Very Nice Setup, they did not make the 325watt panels when I did mine, I am a little jealous. In a good way, that rocks what you got going there though. As for the 8awg between the solar panel and main power panel, that is fine, I meant the line coming from your roof for each solar array string. My electrician tried using 12awg and told me 14awg was perfectly fine, I said no I want 10awg and I will be for the extra costs. Sure going from 12 to 10 only saved about 2-3% losses, but to me it was worth it, 14awg was out of the question.
Also for each array, per enphase recommendation, you should center tap the array, tapping it at the end of a 11 panel run will cause losses, but if you tap in the middle, then you minimize those losses on the enphase cable. Probably pretty minimal, but still it does matter if you are looking for near zero losses.
So the next gauge wire that has the most importance because it is usually the longest run is the wire going from each solar array string, down to the Joiner… My local codes required me to have a whole separate breaker box, to join the strings, as well as an single external solar panel kill switch. 8awg was great for your joiner to your mains, I see no losses there, besides it is such a short run. Oh by the way my local code also required yet another breaker fuse to go into the mains. They were way over kill, so I have to send each string through 3 breakers and a big kill switch, all generating losses. each array has a breaker, then one big kill switch outside house with the joined strings, then one breaker after string joins into main panel, then of course the whole house main 100amp breaker. I am pleased to see they let you just tap the mains, that makes so much more sense with an enphase system.
You can go online and bring up a calculator for wire losses, that is how I decided on 10awg for each string.
So three questions…
- Is your 3 solar array strings center tapped (if not there will be losses from the voltage rise there)
- what gauge wire from each solar array to your joiner?
- what is the length of the run from your solar array to your joiner?
The length of the run will most likely be more than you think, because it is mostly likely weaving down walls and around bends, but it all depends on your setup, it might be a really short run, mine are about 50feet.