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Thread: Bonding conduit at each end

  1. #1
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    Bonding conduit at each end

    When bonding of ferrous conduit is required at "each end of the raceway" as in NEC 2014 250.64(E)(1), how do you interpret "each end" when there are several sticks of conduit? One application is a GEC from a photovoltaic inverter to the GE at the service panel as required by 690.47(D), where the GEC runs about 60 feet and there are more than 6 sticks of EMT conduit. Does "each end" mean a bonding bushing at each end of the GEC, one at the inverter and another at the service panel, or a bonding bushing at each end of each EMT stick?

  2. #2
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    6 lengths of EMT coupled together with 5 couplings would require bonding at each end of the complete raceway run.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  3. #3
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    So only 2 bonding bushings.
    Is the 250.97 requirement similar? For circuits of over 250V the electrical continuity of metal raceways shall be ensured using methods of 250.92(B) - OK to have a bonding bushing or other listed method just one on each end?

  4. #4
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    Quote Originally Posted by SolarAlternativesDesign View Post
    So only 2 bonding bushings.
    Is the 250.97 requirement similar? For circuits of over 250V the electrical continuity of metal raceways shall be ensured using methods of 250.92(B) - OK to have a bonding bushing or other listed method just one on each end?
    That would depend on how the raceway was terminated in each end. Some methods using standard locknuts and connectors comply, other methods do not.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  5. #5
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    If we terminate the raceway with a bonding bushing at the array-side junction box, and the inverter enclosure is nonmetallic, for example, would the sections of conduit need to be bonded with something like threadless fittings or bonding-type locknuts or bushings in 250.97?

  6. #6
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    I should have said with a bonding bushing at the inverter enclosure, not a nonmetallic enclosure.
    Anyway, my point is that after I have determined and accomplished the needed bonding at the ends of the circuit I still don't understand how the electrical continuity needs to be accomplished between sections of raceway.

  7. #7
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    Quote Originally Posted by SolarAlternativesDesign View Post
    Anyway, my point is that after I have determined and accomplished the needed bonding at the ends of the circuit I still don't understand how the electrical continuity needs to be accomplished between sections of raceway.
    The raceway sections are mechanically connected to each other with couplings that's all that you need.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  8. #8
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    Thanks very much for clarifying!

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