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Thread: Meyers Hub

  1. #1
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    Meyers Hub

    Is a Meyers hub suitable for connecting metallic service raceway to an enclosure and be compliant for bonding? I know it is for a metallic feeder conduit, but I am unclear if this is OK for a service raceway. What say the UL White book?

  2. #2
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    Not sure about the White book but I would guess that it would need a bonding locknut, bonding bushing or bonding wedge.
    Rob

    Chief Moderator

    All responses based on the 2011 NEC unless otherwise noted

  3. #3
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    From the UL Book


    Grounding and Bonding Hubs ? Grounding and bonding hubs are
    Listed hubs (see DWTT) provided with a Listed grounding or bonding
    locknut. They serve in a manner similar to grounding and bonding bushings
    except they are only for use with threaded rigid metal and intermediate
    metal conduit. Grounding hubs provide the electrical continuity
    required by NEC 250.92 at service equipment and the electrical continuity
    required by NEC 250.97 for circuits rated over 250 V.

  4. #4
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    Quote Originally Posted by infinity View Post
    Not sure about the White book but I would guess that it would need a bonding locknut, bonding bushing or bonding wedge.
    How would one put a standard bonding locknut, bonding bushing or bonding bushing on a myers hub?
    I know that myers hubs are available with a nut that includes a grounding lug, but it is not clear to me that this in and of itself is the only thing makes them suitable for bonding a metallic service raceway. The reason I say this is many think that a hub creates a "threaded opening" that is suitable for services. But if you use that logic, why do they make them available with the locknut that includes a ground lug?

  5. #5
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    Quote Originally Posted by Dennis Alwon View Post
    From the UL Book
    Oh gee, the UL White Book language...clear as mud. Does this mean that there are 2 types of hub? One is the normal one we usually see with just a nut inside and one that has a ground lug and that makes it suitable for metallic service raceway bonding?

  6. #6
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    Quote Originally Posted by texie View Post
    Oh gee, the UL White Book language...clear as mud. Does this mean that there are 2 types of hub? One is the normal one we usually see with just a nut inside and one that has a ground lug and that makes it suitable for metallic service raceway bonding?
    My guess is they are both the same hub but equipped with different locknuts. I have seen ads or other publications mentioning the ones with the ground lug and have asked supplier if they had any of them before... they had no idea what I was talking about, so apparently nobody uses them around here anyway.

  7. #7
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    Quote Originally Posted by kwired View Post
    My guess is they are both the same hub but equipped with different locknuts. I have seen ads or other publications mentioning the ones with the ground lug and have asked supplier if they had any of them before... they had no idea what I was talking about, so apparently nobody uses them around here anyway.
    Yes, they are the same hub and all you have to do is change the nut for one that has the ground lug. In my area the nut with the ground lug is readily available. But my question is, is that nut with a ground lug what makes it suitable for bonding a metallic service raceway?
    Would your AHJ accept one without the ground lug (and bonding jumper) as bonding for a metallic service raceway?
    Sorry if I seem to be harping on this, but this has come up a lot for me recently. This just not seem clear to me.
    Bottom line, is a myers hub without the ground lug suitable for bonding of a metallic service raceway?

  8. #8
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    Quote Originally Posted by kwired View Post
    My guess is they are both the same hub but equipped with different locknuts. I have seen ads or other publications mentioning the ones with the ground lug and have asked supplier if they had any of them before... they had no idea what I was talking about, so apparently nobody uses them around here anyway.
    Like these?

    Last edited by Little Bill; 08-07-13 at 10:45 PM.
    If you aim at nothing, you will hit it every time!

  9. #9
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    Quote Originally Posted by texie View Post
    Yes, they are the same hub and all you have to do is change the nut for one that has the ground lug. In my area the nut with the ground lug is readily available. But my question is, is that nut with a ground lug what makes it suitable for bonding a metallic service raceway?
    Would your AHJ accept one without the ground lug (and bonding jumper) as bonding for a metallic service raceway?
    Sorry if I seem to be harping on this, but this has come up a lot for me recently. This just not seem clear to me.
    Bottom line, is a myers hub without the ground lug suitable for bonding of a metallic service raceway?
    I would sure hope it is, otherwise what is the ground lug really for? The other style without the lug is listed for grounding purposes otherwise.

    That said, I really can't recall ever using a myers hub on a service raceway. If entering a meter socket or a 3R breaker panel I usually am entering via bolt on hubs, but there are always those cases where something has to be different, I just can't recall any where I have used a myers hub on a service raceway.

  10. #10
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    Quote Originally Posted by Little Bill View Post
    Like these?

    I was editing when there were more posts and thought it might have gotten past some before seeing it.
    If you aim at nothing, you will hit it every time!

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