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  1. #1
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    Default Bonding screw ?? Here I go Again

    I have a main service panel, 200 amp Square D panel, the grounds and neutrals are on there own separate bars. Should the bonding screw (green screw) be screwed into the panel enclosure ? I hope I said that correctly.

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  2. #2
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    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Sam Morris View Post
    I have a main service panel ...
    .
    .
    .
    Should the bonding screw (green screw) be screwed into the panel enclosure ?
    Trusting that the panel with the main is indeed the service equipment (basically, that is the first disconnect after the meter and shut the entire structure off), then, yes, the green bonding screw in the neutral terminal bar should be screwed into its threaded hole in the back of the enclosure.

    The separate grounding terminal bars have the grounds bonded to the enclosure, which grounds the enclosure, so now what is left to do is to bond the neutral to the enclosure - and that is what that green bonding screw does.

    However ... that multiple tap of that main green grounding conductor and the bare conductor is not right - that terminal is most likely rated for one and only one conductor, and for terminals which are rated for two grounding conductors, the rating will be (almost always will be) for two of the same size conductors.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  3. #3
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    Default Re: Bonding screw ?? Here I go Again

    Jut remembered something important, this is NOT the main service disconnect it was located on the side of the house.


  4. #4
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    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Jerry Peck View Post
    Trusting that the panel with the main is indeed the service equipment (basically, that is the first disconnect after the meter and shut the entire structure off), then, yes, the green bonding screw in the neutral terminal bar should be screwed into its threaded hole in the back of the enclosure.
    Quote Originally Posted by Sam Morris View Post
    Jut remembered something important, this is NOT the main service disconnect it was located on the side of the house.
    That is a VERY IMPORTANT thing you just remembered ... ... in which case that green bonding screw should NOT be screwed into the back of the enclosure.

    So, that disconnect is just serving as a "panel main" in that it shuts the panel off - good safety feature not required by code, but a good safety feature.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  5. #5
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    Default Re: Bonding screw ?? Here I go Again

    What JP said. But he forgot to call it a sub panel.

    Clue #1, Neat and tidy professional work, #2, Neutrals and ground carefully separated in the USA, where that is not required at the main disconnect, #3, a part left over but left for the inspector to find.
    It is a remote distribution panel.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  6. #6
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    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Jerry Peck View Post
    However ... that multiple tap of that main green grounding conductor and the bare conductor is not right - that terminal is most likely rated for one and only one conductor, and for terminals which are rated for two grounding conductors, the rating will be (almost always will be) for two of the same size conductors.
    In addition to the above, something I keep going back to in those photos ... rather, something NOT in those photos ... something which might be there but is not shown.

    The feeder conductors are shown as two conductors on the ungrounded conductor main terminals and one conductor on the grounded conductor main terminal ... but where is the groundING conductor which is run with - supposed to be run with - those feeder conductors?

    Is that green ground conductor it? Or that bare ground conductor? Or was the conduit the conductors are run in metallic and is serving as the ground conductor? And, if neither the green ground conductor or the bare conductor are that conductor ... what are they for?

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  7. #7
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    Default Re: Bonding screw ?? Here I go Again

    I am really bothered by something here and maybe it is the magic of photography but is the middle wire smaller ? second issue I have is we have a three phase panel (doubt) or the neutral is not identified by having white tape on the end

    Looks like someone did a nice neat job - I just like to see wires properly identified


  8. #8
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    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Dwight Doane View Post
    I am really bothered by something here and maybe it is the magic of photography but is the middle wire smaller ?
    Yes it is.

    Decades ago, as I recall, that used to be permitted automatically - the neutral used to be permitted to be two sizes smaller as it only carried the unbalanced current.

    Then along came harmonics and the realization that the neutral could actually be carrying much more current than previously thought.

    (Added with edit: Now, one must do a calculation which supports installing a neutral which is smaller than the hot conductors.)

    second issue I have is we have a three phase panel (doubt) or the neutral is not identified by having white tape on the end
    Yep.

    I was wondering when someone would mention that the neutral conductor was not re-identified to white.

    Last edited by Jerry Peck; 02-27-2015 at 03:33 PM. Reason: see (Added with edit: ... ) part
    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  9. #9
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    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Sam Morris View Post
    I have a main service panel, 200 amp Square D panel, the grounds and neutrals are on there own separate bars. Should the bonding screw (green screw) be screwed into the panel enclosure ? I hope I said that correctly.
    It is always wise to include the reason(s) why a code requirement exsists.... inquiring minds?
    Bonding the ungrounded conductor down stream, or after the service disconnect, will result in the unbalanced load to Davide and run on the grounding (earth) conductor also.

    - - - Updated - - -

    Quote Originally Posted by Sam Morris View Post
    I have a main service panel, 200 amp Square D panel, the grounds and neutrals are on there own separate bars. Should the bonding screw (green screw) be screwed into the panel enclosure ? I hope I said that correctly.
    It is always wise to include the reason(s) why a code requirement exsists.... inquiring minds?
    Bonding the ungrounded conductor down stream, or after the service disconnect, will result in the unbalanced load to Davide and run on the grounding (earth) conductor also.


  10. #10
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    Dec 2014
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    CO
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    Default Re: Bonding screw ?? Here I go Again

    Definitely no screw. How about all of the doubled neutral wires, they should each be under their own lug

    - - - Updated - - -

    Definitely no screw. How about all of the doubled neutral wires, they should each be under their own lug


  11. #11
    Robin Wells's Avatar
    Robin Wells Guest

    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Dwight Doane View Post
    I am really bothered by something here and maybe it is the magic of photography but is the middle wire smaller ? second issue I have is we have a three phase panel (doubt) or the neutral is not identified by having white tape on the end

    Looks like someone did a nice neat job - I just like to see wires properly identified

    I agree middle conductor looks smaller. But is not a three phase panel, middle goes down and then across to the neutral bus bars. Now neutral should have white tape on it. (however if it were three phase really should have red and blue tape as well)


  12. #12
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    st. louis, mo
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    Default Re: Bonding screw ?? Here I go Again

    Quote Originally Posted by Robin Wells View Post
    I agree middle conductor looks smaller. But is not a three phase panel, middle goes down and then across to the neutral bus bars. Now neutral should have white tape on it. (however if it were three phase really should have red and blue tape as well)
    There are too many things wrong with this panel. Also if it is mounted on the side of the house, why is it not a rain tight panel. There are open screw holes shown in the back of the panel.


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