Announcement

Announcement Module
Collapse
No announcement yet.

Conduit to metal box bushings

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Conduit to metal box bushings

    I am in the process of installing some outlets in my basement workshop along the concrete wall. I used 4x4x2-1/8" metal boxes and 1/2" EMT with the screw clamp conduit to box fittings. I plan to run 12-2 romex and remove the outer jacket where it runs inside the conduit. I bought some grey bushings that thread onto the exposed threads of the conduit to box adapter but there is not enough threads exposed on the connectors after the tab nut is used to secure the fitting to the box. Only one of the five locations had enough exposed threads.

    Do I need to use a bushing there or will the conductor insulation be OK against the fitting?

  • #2
    Re: Conduit to metal box bushings

    Post removed until I can post some good pictures. Words just don't work for me today.
    Last edited by Woussko; 02-19-2008, 04:47 PM.

    Comment


    • #3
      Re: Conduit to metal box bushings

      You don't need a bushing in that application until use #4 or larger conductors. You do however need a fitting of some sort to protect the NM cable from abrasion on the other end of the conduit. You can use an EMT connector, coupling, or best would be an EMT to NM connector.

      Article 300.4(F) of the NEC covers this.

      Jeff

      Comment


      • #4
        Re: Conduit to metal box bushings

        I bought some additional conduit to box fittings. The conduit to NM-B fittings were almost three times the price. I still wonder about the 1/2" plastic bushings - even if they needed to be used in my application, I couldn't because there aren't enough exposed threads on the fitting.

        Thanks for the help.

        Comment


        • #5
          Re: Conduit to metal box bushings

          Originally posted by khe View Post
          I bought some additional conduit to box fittings. The conduit to NM-B fittings were almost three times the price. I still wonder about the 1/2" plastic bushings - even if they needed to be used in my application, I couldn't because there aren't enough exposed threads on the fitting.

          Thanks for the help.
          The reason the threads are so short is because the NEC only requires bushings when using a #4 or larger ungrounded conductor in a raceway entering a box or cabinet or similar enclosure. The NEC also limits 1/2" EMT to a single #4 conductor. 300.4(f) of the NEC states "ungrounded" conductors, seeing as how you cannot run just one single ungrounded conductor without a nuetral or another ungrounded conductor you can't by code put yourself ina situation where you need a bushing. To do that would mean more than one #4 or larger conductor, and that is against code in a 1/2" EMT.

          Jeff

          Comment


          • #6
            Re: Conduit to metal box bushings

            Originally posted by piette View Post
            The reason the threads are so short is because the NEC only requires bushings when using a #4 or larger ungrounded conductor in a raceway entering a box or cabinet or similar enclosure. The NEC also limits 1/2" EMT to a single #4 conductor. 300.4(f) of the NEC states "ungrounded" conductors, seeing as how you cannot run just one single ungrounded conductor without a nuetral or another ungrounded conductor you can't by code put yourself ina situation where you need a bushing. To do that would mean more than one #4 or larger conductor, and that is against code in a 1/2" EMT.

            Jeff
            That makes me wonder why a 1/2" plastic bushing is even produced?

            Comment


            • #7
              Re: Conduit to metal box bushings

              Originally posted by khe View Post
              That makes me wonder why a 1/2" plastic bushing is even produced?
              When you use ridgid pipe, you must use the bushing no matter what size wire you run.

              Comment

              Working...
              X