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Discussion Forum

running wire in conduit

markledbury | Posted in General Discussion on November 20, 2007 05:44am

Greetings everyone,

I’m planning to add an exterior outlet on my house.  I’m going to add a new 20 amp breaker in the main electrical service panel which is on the south side of the garage, run the 12 ga. wire up that wall, over the top of the bottom chord of the roof trusses, down the north wall of the garage, into the crawlspace, and finally install the outlet on the north side of house. I’d like to put the wire in a conduit as it runs down the north wall of the garage.  the length of this conduit would be about 10 feet. Can I run NM cable in the conduit?  If so, do I need to put junction boxes at both ends of the conduit, or are there other options for the conduit ends?  When I penetrate the north wall of the garage, do I need a special connector to get through the wall?

Thanks,

Mark

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Replies

  1. User avater
    IMERC | Nov 20, 2007 06:45pm | #1

    go for it...

    there's clamps made just for that purpose...

    romex to tube...

    will you have a surface mounted box on the north wall???

     

    Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

    WOW!!! What a Ride!
    Forget the primal scream, just ROAR!!!

    1. markledbury | Nov 20, 2007 07:00pm | #2

      Do  you  mean the north wall of the garage or the north wall of the house, where the exterior outlet will be placed?

      Mark

       

      1. User avater
        IMERC | Nov 20, 2007 08:15pm | #4

        electrical service panel which is on the south side of the garage, run the 12 ga. wire up that wall,

        Surface mounted????

        over the top of the bottom chord of the roof trusses,

        will you be going eeast / west with this wire on top of the truss chords to get to the north wall??? 

        down the north wall of the garage,

        internally or externally???

        into the crawlspace,

        and finally install the outlet on the north side of house. 

        surface mounted or recessed???

        Can I run NM cable in the conduit? 

        yup...

        If so, do I need to put junction boxes at both ends of the conduit, or are there other options for the conduit ends? 

        use romex to EMT clamps...

        When I penetrate the north wall of the garage, do I need a special connector to get through the wall?

        no...

        but make sure the wire is mechanically protected... 

        Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->

        WOW!!! What a Ride!Forget the primal scream, just ROAR!!!

        1. markledbury | Nov 21, 2007 12:53am | #5

          electrical service panel which is on the south side of the garage, run the 12 ga. wire up that wall,

          Surface mounted????

          Its mounted between the studs

          over the top of the bottom chord of the roof trusses,

          will you be going eeast / west with this wire on top of the truss chords to get to the north wall??? 

          I'll have to go East for  few feet (which is parallel to the trusses)

          down the north wall of the garage,

          internally or externally???

          the wire would run down the outside of the drywall (still inside the garage)

          into the crawlspace,

          and finally install the outlet on the north side of house. 

          surface mounted or recessed???

          recessed into the wall

          Can I run NM cable in the conduit? 

          yup...

          If so, do I need to put junction boxes at both ends of the conduit, or are there other options for the conduit ends? 

          use romex to EMT clamps...

          When I penetrate the north wall of the garage, do I need a special connector to get through the wall?

          no...

          but make sure the wire is mechanically protected...

          Thank you :-)

          1. User avater
            IMERC | Nov 21, 2007 02:33am | #10

            the wire would run down the outside of the drywall (still inside the garage)

            into the crawlspace,

            Can I run NM cable in the conduit? 

            yup...

            If so, do I need to put junction boxes at both ends of the conduit, or are there other options for the conduit ends? 

            use a romex to EMT clamp on the begining of the run...

            at the turn into the crawl space use a LLB or SLB with a stub of conduit protruding into the crawl space...

            use EMT conduit and not plastic... 3/4" will make yur life easier over 1/2"....

             

            When I penetrate the north wall of the garage, do I need a special connector to get through the wall?

            no...

            but make sure the wire is mechanically protected... 

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->

            WOW!!! What a Ride!Forget the primal scream, just ROAR!!!

