conduit to burry into solid walls

Discussion in 'Electricians' Talk' started by rk_diy, Dec 4, 2019.

  1. rk_diy

    rk_diy Member

    When rewiring, I do not want put the cables into wall directly with capping but would prefer to chase and insert conduits with deep metal boxes into solid walls, then plaster over. (So that I can pull cables later when needed)
    -what conduits should I use? (larger 20-25 mm) It seems PVCs are cheaper but not good with sticking to the filling.
    - whats the best way to prevent any cracks when covering over the conduits?
  2. Comlec

    Comlec Screwfix Select

    If you are rewiring then all the cables you need for your design will be installed. Why would you want to pull cables at a later date?
    I use oval conduit (25mm) more than enough room for 2 x 2.5 T&E or 3 x 1.0 T&E for lighting drops. I try to chase so that conduit is a minimum of 5mm below the finished plaster.
    Get a good plasterer:)
  3. Tony Goddard

    Tony Goddard Well-Known Member

    If you are wanting to go the conduit route use steel conduit (which plaster sticks well to), you can get fittings made by a company called CONLOK (ebay have them) which are attached with a grub screw rather than the need to thread the conduit.
    There is a special hook headed nail made for fixing conduits in the chases prior to plastering.

    Attached Files:

    rk_diy likes this.
  4. rk_diy

    rk_diy Member

    its an old house with solid walls. Its not electric but possibly data/network wires for home-automation. If I can, better to put a separate empty metal conduit to minimise the interference.
  5. Tony Goddard

    Tony Goddard Well-Known Member

    Fair enough, as a commercial/industrial spark I love metal conduit!! make sure you use bushed fittings on the ends like the ones in my pic, otherwise the cable will be shredded on the burr edge (deburr the end of the conduit with a file too)
  6. rk_diy

    rk_diy Member

    Actually, I think better if I find a commercial electrician :), as I would like to terminate all the wires from sockets, switches and lights in a "distribution board" and do the radial connection there rather then usual one ring for sockets and switch-box connections for lights. (for same reason: centralized control for automation)
  7. dobbie

    dobbie Screwfix Select

    The hook headed nail is called a Crampet.
    You also should put tube ends (rubber bushes) on the end of the conduit not at the box.
  8. DIYDave.

    DIYDave. Screwfix Select

    I’ve chopped in large maxi plastic trunking a few times when mounting a tv on the wall. Can’t stand seeing a wall mounted tv then cables running down face of wall

    Worse when you have a unit underneath tv with games consoles, sky box, sound bars, etc, so even more ugly cables running up to tv

    I’ve chopped in 100x50 maxi trunk and recently 50x50mm, set around 10mm below plaster surface, plug and screw to wall

    Note that maximum depth of chase in brick/block wall allowed is one third of wall depth (not including plaster/render)

    Use deep metal back boxes and I cut out bottom section of top box, top section of bottom box with angle grinder, chop in boxes top and bottom of trunking, plug and screw

    Score plastic lid of trunking with Stanley knife, PVA lid then chuck some sand at it, leave to dry (could use ‘blue grit’ but I don’t want to buy any :)

    PVA wall chase, scrim tape and bonding plaster, leave around 3mm below finish surface, allow to dry

    Finish with EasiFill, plaster, prep, paint - not had any cracks

    I drop a draw wire down trunking, use Earth singles, at least dbl length of trunking and curl both ends up in back boxes, use for pulling through cables

    Finish top and bottom boxes with brush plates, either single/dbl gang to suit

    Maybe some of this will be relevant to your question ? :confused:
  9. Draetsir

    Draetsir Member

    ConLok is absolute poo. If you want to use steel conduit use real steel conduit. For drops into accessories PVC would be much more sensible though.
    dobbie likes this.
  10. Draetsir

    Draetsir Member

    You could just use female bushes to protect it instead of those rubber things. Really this is a job for PVC though. It's only drops and not a real conduit system for singles.
  11. dobbie

    dobbie Screwfix Select

    I agree, but it cuts out the job of screwing the tube though, when using the rubber ones.
    candoabitofmoststuff likes this.
  12. collectors

    collectors Member

    Best to use the black tuff conduit & if worried about plaster cracking, put some plasterboard jointing tape around the tube before you fix it in the wall.

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