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Thread: Grounding and Bonding at service?

  1. #1
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    Grounding and Bonding at service?

    Hey, I'm recently turned out and just trying to learn a thing or two in my spare time. My goal for this weekend is to learn a lot about grounding and bonding and draw out my diagrams of different scenarios so I can have them in my service van whenever I need to pull them out and refresh myself before a job. I wanted to see if I'm correct with my thinking on how to ground and bond.

    Equipment used:
    1. Meter
    2. Fusible Disconnect
    3. None fusible disconnect
    4. Main panel
    5. Sub panel

    So let's say I have a 3-phase 120/240 Delta high leg service. Let's just say the raceways are none conductive (PVC). I would make sure there is a grounding electrode conductor bonded to the neutral at the load side of the service drop. The 4 wires come down from the weather head and into the meter can. Unsure if I need a grounding electrode to earth bonded to the neutral inside the meter can? From there I pull 4 wires from the meter and into fusible disconnect. Fusible disconnect 1 has to have the ground and neutral bonded together, and a grounding electrode must go to earth. Now I pull 5 wires (adding a EGC) to a none-fusible disconnect. At the none-fusible disconnect, I bond the EGC to the ground bar and the neutral is isolated and not bonded to the metal or anything. From here I pull 5 wires to the main panel inside/outside the building. Here I bond the neutral and ground together, and also (for example) drive a ground rod and bond both to a grounding electrode. Then from main panel to sub panel, I pull my 5 wires and in this sub panel, the neutral and ground bars are NOT bonded together, and the ground bar is bonded to the frame of the panel. No Grounding electrode to earth is required here.

    Just wondering if I'm right or wrong with all this? Thanks a ton for any help or corrections you might have!

  2. #2
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    250.24(A)(1) your problem with meter base is if the connection is considered accessible, it is often not.

    250.24(B) is disconnect 2 fed directly from meter base? or from disconnect 1? 230.71(A)

    don't bond again in panel
    Last edited by Wire-Smith; 06-15-19 at 07:10 PM.

  3. #3
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    Quote Originally Posted by JasonCo View Post
    Hey, I'm recently turned out and just trying to learn a thing or two in my spare time. My goal for this weekend is to learn a lot about grounding and bonding and draw out my diagrams of different scenarios so I can have them in my service van whenever I need to pull them out and refresh myself before a job. I wanted to see if I'm correct with my thinking on how to ground and bond.

    Equipment used:
    1. Meter
    2. Fusible Disconnect
    3. None fusible disconnect
    4. Main panel
    5. Sub panel

    So let's say I have a 3-phase 120/240 Delta high leg service. Let's just say the raceways are none conductive (PVC). I would make sure there is a grounding electrode conductor bonded to the neutral at the load side of the service drop. The 4 wires come down from the weather head and into the meter can. Unsure if I need a grounding electrode to earth bonded to the neutral inside the meter can? From there I pull 4 wires from the meter and into fusible disconnect. Fusible disconnect 1 has to have the ground and neutral bonded together, and a grounding electrode must go to earth. Now I pull 5 wires (adding a EGC) to a none-fusible disconnect. At the none-fusible disconnect, I bond the EGC to the ground bar and the neutral is isolated and not bonded to the metal or anything. From here I pull 5 wires to the main panel inside/outside the building. Here I bond the neutral and ground together, and also (for example) drive a ground rod and bond both to a grounding electrode. Then from main panel to sub panel, I pull my 5 wires and in this sub panel, the neutral and ground bars are NOT bonded together, and the ground bar is bonded to the frame of the panel. No Grounding electrode to earth is required here.

    Just wondering if I'm right or wrong with all this? Thanks a ton for any help or corrections you might have!
    You never re bond the neutral after the first disconnect a.k.a Service Disconnect or the first disconnect of a Separately Derived System.
    If you don't think too good, don't think too much.

  4. #4
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    IMO the meter is where the GEC should land and the service equipment only needs a Main Bonding Jumper.

    Roger
    Moderator

  5. #5
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    Quote Originally Posted by Wire-Smith View Post
    250.24(A)(1) your problem with meter base is if the connection is considered accessible, it is often not.

    250.24(B) is disconnect 2 fed directly from meter base? or from disconnect 1? 230.71(A)

    don't bond again in panel
    Disconnect 2 is fed directly from fused disconnect 1.

    Appreciate the fast responses, giving it a good look now.

  6. #6
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    Quote Originally Posted by JasonCo View Post
    Disconnect 2 is fed directly from fused disconnect 1.

    Appreciate the fast responses, giving it a good look now.

    we appreciate you trying to learn this

  7. #7
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    Quote Originally Posted by roger View Post
    IMO the meter is where the GEC should land and the service equipment only needs a Main Bonding Jumper.

    Roger
    The utilities here will not allow the GEC to terminate in the meter enclosure.

  8. #8
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    Quote Originally Posted by packersparky View Post
    The utilities here will not allow the GEC to terminate in the meter enclosure.
    And that makes no sense.

    What lame reason do they give for not allowing it in your location?

    Roger
    Moderator

  9. #9
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    Quote Originally Posted by roger View Post
    And that makes no sense.

    What lame reason do they give for not allowing it in your location?

    Roger
    Some nonsense about not wanting a lightning strike to take our their meter. I know.......It makes no sense but what ya gonna do.

  10. #10
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    the reason here, is the accessibility. not that i agree with it, i think the sooner it grounds the grounded conductor the better. i'm not sure if they say anything about doing it at the mast.

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