PVC Conduit to NMD90 Transition

Discussion in 'Electrical Forum discussion & Blog' started by dlarrivee, Feb 18, 2011.

  1. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    I'd like to run power out to a shed for some lights and an outlet.

    I plan to go underground in pvc conduit with THWN conductors in it.

    Generally you'd probably use a PVC LB on the exterior of the home to change directions with, and a junction box on the inside of the home... Unfortunately I'd rather not have an access panel in a finished bathroom to keep the junction box legal.

    So instead I'd like to use a larger PVC weather tight junction box on the exterior of the home, rather than a smaller LB, that way I can splice my THWN to my NMD90 in that box rather than inside the home.

    I'm just not sure what the proper way of running 12/2 NMD90 through the exterior wall into the PVC box is... I assume I should use a PVC nipple, but what about the interior end of the nipple, do I just need a bushing of some sort?
  2. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,532
    Location:
    North Carolina
    You are over the border and I think under a little different rule than us southerners.
    Down here we don’t like the idea of having NM cable outside even for a short distance. I would recommend that you use a UF cable to the junction box and don’t see anything wrong with the installation other than the cable going through the wall to be made up outside.
  3. drick

    drick In the Trades

    Messages:
    392
    Female connector or a male (with a bushing if larger than 1/2") should be fine.

    -rick
  4. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    The cable itself wouldn't ever be outside, it would come into the backside of the weather-tight junction box on the exterior.
  5. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,532
    Location:
    North Carolina


    Help me out here, please. Is the word "exterior" you use above meaning outside?
  6. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    I found this on Google Image Search:
    [​IMG]

    Whoever installed this junction box, simply drilled a hole in the back of the box... I'd rather have a pvc connector that would at least reach through the sheathing... Or am I creating more work for myself?
    Last edited: Feb 20, 2011
  7. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    Except for the lack of a connector into the back of that box this is a commonly accepted trade practice.
  8. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    That connector is what I wanted to clarify... I suppose almost any type of connector would "work", but I'd like to know what the best practice is whenever I do something. Is there no requirement for the connector to clamp the cable where it enters the box?
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