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Thread: GEC Run Through CT Cabinet

  1. #1
    Join Date
    Oct 2015
    Location
    York, PA
    Posts
    61

    GEC Run Through CT Cabinet

    I'm working on a design for a building renovation and the existing grounding is a bit different than I've come across before. The building is being gutted to steel, and the only electrical gear that is remaining and getting reused is the meterbase, CT cabinet, and main disconnect. The CT cabinet and main disconnect are located in the basement of the building.

    The sketch below shows how the existing grounding electrode conductor runs from building steel, through the CT cabinet, and (presumably) to the neutral bar in the main disconnect. You can see the GEC go from building steel into the CT cabinet, but I haven't seen what happens to it in inside the cabinet. Inside the main disconnect, you can see what appears to be the GEC entering with one of the incoming sets and land on the neutral bar.

    Click image for larger version. 

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    Click image for larger version. 

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    Does this grounding make anyone else uncomfortable? I've never seen the GEC run through the utility CT cabinet before. I can't find any code it would violate as long as the conductor is continuous through the CT cabinet and the building steel qualifies as a grounding electrode. However, I haven't seen inside the CT cabinet and I don't know much about the building frame/foundation, so I feel a little uneasy about leaving things the way they are.

    Here's my plan for improving the installation:
    1. Install a ground bar in the service disconnect so EGCs can be run with the new outgoing feeder.
    2. Install two ground rods 6' apart and bond to building steel (to ensure building steel qualifies as grounding electrode).
    3. Bond sprinkler piping and domestic water piping to building steel (within 5' of the piping entering the building).
    4. Install main bonding jumper between the neutral bar and ground bar in the main disconnect.


    I'm just not sure then if I should leave the existing GEC in place, or if I should involve the utility company to get it removed and install a new GEC from building steel to main disconnect ground bar.

    Thoughts? What would you do in this situation? Is this the utility company's call?
    Last edited by Sunny_92; 06-13-18 at 12:03 PM.

  2. #2
    Join Date
    Feb 2003
    Location
    Bremerton, Washington
    Posts
    7,837
    Our POCO has very specific drawings and standards for metering and CT cabinets, they don't allow a GEC in a CT can.
    NEC requires the GEC to be bonded at each end when in metallic conduit, this is a lot of work much easier to run GEC in PVC or exposed.
    Moderator-Washington State
    Ancora Imparo

  3. #3
    Join Date
    Oct 2015
    Location
    York, PA
    Posts
    61
    Quote Originally Posted by tom baker View Post
    Our POCO has very specific drawings and standards for metering and CT cabinets, they don't allow a GEC in a CT can.
    NEC requires the GEC to be bonded at each end when in metallic conduit, this is a lot of work much easier to run GEC in PVC or exposed.
    Good point, I forgot about that. Looks like that would be one existing code violation.

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