Junctions in conduit

Discussion in 'Electricians' Talk' started by markvr, Mar 10, 2013.

  1. markvr

    markvr New Member

    I have some wiring in my garage (done by a sparky believe it or not...) where the wire is quite loose, just tacked to the wall with clips, and there are a few junction boxes as well as the usual switches etc.

    I'd like to enclose the wiring in plastic conduit to make it neater and more protected, but I can't for the life of me see how the junctions would work!  All the conduit junction boxes are just empty boxes, e.g. http://www.screwfix.com/p/tower-3-way-tee-box-20mm-black-pack-of-1/82706

    Am I supposed to put a "normal" junction box inside of that?  Or do conduit junction boxes exist somewhere that already have wiring blocks in?

    Seems a stupid question but I can't found out anywhere!

    Thanks!
     
  2. Sean_ork

    Sean_ork Screwfix Select

    they are for conduit junctions, not wiring junctions - they are open to ease the installation of wiring

    an adaptable box is a more suitable enclose for wiring junctions
     
  3. markvr

    markvr New Member

  4. Sean_ork

    Sean_ork Screwfix Select

  5. markvr

    markvr New Member

  6. Lectrician

    Lectrician Screwfix Select

    Rewire it.

    Conduit should be wired with singles, and if done correctly, no joints.  Circular boxes are used for drawing in cables, not jointing.

    The BESA fixings of a circular box will fit pendants, batten holders, and two for behind fluorescent fittings.
     
  7. J.P.

    J.P. New Member

    BESA boxes are also good for some wall lights.. :)
     
  8. markvr

    markvr New Member

    Sorry, I must have missed something obvious because I just don't get it.  I have an existing circuit that requires regular junction boxes, e.g. the one linked above.  How can I rewire this without junction boxes in order to enclose the wiring with conduit?  If it was possible to do it without junction boxes, why use them in the first place?

    I must have missed something but I don't see what...

    e.g. for lighting, cabling enters a junction box, then there's a run that goes to the switch, and two runs that go to two lights.  How could this be enclosed in conduit, and not use a junction box?
     
  9. J.P.

    J.P. New Member

  10. markvr

    markvr New Member

    "and other stuff - just work it out really" - that's the bit I'm stuck on!!

    I can figure out how to install the conduit, that's easy.  It the wiring junctions that apparently I don't need, but can't see how to replace.

    e.g, as I put above: for lighting, cabling enters a junction box, then there's a run that goes to the switch, and two runs that go to two lights.  How could this be enclosed in conduit, and *not* use a junction box?  To try and be even clearer, I'm referring here to a wiring junction box, e.g. http://www.screwfix.com/p/crabtree-4-terminal-20a-junction-box/70677?_requestid=176351

    If you don't put wiring junctions in the conduit, where *do* you put them!!
     
  11. J.P.

    J.P. New Member

    I don't really know Mark - I mean its the lighting circuit so really the lighting terminations should be in the rose which equates to a BESA circular box being used for said - or all terms would be in the switch box (aka loop in box) - the way yours has been wired will need the JB which would be an adaptable box or something like it with term strip inside - which you can purchase unless you are prepared to revamp to either loop in rose or loop in box..sounds like the sparky was a bit bodgy tbqh.. not the way myself as a DIY'er would go about things really..:)

    Anyway it does sound as though you are going to end up using the 20mm T JB so stick a term block in there and wire it - not very good though and that 1.5 stranded might necessitate a 10 Amp term block, and it might not fit, and wires might scrunge and stuff - you know you screw the lid on and it bends as the wiring scrunges and stuff
     
  12. J.P.

    J.P. New Member

    Please don't say there's JB's on the power
     
  13. unphased

    unphased Screwfix Select

    Hi mark

    Conduit is not the correct way of doing this. You should find it much easier (and a lot simpler) to use mini-trunking. Mini-trunking is ideal for enclosing T&E wiring and you can install it around the existing wires. The lids clip in to place over the wires. There are three sizes of trunking that you may find useful, MT2 (16x25), MT3 (16x38) and MT4 (25x38). You can also get these with adhesive backing, but it is unlikely to be of any advantage on a garage wall. Where junction boxes exist simply change these for surface patress and blanking plate and use connector blocks inside, or use proprietary adaptable boxes.

    Conduit is designed to be fixed as a complete system then wires are pulled in afterwards.

    Trunking is the solution.

    Regards
     
  14. Lectrician

    Lectrician Screwfix Select

    [​IMG]

    Look here: http://www.screwfix.com/c/electrical-lighting/conduit-wiring/cat830458
     
  15. unphased

    unphased Screwfix Select

    Singles should not be used outside of conduit. And you need a stuffing gland on top of the metal switch, a cover on the fuseboard and a ceiling rose for the bulb...
     
  16. Lectrician

    Lectrician Screwfix Select

    A stuffing gland?  Really?

    A female conduit adaptor would be my choice.  Males take up too much room.

    [​IMG]
     
  17. seneca

    seneca Screwfix Select

    I can't see what all the fuss is about, 20mm plastic conduit will fit straight into the type of box in your picture and there are lots of other fittings that will connect on to the conduit, eg, bends etc. you just need to put your own connector blocks (choc-blocks) inside the boxes.
    As others have said you can also use adaptable boxes  with male or female adaptors to attach the conduit to the boxes, it's better to do it this way where you have a number of connections to make as there's not a lot of space in the beezer boxes.
     
  18. Lectrician

    Lectrician Screwfix Select

    Not BEEZER - BESA!  British Engineering Standards Association.  A shame not all lighting manufacturers adhere to this!

    Not a fan of terminal blocks in conduit boxes myself - they are for inspection and to aid pulling in cables, not for jointing.  If you want to joint (and there should be no need if wired well), then adaptable 'gewiss' type boxes can be used - 100x100x50 being the most common.

    I much prefer conduit in a garage to mini-trunking.
     
  19. markvr

    markvr New Member

    Thanks all, it's given me some info to think about!  I prefer the idea of conduit, it looks stronger than trunking but I'll see how I figure it out with the wiring.  I hadn't realised you're supposed to wire it with single core cable.  I'm still not sure how it's going to work but I'll try and figure it out.

    Putting terminal blocks into a conduit junction box, or using an adaptable box with blocks would be the easiest thing to do.  Then I don't need to replace all the existing wiring, and work out how to do new wiring.

    thanks!
     
  20. unphased

    unphased Screwfix Select

    He is DIY and it would be a PITA to get all the wire threaded through the stuff. Trunking is the way forward. If using conduit he would have to strip it all off and virtually start over. Trunking can be 'folded' behind the wires that are there.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice