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Thread: Bonding Required For Liquidtight Flexible Metal Conduit

  1. #1
    Join Date
    Dec 2016
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    New York
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    4

    Bonding Required For Liquidtight Flexible Metal Conduit

    Hi,
    We are installing immersion heaters and we have (3)1-1/4" RGS conduits running from control panel to immersion heaters. We use Liquidtight Flexible Metal Conduit before termination to the heaters. Each conduit has ground in it. However, the residence engineer is asking for bonding between the RGS and the immersion heater. According to Article 250.118(6), EGC has been installed inside the conduit. Do we still need bonding along the Liquidtight Flexible Metal Conduit?

    Thanks.

  2. #2
    Join Date
    Jul 2003
    Location
    New Jersey
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    23,770
    IMO no. The RMC is bonded on one end and depending on the circuit size within the LFMC it already may be bonded on both ends. Look at 250.118 for LFMC as an EGC.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  3. #3
    Join Date
    Feb 2003
    Location
    Somewhere over the rainbow
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    3,244
    The LTFMC is bonded at both ends. You are not using the flexible conduit as an EGC so IMO the 250.118 does not apply, but I agree with infinity the external bonding is not required.

    The designing engineer could be the AHJ, so you may have to install per his/her design requirements.
    Edward
    The only thing I know, is the progressive discovery of my ignorance


  4. #4
    Join Date
    Feb 2003
    Location
    Illinois
    Posts
    23,281
    Quote Originally Posted by AungYe View Post
    Hi,
    We are installing immersion heaters and we have (3)1-1/4" RGS conduits running from control panel to immersion heaters. We use Liquidtight Flexible Metal Conduit before termination to the heaters. Each conduit has ground in it. However, the residence engineer is asking for bonding between the RGS and the immersion heater. According to Article 250.118(6), EGC has been installed inside the conduit. Do we still need bonding along the Liquidtight Flexible Metal Conduit?

    Thanks.
    That is the common practice for industrial work around here and has been since I started in 73. They always specify the internal wire type EGC and an external bonding jumper around the LFMC. It is not required by the NEC, just required by the project specifications.
    Don, Illinois
    Ego is the anesthesia that deadens the pain of stupidity. Dr. Rick Rigsby
    (All code citations are 2017 unless otherwise noted)

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