DIY System in VA Beach

[disposaleer]

Hey everyone, I've done my best to sort through the information here and on Mike Holt's forums, and this is what I came up with. Does anyone care to sanity check my plan before I start drilling holes?

I've got 21 280w SolarWorld panels with Enphase m215 w/IG micro inverters split into strings of 10 and 11. I figure these will run at 9 and 9.9 amps respectively. I've got the Enphase trunk cable running through a Soladeck roof penetration probably to a j-box just inside the attic to make the transition to 12/3 NM (to get around any possible NM on the roof concerns). These two circuits run for about 75' to two 20amp breakers in a 100amp load center. These combine there then go to a 60amp AC disco, to the solar generation meter, then to a 30amp breaker in the 150amp main panel.

Other than the 20amp breakers, the load center, and the disco being oversized, does anyone see any glaring mistakes here? I am using the circuits as the EGC for the racking through the micro inverters IG, and didn't see any specific size requirement for it. In the future I might tie the top right 4 panels into the string with 10 and add more panels on the garage into the string that would be left with 7 panels on it, but that would require me to upgrade my main panel. The new 14 panel string would be at 12.6 amps which still works with 12/3 right?

I also know the 280w panels lie outside the recommended spec of the m215's, but my house faces more west than south, and I figure after first year degradation....maybe I'm just being cheap.

Thanks in advance.

[ButchDeal]

I also know the 280w panels lie outside the recommended spec of the m215's, but my house faces more west than south, and I figure after first year degradation....maybe I'm just being cheap.
Thanks in advance.

The azimuth doesn't make any difference for your inverter sizing. It means less production due to less time in the sun but the sun still sets in the west so in the evening it will still hit peak power.

If you were being cheap you would get 260W modules.
If you haven't already purchased inverters, I would recomend either going with M250s or even better and most likely cheaper, go with SolarEdge. You could put in an SE6000 and have lots of room for expansion or if you can swing a 40a breaker you could go with the SE7600 and have powerwall capabilities.

[disposaleer]

Thanks ButchDeal, that makes sense. I'm basically putting a cap on my production by using the M215s instead of the M250s or a larger string inverter.

I don't think I can swing a 40a breaker unless I can reduce my main breaker down from a 150a. I haven't looked close enough at my main to see if the breaker is replaceable. I think I've seen something about de-rating main breakers on some of the forums, but I'm not sure if that applies here and I am almost certain that is beyond my abilities.

Any other glaring issues jump out at you?

[ButchDeal]

Thanks ButchDeal, that makes sense. I'm basically putting a cap on my production by using the M215s instead of the M250s or a larger string inverter.

I don't think I can swing a 40a breaker unless I can reduce my main breaker down from a 150a. I haven't looked close enough at my main to see if the breaker is replaceable. I think I've seen something about de-rating main breakers on some of the forums, but I'm not sure if that applies here and I am almost certain that is beyond my abilities.

Any other glaring issues jump out at you?

So then put in a SolarEdge SE5000 with the same 30a breaker and have more inverter capacity, no need for AC combiner, cheaper & simpler wiring.

Yes if you derate the main breaker you could fit the larger feed in. or do a line side tap (take an electrician).