Conduit in insulated partition wall

Discussion in 'Electricians' Talk' started by DIY_Adam, Oct 19, 2008.

  1. DIY_Adam

    DIY_Adam New Member

    I understand that any wires I run through a partition wall that is insulated should be run through conduit to prevent overheating.

    Which type should I use, is the flexible plastic stuff ok, or should it be the rigid stuff?

    Thanks
     
  2. seneca2

    seneca2 New Member

    I understand that any wires I run through a partition wall that is insulated should be run through conduit to prevent overheating.

    Are you sure about that Adam? de-rated yes but not sure they need to be in conduit? I'm not saying you're wrong, just haven't needed to check it out yet
     
  3. JP.

    JP. Screwfix Select

    Think the thermal derating calcs (yes I know its largely bull) will still apply M8.

    The so called derating calcs will eliminate overheating scenarios and should be deployed within the expected load situation

    In a nutshell the use of oval etc within the parameters you describe will not eliminate overheating and cannot be used in the design to prevent overheating.

    Tell the sparks what the load is etc and they will advise.

    PS..like your use of conduit..always use it myself and have never had to use derating calcs with the type of loading deployed.
     
  4. Lokkars Daisy

    Lokkars Daisy New Member

    conduit aint gonna help at all as far as derating goes,in fact it will just be a pain in the bum as far as routing cables goes. Just stick to your usual sizes of cables and you won't go far wrong. However if you do intend to run a cable near to it's max capacity for any length of time then you should take into account the derating factors
     
  5. JP.

    JP. Screwfix Select

    How is it a pain using conduit LD? - especially within a partion filled with Rockwool etc? (can appreciate it might not always be a viable deployment though)

    To be honest I think it helps keep the cable within the zones (no stray cabling bending out of zone etc)

    For example..upstairs partition wall light switch.

    From box, oval up into loft (or under the floorboards)..the rest speaks for itself.

    Easy.
     
  6. DIY_Adam

    DIY_Adam New Member

    I think I got that impression from some 'notes on partition wall construction' plus the fact that the wool insulation data sheet says that electrical cables (in a loft situation) should sit on top of the insulation and not under it to prevent overheating.

    If I make sure the wires are in between the plasterboard and insulation (so the insulation doesn't surround the wire from all sides) will this be sufficient without conduit?
     
  7. JP.

    JP. Screwfix Select

    Whatever.
     
  8. sinewave

    sinewave Screwfix Select

    Your installation will use Ref Method 102 if the cable has one of it's sides touching the plasterboard and stud work using Table 4D5


    If you run the cable so it's completely surrounded by the insulation with a min U value of 0.1 W/m2K or just on the inner stud with no plasterboard contact then it's Ref Method 103 with a derating factor of 0.5 off Table 4D5 Regulation 523.7


     
  9. Lokkars Daisy

    Lokkars Daisy New Member

    So that'll be 6mm for the sockets and 2.5mm for the lights nd 16mm for the cooker SORTED :^O
     
  10. cliffy brown

    cliffy brown New Member

    Your installation will use Ref Method 102 if the cable has one of it's sides touching the plasterboard and stud work using Table 4D5


    If you run the cable so it's completely surrounded by the insulation with a min U value of 0.1 W/m2K or just on the inner stud with no plasterboard contact then it's Ref Method 103 with a derating factor of 0.5 off Table 4D5 Regulation 523.7

    *** adam, didnt you know this already
     

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