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Thread: Gas station grounding?

  1. #11
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    Fair enough. Yes I could be more technical with my terms. I also noticed I only used "grounding" in the topic and not "grounding and bonding" since we are discussing both really. My apologies. I will read through the language posted and go from there.

    Thank you very much for the input.

  2. #12
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    Quote Originally Posted by rbalex View Post
    Start by reading Section 250.4 and understanding the implications of Subsections 250.4(A)(3),(4) and (5) and 250.4(B)(2),(3) and (4). Even small, usually inconsequential, "(n)ormally non-current-carrying electrically conductive materials ..." can become energized and need an effective ground-fault current path or, in the case of ungrounded systems, simply a fault path. Whether those small, usually inconsequential, normally non-current-carrying electrically conductive materials are "likely to become energized" may be a subject of some debate but Subsections 250.4(A)(3) and 250.4(B)(2) would strongly suggest that simply enclosing electrical conductors is a sufficient concern and it doesn't even matter whether it's in a classified location or not; it's simply a general rule.
    A locknut inside and outside entering a bonded metal enclosure is sufficient to bond the metal raceway in all other applications though, what makes this so different in this application? Especially if you transitioned from non metallic raceway before emerging from below grade?

    You may very well have raceways right next to them that don't go to classified areas. At a C store this may be signs, vending machines, vacuums, air stations, etc. that are away from the building.

    You are not in a classified area anymore, you may have a seal fitting at this location because it is the first place to put one on the non classified side of the boundary.

  3. #13
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    Quote Originally Posted by kwired View Post
    A locknut inside and outside entering a bonded metal enclosure is sufficient to bond the metal raceway in all other applications though, what makes this so different in this application? Especially if you transitioned from non metallic raceway before emerging from below grade?

    You may very well have raceways right next to them that don't go to classified areas. At a C store this may be signs, vending machines, vacuums, air stations, etc. that are away from the building.

    You are not in a classified area anymore, you may have a seal fitting at this location because it is the first place to put one on the non classified side of the boundary.
    Yeah, so?

    It isn't relevant to the OP's question and I've actually addressed these issues in my previous posts in this thread.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  4. #14
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    Quote Originally Posted by rbalex View Post
    Yeah, so?

    It isn't relevant to the OP's question and I've actually addressed these issues in my previous posts in this thread.
    Sorry but I failed to see anything that improves the conditions that actually are within the hazardous location, especially if there is a transition from non metallic raceway involved.

  5. #15
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    I'm not sure there would be anything pertaining exactly to if the underground is pvc, and only the first ten feet on each end is rmc. Still, that portion of rmc on each end shall be bonded. Going into the dispenser is usually bonded by having 5 threads engaged. On the gutter end, that portion of rmc still needs to be bonded. I wonder if a Myers hub would provide adequate bonding rather than a bonding bushing on the inside of the gutter?

    Just to be clear, there is a grounding conductor in these raceways.

  6. #16
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    Quote Originally Posted by Dr Duke View Post
    I'm not sure there would be anything pertaining exactly to if the underground is pvc, and only the first ten feet on each end is rmc. Still, that portion of rmc on each end shall be bonded. Going into the dispenser is usually bonded by having 5 threads engaged. On the gutter end, that portion of rmc still needs to be bonded. I wonder if a Myers hub would provide adequate bonding rather than a bonding bushing on the inside of the gutter?

    Just to be clear, there is a grounding conductor in these raceways.
    I guess I should have mentioned in my first post (Post #2) that the wire EGC that would otherwise be required by a PVC installation makes a fine bonding conductor. I did sorta hint at it in Post #5; i.e., EGCs should be called Electrical Bonding Conductors (EBCs). It also accounts for overlooking many double-locknut and locknut-bushing connections as mentioned by augie47 in Post #8. Remember, Section 501.30(A) [or 502.30(A) or 503.30(A)] doesn't actually prohibit them; it just says they aren't to be depended on as bonds in classified locations.

    Edit Add: Some Myers hubs are listed as grounding connectors.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  7. #17
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    Yes, definitely. I always have an equipment grounding conductor in this application, whether full rmc or a combination of both rmc and pvc.

    Thanks for the clarification on my questions rbalex.

  8. #18
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    Quote Originally Posted by rbalex View Post
    I guess I should have mentioned in my first post (Post #2) that the wire EGC that would otherwise be required by a PVC installation makes a fine bonding conductor. I did sorta hint at it in Post #5; i.e., EGCs should be called Electrical Bonding Conductors (EBCs). It also accounts for overlooking many double-locknut and locknut-bushing connections as mentioned by augie47 in Post #8. Remember, Section 501.30(A) [or 502.30(A) or 503.30(A)] doesn't actually prohibit them; it just says they aren't to be depended on as bonds in classified locations.

    Edit Add: Some Myers hubs are listed as grounding connectors.
    That helps answer what I was asking about. Thanks.

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