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Do you need a disconnect at a ground-mounted array?

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    Do you need a disconnect at a ground-mounted array?

    Is there any code requirement that states you need a PV disconnect at the location of a ground mount? Or can the disconnect be remote next to the inverters and a plaque showing where it is at the ground mount?

    #2
    I would say no, you don't need one.

    Comment


      #3
      Originally posted by ryangittens View Post
      Is there any code requirement that states you need a PV disconnect at the location of a ground mount? Or can the disconnect be remote next to the inverters and a plaque showing where it is at the ground mount?
      If the inverters are remote from the array, then no, I don't think you have to have a disco at the array, though it might be a good idea. You don't need a placard, either; that's for AC sources.

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        #4
        The outside feeder is covered under 225 (however a disco is not required at the supply end).
        A DC disconnect is required where it first enters the structure it supplies 225.32.
        I personally would put one on the pole, but don't see anything other than 690.13(A) requiring you to put one there.
        Comments based on 2017 NEC unless otherwise noted.

        Comment


          #5
          Originally posted by tortuga View Post
          The outside feeder is covered under 225 (however a disco is not required at the supply end).
          A DC disconnect is required where it first enters the structure it supplies 225.32.
          Most inverters have integrated DC disconnects, so they have that covered, if it's even required in this case. If the inverters are on an outside wall, the DC never enters the building.
          Originally posted by tortuga View Post
          I personally would put one on the pole, but don't see anything other than 690.13(A) requiring you to put one there.
          So would I.

          Comment


            #6
            Originally posted by tortuga View Post
            The outside feeder is covered under 225 (however a disco is not required at the supply end).
            A DC disconnect is required where it first enters the structure it supplies 225.32.
            I personally would put one on the pole, but don't see anything other than 690.13(A) requiring you to put one there.
            If AC were run out to the ground mount, I would say per 225 we might need a disconnect. I say might because of the revised definition of "structure" and "equipment" is now not a structure. It's a bit gray to me. Its really just academic tho as most inverters have AC disconnects, and a combiner panel will usually have less than 6 throws if MLO.

            Just for completeness, one thing I have done is use 230.40 exception 3 to serve a ground mount. In that case of course there needs to be service disconnect.
            Ethan Brush - East West Electric. NY, WA. MA

            "You can't generalize"

            Comment


              #7
              Originally posted by electrofelon View Post

              If AC were run out to the ground mount, I would say per 225 we might need a disconnect. I say might because of the revised definition of "structure" and "equipment" is now not a structure. It's a bit gray to me. Its really just academic tho as most inverters have AC disconnects, and a combiner panel will usually have less than 6 throws if MLO.
              The six handle rule does not apply to a combiner, AC or DC, MLO or no, as long as it doesn't connect directly to the service conductors with no disco between it and them.

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                #8
                Originally posted by ggunn View Post

                The six handle rule does not apply to a combiner, AC or DC, MLO or no, as long as it doesn't connect directly to the service conductors with no disco between it and them.
                Hmmm, well the 6 handle rule doesn't apply to the article 690 disconnects, but would apply to any article 225 or 230 requirements. Do you concur with that statement? Is there a way to NOT classify the AC conductors going to a combiner panelboard at a ground mount as a article 225 feeder?
                Ethan Brush - East West Electric. NY, WA. MA

                "You can't generalize"

                Comment


                  #9
                  If we are talking DC, I think it's doubtful we have any 'feeders'. 690 defines DC circuits in ways that exclude all parts of other circuits that are definitely feeders, and Chapter 6 takes precedence over Chapter 2.

                  If we are talking AC, it's a little more complicated, as there is no way to make sense of the definition of inverter output circuits without acknowledging that parts of it can also be service conductors or feeders at the same time. It would be hard to argue against an AHJ who wants to enforce 225, especially since 225.32 contains two article-specific exceptions that aren't for 690.

                  Comment


                    #10
                    Originally posted by electrofelon View Post

                    Hmmm, well the 6 handle rule doesn't apply to the article 690 disconnects, but would apply to any article 225 or 230 requirements. Do you concur with that statement? Is there a way to NOT classify the AC conductors going to a combiner panelboard at a ground mount as a article 225 feeder?
                    If an MLO AC combiner is connected directly to service conductors, then the number of handles is of course governed by the six handle rule, but if there is a disco between it and the service conductors, then there is only one handle. I have PV systems in place with 30 or more inverters (one has 42) feeding MLO AC combiners in line side interconnections, but they all have a disco between the combiner and the service, so there is only one handle.

                    Comment


                      #11
                      Originally posted by jaggedben View Post
                      If we are talking DC, I think it's doubtful we have any 'feeders'. 690 defines DC circuits in ways that exclude all parts of other circuits that are definitely feeders, and Chapter 6 takes precedence over Chapter 2.

                      If we are talking AC, it's a little more complicated, as there is no way to make sense of the definition of inverter output circuits without acknowledging that parts of it can also be service conductors or feeders at the same time. It would be hard to argue against an AHJ who wants to enforce 225, especially since 225.32 contains two article-specific exceptions that aren't for 690.
                      I agree. Similarly, as I have complained in the past, it's also not always possible to differentiate between a supply side connection and a load side to a 230.40 exception 2 install
                      Ethan Brush - East West Electric. NY, WA. MA

                      "You can't generalize"

                      Comment

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