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Thread: RMC Bushing requirement

  1. #1
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    RMC Bushing requirement

    An electrical contractor has stubbed up rigid metal conduits from a control cabinet as shown in the attached picture. They did not install a bushing where the cables leave the conduit and contend that the installation meets NEC requirements. I think it's sloppy because the cables are subject to chafing with any vibration that the system could see and a simple plastic after-the-fact split bushing is required. The only NEC section I can see as applicable is 344.46, Bushing, which states that - where a conduit enters box, fitting or enclosure a bushing shall be provided to protect the wires.... but the pipes enter free air.
    Is this a legitimate concern, and if so, is there another NEC section that would apply?
    Thanks for any assistance.
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    Are those sleeves for running cables, it's hard to tell from the photo. Look at 300.15(C).
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

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    I predict a loud "BOOM" in the future that no amount of expanda foam is going to muffle...


    JAP>

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    Code or not extremely sloppy

    Sent from my SM-G965U using Tapatalk

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    Quote Originally Posted by infinity View Post
    Are those sleeves for running cables, it's hard to tell from the photo. Look at 300.15(C).
    The one on the right looks like individual THHN conductors to me
    Sometimes I don't know whether I'm the boxer or the bag.

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    thanks

    Quote Originally Posted by infinity View Post
    Are those sleeves for running cables, it's hard to tell from the photo. Look at 300.15(C).
    I think 300.15(C) applies.

    I think they're sleeves to cable tray, made up of at least some type TC cable.

    I've added the other two pics my friend sent me from the field.

    And yes it is very sloppy, and we're all paying the bill
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    Blame it on the left handed electrician,,,,,,It seems all the bolts in the strut straps were installed left to right.


    JAP>

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    Quote Originally Posted by mayanees View Post
    An electrical contractor has stubbed up rigid metal conduits from a control cabinet as shown in the attached picture. They did not install a bushing where the cables leave the conduit and contend that the installation meets NEC requirements. I think it's sloppy because the cables are subject to chafing with any vibration that the system could see and a simple plastic after-the-fact split bushing is required. The only NEC section I can see as applicable is 344.46, Bushing, which states that - where a conduit enters box, fitting or enclosure a bushing shall be provided to protect the wires.... but the pipes enter free air.
    Is this a legitimate concern, and if so, is there another NEC section that would apply?
    Thanks for any assistance.
    Bridgeport makes split/threadless bonding bushings, that can be installed on unthreaded RMC without re-pulling wires. This way you can remediate this situation and protect the wires from abrasion, without major surgery to rework those wires.
    https://www.bptfittings.com/store/sp...ze-2-inch.html

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    I wouldn't think you'd be allowed to use minimally expanding foam in contact with the insulation of the cable. I don't think it's listed for use and potentially it could degrade the insulation of the cable because of solvents in the foam. I also thought that conduit larger than 3/4 required bushings no matter what but I could be wrong about that.
    The world is round, you will get there no matter what path you take.

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    Quote Originally Posted by rlundsrud View Post
    I also thought that conduit larger than 3/4 required bushings no matter what but I could be wrong about that.
    It's #4 AWG and larger, where bushings (plastic or otherwise) are required no matter what. Smaller than that, and conduit connectors can be used without a bushing (albeit not what I would specify), but threaded conduit ends require one.

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