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More is better, right???

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  • More is better, right???

    My 8.8 kw GT system is working great! It cut my bill by about 60% so far. I am still working on reducing my consumption but the two electric cars are not helping in my all electric house. I am looking to add more panels and another inverter to increase my production and max out my roof area. My question is do they just add another breaker in the main service panel for the new panels? Can you have two separate backfeed breakers in the main panel from different separate systems? Will they have to put another PV meter, master cutoff, etc. for the new system? The new panels are on the far side of the house and will be the longest runs. Is it possible to backfeed the new system at the sub panel? The sub panel is located on that far side of the house and would be a short run.

  • #2
    Originally posted by Texican View Post
    My 8.8 kw GT system is working great! It cut my bill by about 60% so far. I am still working on reducing my consumption but the two electric cars are not helping in my all electric house. I am looking to add more panels and another inverter to increase my production and max out my roof area. My question is do they just add another breaker in the main service panel for the new panels? Can you have two separate backfeed breakers in the main panel from different separate systems? Will they have to put another PV meter, master cutoff, etc. for the new system? The new panels are on the far side of the house and will be the longest runs. Is it possible to backfeed the new system at the sub panel? The sub panel is located on that far side of the house and would be a short run.
    You can put any number of backfed breakers into a panel, as long as they are all at the opposite end from the main breaker (no load breakers located in between the PV breakers.)
    And you can put the backfeed into a subpanel, or some to subpanel and some to main. If you connect the PV to a subpanel, then the breaker in the main panel which feeds that subpanel must be at the opposite end of the bus from the main, and closer to the main than any PV-only breakers already in the main panel.
    And you will have to meet the 120% rule sizing for both panels and for the wiring from main panel to subpanel. That latter factor can make it difficult in some cases to use an existing supanel with the existing feeder wire if your AHJ (inspector) takes issue with its size and tries to apply the 120% rule to that feeder wire. (Essentially saying that the sum of the feed breaker rating and the PV backfeed rating in the subpanel cannot be more than 120% of the amp rating of the feeder wire.)

    Applying the 120% rule correctly is often difficult for the average electrician and the average inspector and a great deal of discussion has taken place on this and other forums on that subject.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

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    • #3
      Inetdog,

      I am still reading posts on this and several other forums trying to get as much info as I can before making my next move. A/C coupling, battery backup, parallel power, priority power--so much to digest. Thanks for your input.

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