Consealed wiring in plaster

Discussion in 'Electricians' Talk' started by David1974, Sep 14, 2017.

  1. David1974

    David1974 New Member

    Hi

    I am looking at installing a shaver socket and separate illuminated mirror in my bathroom.

    I am aware that this is a special location so needs signing off, but to cut down costs I'm hoping to do some of the work myself - i.e chase the wall out and install the necessary conduit first so the electrician can just come and install and connect up the cabling.

    The wall that both will be on is breeze block with plaster over. I will be chasing the wall vertically from where each will be so it exits in the loft above for connection to the lighting circuit. My question is, how deep do I need to chase and what type of conduit do I need? (plastic oval conduit, metal capping, plastic capping etc)

    The chase (and conduit) will be plastered over and then tiled over once fully installed.

    Cheers

    Dave
     
  2. JP.

    JP. Screwfix Select

    On the assumption that the continuation of circuit is rcd protected then the conduit should be channelled in so that the conduit surface is what 3/8in approx below wall surface (maybe someone will come up with a better measurement because not really aware of that when doing) Use pukka oval conduit (Ega Tube is excellent),, not the ultra cheap stuff which is paper thin and shatters, and prior to fitting conduit in chase wet said in with a what 5 - 1 pva which effectively de dusts the chase for bonding plaster.
     
    Last edited: Sep 14, 2017
  3. unphased

    unphased Screwfix Select

    Hi David. Usually you chop out just the plaster itself, approx. 13mm, to expose the surface of the blockwork, and lay your cable on that, capped with whatever you like, plastic or galv capping, doesn't matter. Some elecricians like to use oval conduit which will sit on the surface of the blockwork and you thread the cable in to it. Lay the cables flat on to the wall, don't twist them, and you will find it much easier to cap. The mirror is usually just a cable sticking out of the plaster at a suitable position which gets wired directly on to it, you can extend off the shaver socket feed if you find that easiest and its close to the mirror.
     
    tore81 likes this.
  4. David1974

    David1974 New Member

    Thanks for your replies, looks like there is an option to do either then. Much appreciated :)
     
  5. Coloumb

    Coloumb Well-Known Member

    Don't bother with capping spend your money on a pint. Clip the cable to the wall then cover in plaster. Believe me in tens mins there will be members on here saying don't do it, it's not regs, it all B.S. mate.
     
    BiancoTheGiraffe and seneca like this.
  6. Joe95

    Joe95 Well-Known Member

    The only error in your thinking is that £1 worth of capping won't buy you a pint! :p
     
    seneca likes this.
  7. Coloumb

    Coloumb Well-Known Member

    :D
     
  8. JP.

    JP. Screwfix Select

    The only problem with that technique Mr C (I know that there is no reg breach) is that it creates static wiring.
     
  9. tore81

    tore81 Well-Known Member

    What is static wiring JP, never heard of that.
     
  10. Risteard

    Risteard Well-Known Member

    There is no point saying you will do some of the work yourself without first securing the permission of the installing Electrician as to what you can or cannot do.
     
    leesparkykent likes this.
  11. Coloumb

    Coloumb Well-Known Member

    Do honestly think he is going to get a spark in?
     
  12. JP.

    JP. Screwfix Select

    Hi Tore let me explain the words ''static wiring''. Static wiring is wiring which has been clipped and plastered over - thus at say socket position for example what you are left with after snipping is exactly the length no more or no less, this cable is immovable, another word for immovable is static. On the other hand if you use oval etc (I always do, no exceptions) then the cable/s is /are movable and if summit goes wrong at socket position etc then you still can pull cable down what another 25 to 50mm or whatever..the cable is movable. Hope this clarify's things Tore.

    I must say that I am not saying Mr C's way is wrong - people do things different ways, and whats good for one is not necessarily good for another,.
     
    Dr Bodgit and tore81 like this.
  13. seneca

    seneca Screwfix Select

    I have to admit JP that I very rarely use capping, just plaster it in. Must give better heat conduction I reckon!
     
    BiancoTheGiraffe and tore81 like this.
  14. Coloumb

    Coloumb Well-Known Member

    Sounds highly commendable mate but it's not something I've ever had an issue with, just leave a large chunk of cable to work with.
     
    tore81 and seneca like this.
  15. JP.

    JP. Screwfix Select

    Dunno what to say Mr C..:)
     
  16. JP.

    JP. Screwfix Select

    Hi Sen. Yes the thermal characteristics are ideal in some situations I would imagine, I can see that whats borderline in cable in conduit calcs would not be if cable is plastered in directly..in other words de rating calcs might show directly plastered in as ok, and cable in conduit might not show so good. Very rare though I would think in domestic installations.
     
  17. Coloumb

    Coloumb Well-Known Member

    If it gives you a hard on mate you knock yerself out fella :)
     
  18. Risteard

    Risteard Well-Known Member

    I'm just taking him at his word in his first post.
     
  19. Coloumb

    Coloumb Well-Known Member

    Yea fair enough. Sozza.
     
  20. tore81

    tore81 Well-Known Member

    Thankyou JP
     

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