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Double inverters - Need dedicated PV pnlbd?

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    Double inverters - Need dedicated PV pnlbd?

    If I'm using two inverters, do I need a dedicated (no other loads) PV panel or can I just have 2 separate load side breakers in the main service panel?

    Thanks

    #2
    In my opinion there's no rule against multiple breakers in the main service panel. I've seen one or two people in the forum say that they think the code rule for a 'dedicated' breaker requires all sources to be combined first, but I've never seen this enforced by an AHJ based on that rule.

    There may be practical limitations, such as how many breakers you can put on the 'opposite end' if using the 120% rule. Sometimes the right quad breakers aren't available.

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      #3
      Originally posted by jaggedben View Post
      In my opinion there's no rule against multiple breakers in the main service panel. I've seen one or two people in the forum say that they think the code rule for a 'dedicated' breaker requires all sources to be combined first, but I've never seen this enforced by an AHJ based on that rule.

      There may be practical limitations, such as how many breakers you can put on the 'opposite end' if using the 120% rule. Sometimes the right quad breakers aren't available.
      True, but some AHJ's will not allow you to have more than one point of interconnection for PV.

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        #4
        I’d say common practice is to combine before a single breaker but there’s nothing disallowing multiple load side backfed breakers.


        Sent from my iPhone using Tapatalk

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          #5
          Originally posted by pcanning87 View Post
          I’d say common practice is to combine before a single breaker but there’s nothing disallowing multiple load side backfed breakers.


          Sent from my iPhone using Tapatalk
          Nothing but maybe the rules of the AHJ. Ask them. Oh, and they may get picky about that "other end of the busbar" business.
          Last edited by ggunn; 10-14-19, 06:47 PM.

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            #6
            Originally posted by designer82 View Post
            If I'm using two inverters, do I need a dedicated (no other loads) PV panel or can I just have 2 separate load side breakers in the main service panel?

            Thanks
            There are advantages to combining the inverter outputs first, and then sending them to the interconnection. For instance, if your program requires a production meter, or if your utility requires an outside open blade switch, it means fewer of these pieces of equipment. But it is not an NEC requirement. You can interconnect two inverters at separate branch breakers on the same panelboard, provided you meet one of the busbar interconnection rules in 705.12.

            Others have mentioned the "opposite end of the bus" issue, as there are only two positions for full circuit connections (i.e. 3-pole on a 3-phase or 2-pole on a split phase) at the exact opposite end of the bus on a typical panelboard. Therefore, you'd likely have to combine in advance of interconnection if you had more than two inverters. I see no greater physical consequence to interconnecting on 3x 20A breakers at the opposite end of a bus through the 120% rule, than there would be with a single 60A breaker for the same three inverters. But it's the principle of meeting the strict definition of "opposite end", that would leave it open to interpretation to not allow all 3 breakers at the opposite end.

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