flat square stuff you can clip the cover on
     
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  16. Lower

    Lower

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    If you are careful, you can cut a large enough section of plasterboard out between each joist to allow you get your drill in without damaging the skim too much around the hole. Then fit support batons across each hole and screw the plasterboard back into place. Then fill the cuts with easyfill and sand flush.

    I've used this method successfully to do exactly what you want to do and avoided having to have the whole ceiling skimmed. If you're careful when you cut the plasterboard (use a jigsaw or a multi tool) the amount of filling required is minimal and you can't see where the holes where.
     
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  17. JohnD

    JohnD

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    If this is a kitchen, with wall cabinets, then mini trunking screwed to the wall (not the cabinets) is fine, and will not be seen above the cabinets.

    You can paint it to match the wall if you want

    This is easier after cutting and before fixing.
     
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