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250.24(A)(1) Bonding the grounded conductor.

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    250.24(A)(1) Bonding the grounded conductor.

    We work with multiple POCO's. One will have you bond the grounded conductor in the meter can, another will forbid it. My question is, if we are asked to bond the grounded conductor inside the meter can, are we still obligated to bond the grounded conductor at the main disconnect? Are we permitted to do it? Is it optional? 250.24(A)(1) seems to say it can be done at either location, to and including the the terminal or bus at the main. Am I interpreting that correctly to assume I need to still bond the neutral to the GEC at the main service disconnect?
    Last edited by AV8R; 05-09-18, 03:55 PM.

    #2
    Most meter sockets are designed so that they automatically bond the grounded conductor due to the neutral "buss" being mounted to the can itself. 250.24 still requires you bond the service disconnect. Depending on the wiring method you may actually set up a "objectionable" current but this is accepted by practice.

    Your question seems to be discussing the connection of a grounding electrode, not bonding. Unless POCO has a rule, that connection can be made at the meter or service disconnect. IMHO, the connection to a particular electrode should only originate at one of those locations to prevent objectionable flow (other electrodes can connection to the other location)
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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      #3
      Originally posted by augie47 View Post
      Most meter sockets are designed so that they automatically bond the grounded conductor due to the neutral "buss" being mounted to the can itself. 250.24 still requires you bond the service disconnect. Depending on the wiring method you may actually set up a "objectionable" current but this is accepted by practice.

      Your question seems to be discussing the connection of a grounding electrode, not bonding. Unless POCO has a rule, that connection can be made at the meter or service disconnect. IMHO, the connection to a particular electrode should only originate at one of those locations to prevent objectionable flow (other electrodes can connection to the other location)
      I probably didn't ask the question correctly. We were asked by POCO to attach a grounding electrode to the meter can from a ground rod, and the neutral is also bonded to the meter can at that point. In addition, we still installed all of our grounding at the main disconnect; water main, building steel, concrete encased electrode, ETC. My foreman opted to leave out the bonding jumper between the neutral bar and the equipment ground, just like we would at a sub panel. I asked him to install the jumper at the main, after I inspected the panel. Now I'm second guessing myself and looking for confirmation or correction.
      Thanks!

      Comment


        #4
        Originally posted by AV8R View Post
        I probably didn't ask the question correctly. We were asked by POCO to attach a grounding electrode to the meter can from a ground rod, and the neutral is also bonded to the meter can at that point. In addition, we still installed all of our grounding at the main disconnect; water main, building steel, concrete encased electrode, ETC. My foreman opted to leave out the bonding jumper between the neutral bar and the equipment ground, just like we would at a sub panel. I asked him to install the jumper at the main, after I inspected the panel. Now I'm second guessing myself and looking for confirmation or correction.
        Thanks!
        You were good up to the bold part. You need an MBJ at the panel.
        Rob

        Moderator

        All responses based on the 2014 NEC unless otherwise noted

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          #5
          Originally posted by infinity View Post
          You were good up to the bold part. You need an MBJ at the panel.
          That's what I thought, thanks. No matter how many grounding Continuing Ed classes I've taken, I feel like there's so much still to learn about a seemingly small subject, bonding and grounding.

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            #6
            Originally posted by AV8R View Post
            That's what I thought, thanks. No matter how many grounding Continuing Ed classes I've taken, I feel like there's so much still to learn about a seemingly small subject, bonding and grounding.
            I read 250.64(A)(1) and GEC connection has to be accessible location. Utility meter can are locked by the utility and not accessible. Utility may be have special type of enclosure where GEC accessible otherwise GEC meter can wont be accessible.

            Sent from my SM-G935U using Tapatalk

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              #7
              Originally posted by hhsting View Post
              I read 250.64(A)(1) and GEC connection has to be accessible location. Utility meter can are locked by the utility and not accessible. Utility may be have special type of enclosure where GEC accessible otherwise GEC meter can wont be accessible.
              Not true, this is a common believed myth, a meter can is accessible or you could not have any connections inside it .

              Roger
              Moderator

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                #8
                Around here POCO locks the meter can so that no one steal power and meter is only accesible to POCO. I guess every POCO is different.

                Sent from my SM-G935U using Tapatalk

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                  #9
                  Originally posted by hhsting View Post
                  Around here POCO locks the meter can so that no one steal power and meter is only accesible to POCO. I guess every POCO is different.
                  That doesn't change the fact that it is still accessible, just an inconvenience to have to wait for them to get there.

                  Roger
                  Moderator

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                    #10
                    Defintion NEC accessible: capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to actions such as to use tools, to climb over or remove obstacles, or to resort to portable ladders and so forth.

                    One cannot reach quickly have to wait for POCO.

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                      #11
                      Originally posted by hhsting View Post
                      Defintion NEC accessible: capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to actions such as to use tools, to climb over or remove obstacles, or to resort to portable ladders and so forth.

                      One cannot reach quickly have to wait for POCO.
                      Go back and read Accessible (as applied to wiring methods), you're reading the wrong definition.

                      Roger
                      Moderator

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                        #12
                        Originally posted by AV8R View Post
                        We work with multiple POCO's. One will have you bond the grounded conductor in the meter can, another will forbid it. My question is, if we are asked to bond the grounded conductor inside the meter can, are we still obligated to bond the grounded conductor at the main disconnect? Are we permitted to do it? Is it optional? 250.24(A)(1) seems to say it can be done at either location, to and including the the terminal or bus at the main. Am I interpreting that correctly to assume I need to still bond the neutral to the GEC at the main service disconnect?
                        I think the confusion is you are talking about two different things: one is the connection of the GEC to the grounded conductor, the other is the MBJ - the connection of the EGC bus to the grounded conductor.
                        Ethan Brush - East West Electric. NY, WA. MA

                        "You can't generalize"

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                          #13
                          Accessible: admitting close approach; not guarded by locked doors, elevation, or other effective means.

                          GEC connection applies to meter equipment enclosure.

                          Sent from my SM-G935U using Tapatalk

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                            #14
                            Originally posted by AV8R View Post
                            I probably didn't ask the question correctly. We were asked by POCO to attach a grounding electrode to the meter can from a ground rod, and the neutral is also bonded to the meter can at that point. In addition, we still installed all of our grounding at the main disconnect; water main, building steel, concrete encased electrode, ETC. My foreman opted to leave out the bonding jumper between the neutral bar and the equipment ground, just like we would at a sub panel. I asked him to install the jumper at the main, after I inspected the panel. Now I'm second guessing myself and looking for confirmation or correction.
                            Thanks!
                            You did the right thing tell him to install the main bonding jumper. Having EGCs not ultimately connected to the grounded conductor is in my judgement a hundred times more dangerous than having the wrong location for connection of a grounding electrode conductor.

                            Comment


                              #15
                              Originally posted by hhsting View Post
                              Accessible: admitting close approach; not guarded by locked doors, elevation, or other effective means.

                              GEC connection applies to meter equipment enclosure.

                              Sent from my SM-G935U using Tapatalk
                              You're still reading the wrong definition, read the one I pointed you to. After that if you still can't grasp it tell me why the other conductors landed in the meter can don't need to be accessible.

                              Just to help you out a little, most commercial buildings (hospitals, shopping centers, schools, etc...) have the electrical rooms locked which takes you away from the definition for Accessible which mean you need to look at Accessible (as applied to wiring methods)

                              Roger
                              Moderator

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