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Thread: Grounding

  1. #1
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    Grounding

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    Above is a panel to be installed in a PDC (Power Distribution Center or Power House). This panel came with three separate ground bars; but with only one ground bar having a grounding electrode connection point. The two ground bars that do not have a grounding electrode point are screwed directly to the panel. Should these two ground bars be jumpered to the third ground bar or can the panel be used as the connection between these three ground bars?
    Also, is there any educational literature or videos that deal with grounding that I could use as a training tool?

  2. #2
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    I see no need for a jumper. Is this actually a GEC or an EGC?
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  3. #3
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    Quote Originally Posted by JRumsey View Post
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    Above is a panel to be installed in a PDC (Power Distribution Center or Power House). This panel came with three separate ground bars; but with only one ground bar having a grounding electrode connection point. The two ground bars that do not have a grounding electrode point are screwed directly to the panel. Should these two ground bars be jumpered to the third ground bar or can the panel be used as the connection between these three ground bars?
    Also, is there any educational literature or videos that deal with grounding that I could use as a training tool?
    As best I can tell from the photos those are just standard equipment ground bars and 1 just happens to have an optional lug for a larger conductor. Except for rare exceptions the GEC would not connect to an equipment ground bar. Is this an application that even requires a GES?

  4. #4
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    The metal enclosure electrically bonds the bus bars together. There is no need to install jumpers between them.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  5. #5
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    Quote Originally Posted by DrSparks View Post
    The metal enclosure electrically bonds the bus bars together. There is no need to install jumpers between them.
    Although there are those who feel that even though the little tiny sheet metal screw(s) are all the code requires, they are just not comfortable with that.

  6. #6
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    Quote Originally Posted by infinity View Post
    I see no need for a jumper. Is this actually a GEC or an EGC?
    But that's the thing....

    Milbank makes meters with GEC lugs inclusive in the N connection, or separate from it.

    POCO's local to me require a 'solid connection' meaning not through sheet metal

    I guess they've established a dif between 277 or 120V's and 1,000,000 volts

    ~RJ~

  7. #7
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    to expand on this a bit, am I correct on the following:

    1. If the panelboard was in a remote separate structure fed via a feeder, the GEC would have to land on the same ground bar as all the EGC's
    2. If N-G were bonded due to this being a service, the GEC would have to land on the same bar/bus as the grounded conductor.

    edit: actually not sure about #1....
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  8. #8
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    Quote Originally Posted by GoldDigger View Post
    Although there are those who feel that even though the little tiny sheet metal screw(s) are all the code requires, they are just not comfortable with that.
    The screws that are required must be sized number 10 with a minimum of 24 threads per inch. This has been evaluated by Testing Laboratories

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  9. #9
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    Quote Originally Posted by electrofelon View Post
    to expand on this a bit, am I correct on the following:

    1. If the panelboard was in a remote separate structure fed via a feeder, the GEC would have to land on the same ground bar as all the EGC's
    2. If N-G were bonded due to this being a service, the GEC would have to land on the same bar/bus as the grounded conductor.

    edit: actually not sure about #1....
    You are correct. If it is an external building fed by a feeder or a sub feeder from the main building the grounding electrode conductor would terminate on the equipment grounding bar and the neutral busbar would remain isolated from ground.

    If you were to bond the neutral to ground in the subpanel the neutral current would take parallel paths back to the service equipment possibly creating a potential difference across grounded non-current carrying surfaces

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  10. #10
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    Quote Originally Posted by DrSparks View Post
    The screws that are required must be sized number 10 with a minimum of 24 threads per inch. This has been evaluated by Testing Laboratories

    Sent from my A574BL using Tapatalk
    How come all my SqD pk xxx ground bars come with 8-32 screws?
    If you go and decide to dance with a gorilla the dance ain't over till the gorilla decides it's over.

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