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Thread: Conduit Riser Bonding Bushing

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    Conduit Riser Bonding Bushing

    Does a GRC conduit riser, soley for the protection of a tray cable from an enclosure to the cable tray, which is fastened to the enclosure with standard locknuts need a bonding bushing attached to the cable tray? The tray cable has an equipment grounding conductor which is attached to the enclosure ground bar and is the effective ground fault current path.

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    Quote Originally Posted by Jsim4109 View Post
    Does a GRC conduit riser, soley for the protection of a tray cable from an enclosure to the cable tray, which is fastened to the enclosure with standard locknuts need a bonding bushing attached to the cable tray? The tray cable has an equipment grounding conductor which is attached to the enclosure ground bar and is the effective ground fault current path.
    Here is part of the awnser but you need to read through 250 as well.

    392.60 Grounding and Bonding.
    (A) Metallic Cable Trays. Metallic cable trays shall be
    permitted to be used as equipment grounding conductors
    where continuous maintenance and supervision ensure that
    qualified persons service the installed cable tray system and
    the cable tray complies with provisions of this section. Metallic
    cable trays that support electrical conductors shall be
    grounded as required for conductor enclosures in accordance
    with 250.96 and Part IV of Article 250. Metal cable
    trays containing only non-power conductors shall be electrically
    continuous through approved connections or the use
    of a bonding jumper not smaller than a 10 AWG.

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    Thank you. I forgot that we have also installed a single 4/0Awg insulated equipment grounding conductor (EGC) that is bonded to the tray every 100'. This same EGC leaves the tray, down the conduit riser and atatches directly to the enclosure grounding buss bar. I feel that since the GRC enters the enclosure through a hole we punched, uses standard locknuts and the ground buss is attached directly to the enclosure, the GRC riser does not need bonding bushings.

    Can you confirm?

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    Quote Originally Posted by Jsim4109 View Post
    Thank you. I forgot that we have also installed a single 4/0Awg insulated equipment grounding conductor (EGC) that is bonded to the tray every 100'. This same EGC leaves the tray, down the conduit riser and atatches directly to the enclosure grounding buss bar. I feel that since the GRC enters the enclosure through a hole we punched, uses standard locknuts and the ground buss is attached directly to the enclosure, the GRC riser does not need bonding bushings.

    Can you confirm?
    That sounds good to me the RMC is going into punched holes so it should be fine IMO.

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