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Originally Posted by Fordguy64
They want it to be engineered and signed off to make sure it’s done correctly. Don’t want to kill a lineman/woman because of your faulty backfeed system..
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Have to agree with OilPan there, there are plenty of UL1741 compliant intertie inverters available that are Not manufactured by ABB. (whoever is writing rules for the regional city power provider must be heavily invested in ABB stock) I designed my own PV systems. They're NEC compliant, and I didn't need to be a PE to make them legit, (except for the structural engineering).
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Originally Posted by ecomodded
They use engineers so want you to use one too. If we were in India or some place the hook ups would be less stringent but not dependable. Its basically the cost of doing business, a safety stamp if you will.
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I had to draw electrical 3-line diagrams to get my state certification number for my PV system in FL. It doesn't take an electrical engineer with a PE license to draw 3-line diagrams. As long as you knew what you were doing designing the PV system (i.e. understand the NEC), the state's PE looked the drawings over and either approved them, or suggested any minor modifications necessary to gain system compliance. The state PE who reviewed my system for NEC compliance, asked me if I'd ever drawn one of these systems before? I told him: No, I'm professionally licensed in two states in an unrelated highly technical field. I draw stuff in AutoCAD all day long, so drawing a 3-line diagram wasn't particularly difficult. My basic design philosophy was: show everything in the design, leave nothing to guess about, and make the electrical diagrams so simplified my nephew (in high school) could follow them to wire the system up.
If you're wondering what sorts of "minor modifications" the reviewing PE might suggest, I'll use an example: Although my 12AWG portrait trunk cable should have been fine with 20A breakers (back feeding a 200A main panel), it was suggested I de-rate them to 15A breakers for my system since I was running 10 inverters per circuit, and the two 15A backfeeds breakers kept me under the 20% backfeed limit NEC places on your main panel (in my case, a 150A panel with one 15A circuit driven from it). The panel, rack and inverter grounding, the part that folks who deal with the NEC every day typically mess up, I did fine with on my 3-line diagrams. Mike Holt's write ups on panel and system grounding were helpful.
Would my PV system have been catastrophically flawed if I had used the two 20A breakers instead of two 15A breakers? The ten 220W panels attached to ten 215W micro-inverters will only put out so much power, unless the sun moves closer... The PV generation end was already a design limitation on the system backfeed capability into my main panel.
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Originally Posted by oil pan 4
In a nut shell it's best case scenario...
They said they only have 2 other residential solar panel cogen meter users in all of the coop, but they want more.
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Maybe when your neighbors see your system, adoption will increase. I have friends and neighbors who would like to adopt PV, but right now, they're just paying the electric company the money that would be paying for their system...