          2. markledbury | Nov 21, 2007 02:45am | #11

            Thank you IMERC, Mike Hennessy, and everyone else that responded to my question.  I now have the info I need to do the project.

            Have a great Turkey Day!!

            Mark

          3. DanH | Nov 21, 2007 03:01am | #12

            One other thing: When pulling the romex through the conduit, unroll and unkink it first. Don't let the cable simply spiral out of the box and into the conduit or the twists will create a major problem for pulling. (Don't ask how I know.)
            If your view never changes you're following the wrong leader

  2. MikeHennessy | Nov 20, 2007 07:12pm | #3

    I'm no electrician or code wizard, so let's see if I get this right. ;-)

    You can run Romex in thinwall for a short length to protect it mechanically. Don't know the code reference tho'. You need to protect the wire where it enters/exits the conduit. I have used just a regular box connector if that end of the conduit is out of the way, like up at the ceiling. I use a box if it's more exposed. In your case, you might want to use a small connector, like a 90° entrance box or an elbow with a cover, to carry the conduit a ways into the crawl space where it's out of harm's way -- it'll be easier to fish that way too.

    If you are running the wire so it will be exposed outside, even a little bit, you need to use outdoor wiring, usually UF cable, depending on your local codes. You don't say what your wall is made of, but I have either run the cable throug the wall in pvc conduit (so no special cable is needed, since it's not exposed), used UF cable and just fished it through a hole (sealed with caulk) and into a box, or mounted the box in or on the wall and fed the wire from the back, so it's not exposed.

    Don't forget that you need a GFCI and an "In Use" cover on your exterior outlet.

    Mike Hennessy
    Pittsburgh, PA

  3. caseyr | Nov 21, 2007 01:31am | #6

    I don't have the citations, but I was told that in earlier versions of the NEC, the code either did not allow Romex in conduit for more than short distances, or people interpreted the code to that effect. I was also told that later versions of the code did allow for Romex in conduit for normal wiring distances. However, you have to use the proper size conduit so that you do not overfill. I don't know what the area of Romex is for various sizes, but tables showing the allowable fill percentages for various sizes of conduit are readily available.

  4. User avater
    CapnMac | Nov 21, 2007 01:56am | #7

    Ok, are you running this last bit of conduit on the inside wall of the garage or the outside (got lost while Marty was asking all the directions).

    If it is inside, you could go with metallic cable, which would already have cinductors within it--then it's just marrying the romex to the MC at a properly fitted junction box.

    Now, 'regular' conduit will likely look neater.  Use a "pullox elbow" where you turn out to the exterior box and you'll save your self some effort.  That's since you can set the outside box on it's own "tail" which you can then run inside and trim to need.  (Sometimes trimming from the outside leaves something to be desired, like knuckle flesh on brick veneers <owowowow>).

    Why not run outside?

    Well, you can.  The trick of it is that where the conduit comes into the exterior box is not the same elevation as where it "wants" to sit, in clips, on the wall.  It just takes a couple of gentle bends with the conduit bender--but, the experience it takes to make those two, simple, subtle bends is hard to come by.  And, trust me, not bending makes for a pretty install.

    Occupational hazard of my occupation not being around (sorry Bubba)
    1. markledbury | Nov 21, 2007 02:33am | #9

      I'm running the cable down the outside of the wall (its still inside the the garage) from the garage ceiling to a point where I can penetrate the wall and run the rest of the cable in the crawlspace to its final destination.  I don't want to open up the wall to put the cable inside, between the studs. 

      Thanks,

      Mark

  5. DanH | Nov 21, 2007 01:59am | #8

    Yes, you can run NM in the conduit, just make sure you use stuff that's large enough.

    You need a "bushing" where NM enters the conduit. This can be just a box fitting without the box -- the rounded edge of the hole is what's required.

    If your view never changes you're following the wrong leader

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