Supratachophobia
Member
- Location
- Columbus, Ohio
Thanks upfront for a great forum that's already been helpful via the search function.
We are doing Phase 2 of our solar; doing batteries later this year so split the full project into 2 parts so that they could be both be counted in the tax credit for 2018/2019. Currently have a SE10000H, the first one installed in Ohio last year I believe. Total of 13.3kw of panels going to it and it's been great for almost a year. We have 3 strings; 16, 10, and 10 of 370 XL panels. The plan moving forward is to add a SE7600H and place the 2 south-facing 10 panel strings on it, then add 12 more panels in a string of their own to enable the SE10000H to have 1 string of 16 west facing panels and 1 string of 12-13 east facing panels. On paper, according to the location and angles of everything, this maximizes the output and keeps us from clipping, while also allowing us to use as much roof-space as possible.
Now, onto the questions. Our AHJ is using NEC 2014, and I've been pouring over the 705.12 section. The SE10000H has a 42.5 amp output rating and we have 200amp service so code dictated we do a supply side connection for backfeed. My electrician chose piercing lugs on the main lines above the main breaker. This was approved by the AHJ and seems to have worked well. Now that we are adding a second inverter, I had planned, unless corrected on here, to do a 100amp sub panel with 100amp main breaker going into the supply side tap with larger 2-2-2-4 wire (I have parallel taps ready to install, and would like to hear opinions on that too). Then the SE7600H would have a 40 amp breaker on that panel and the SE10000H would have a 60amp breaker on that panel. My understanding is that the breakers are not exceeding the ampacity of the busbar (100amps) and since the 100amp breaker is not an OCPD, just a disconnect, the 120% rule does not apply here. I currently have an exterior fused disconnect that the inverter output goes through before going into the main panel. That is also being upgraded from 60 amps to 100amps.
Apologies for using the term sub-panel, from my research, it should be considered an "AC combiner" box or something similar.
So my questions are, am I interpreting all this correctly and does the plan seem standard for this type of setup? I posted over on Reddit and butchdeal was very helpful. He seemed to think that this was the way to go from the solar perspective And it seems like this forum also has a wealth of electrical knowledge as it pertains to NEC/solar. Information from forums would be super helpful so I can have a meaningful discussion with my AHJ on this. Solar is popular in my area, but not sure dual-inverters are something they haven't seen on residential yet.
Thanks in advance.
We are doing Phase 2 of our solar; doing batteries later this year so split the full project into 2 parts so that they could be both be counted in the tax credit for 2018/2019. Currently have a SE10000H, the first one installed in Ohio last year I believe. Total of 13.3kw of panels going to it and it's been great for almost a year. We have 3 strings; 16, 10, and 10 of 370 XL panels. The plan moving forward is to add a SE7600H and place the 2 south-facing 10 panel strings on it, then add 12 more panels in a string of their own to enable the SE10000H to have 1 string of 16 west facing panels and 1 string of 12-13 east facing panels. On paper, according to the location and angles of everything, this maximizes the output and keeps us from clipping, while also allowing us to use as much roof-space as possible.
Now, onto the questions. Our AHJ is using NEC 2014, and I've been pouring over the 705.12 section. The SE10000H has a 42.5 amp output rating and we have 200amp service so code dictated we do a supply side connection for backfeed. My electrician chose piercing lugs on the main lines above the main breaker. This was approved by the AHJ and seems to have worked well. Now that we are adding a second inverter, I had planned, unless corrected on here, to do a 100amp sub panel with 100amp main breaker going into the supply side tap with larger 2-2-2-4 wire (I have parallel taps ready to install, and would like to hear opinions on that too). Then the SE7600H would have a 40 amp breaker on that panel and the SE10000H would have a 60amp breaker on that panel. My understanding is that the breakers are not exceeding the ampacity of the busbar (100amps) and since the 100amp breaker is not an OCPD, just a disconnect, the 120% rule does not apply here. I currently have an exterior fused disconnect that the inverter output goes through before going into the main panel. That is also being upgraded from 60 amps to 100amps.
Apologies for using the term sub-panel, from my research, it should be considered an "AC combiner" box or something similar.
So my questions are, am I interpreting all this correctly and does the plan seem standard for this type of setup? I posted over on Reddit and butchdeal was very helpful. He seemed to think that this was the way to go from the solar perspective And it seems like this forum also has a wealth of electrical knowledge as it pertains to NEC/solar. Information from forums would be super helpful so I can have a meaningful discussion with my AHJ on this. Solar is popular in my area, but not sure dual-inverters are something they haven't seen on residential yet.
Thanks in advance.