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Thread: Lightning Protection Question

  1. #11
    Join Date
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    Quote Originally Posted by Dennis Alwon View Post
    Perhaps on a long run it would make sense but not on a 4' piece, IMO
    Even a 6" metallic pipe must be bonded on both ends. Lightning can cause induction that inhibits the wire's conductivity.

    It's not for conductive bonding, but for inductive bonding. More like not running a single phase in metallic conduit.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  2. #12
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    Apr 2006
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    Springfield, MA, USA
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    I am with GoldDigger on the theory about why this is an issue, so the question is one of 'what _exactly_ does NFPA 780 require?'

    Does the bond need to be done with something 'rated for lightning protection system' or is something like a split grounding bushing acceptable?

    Do you have options other than removing everything and re-doing?

    For NEC required grounding (but I don't know about NFPA 780) you have available 'split' grounding bushings which can be attached to the conduit with the wire in place, and you also have various grounding clamps available. 'Lay in lugs' are also available for connecting to wire without having to cut it.

    -Jon

  3. #13
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    Yes, you can use a split grounding bushing, and even a jumper to connect the bushing to the wire.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  4. #14
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    May 2011
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    4,577
    Quote Originally Posted by LarryFine View Post
    Yes, you can use a split grounding bushing, and even a jumper to connect the bushing to the wire.
    I'm imagining the rigid nipples threaded into female PCV connectors and seeing the difficulty he has. Nowhere to install that bushing.

    I'm assuming these are the lightning down conductors and not grounding electrode conductors. In which case, anybody got a copy of 780? NEC requirements for GECs are irrelevant I think.

  5. #15
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    Quote Originally Posted by jaggedben View Post
    I'm imagining the rigid nipples threaded into female PCV connectors and seeing the difficulty he has. Nowhere to install that bushing.

    I'm assuming these are the lightning down conductors and not grounding electrode conductors. In which case, anybody got a copy of 780? NEC requirements for GECs are irrelevant I think.
    Same, 4.4.2
    "Electricity is really just organized lightning." George Carlin


    Derek

  6. #16
    Join Date
    Sep 2018
    Location
    Winston-Salem, NC
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    All-
    Jumper is exactly right in his description of the system with the female adapter changed to a RIGID coupling. I do have a workaround that the UL inspector said would be acceptable. Our RIGID nipples are attached to the metal decking of the roof with a blank 4x11 cover and lock rings on either side of the decking. The inspector said that would suffice for the bonding, because of all of the other bonding (roof & ground loop/building steel). Maybe he's letting us slide a little, but I consider this a lesson learned.

  7. #17
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    Mar 2003
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    Quote Originally Posted by Supersteele21 View Post
    All-
    Jumper is exactly right in his description of the system with the female adapter changed to a RIGID coupling. I do have a workaround that the UL inspector said would be acceptable. Our RIGID nipples are attached to the metal decking of the roof with a blank 4x11 cover and lock rings on either side of the decking. The inspector said that would suffice for the bonding, because of all of the other bonding (roof & ground loop/building steel). Maybe he's letting us slide a little, but I consider this a lesson learned.
    Sounds pretty weak to me, if bond to building steel is ok you could still use waterpipe ground clamps. Cut the pvc out and split bolt. Sounds like someone is trying to work with you, but a 4sqr. Cover ? Trek screwed to the roof deck? No.

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