I missed reading your post Windy One, which you also misinterpreted. I have a 240V/30A breaker which is good for 7200 Watts, using 10/3 wire (2 - 120V/30A leads).
Anyways, I just finished installing the panels and wiring everything up. I ended up doing something a bit different. I have three buildings on my property; our main house, a carriage house/garage, and another outbuilding.
- I installed 14-300W panels and 7-600W inverters on the main house. I ran 2 dedicated 12 gauge cables on 20A/120V breakers. One line has 4 inverters plugged in, and the other has 3. The capacity of each line/breaker is 2400W so it matches the maximum rated output of the 4 inverter set of panels/inverters. In reality the maximum output of each panel set/inverter is quite a bit less than 600W. The most I've measured is ~500W at noon on a cloudless day.
-On the outbuilding I installed 4-300W panels with 2-600W inverters and tied it into a 120V/20 amp (1800Watt) dedicated circuit.
- The carriage house/garage has the 10 gauge wiring/circuitry I noted above. I haven't installed panels yet on this building because of access issues. The roof has a steep pitch and is quite high off the ground so I need to set up scaffolding when I eventually add panels to this building. At some point I'll add another 16-300W panels to this building, as that's how many I can easily fit.
Interestingly, I measured the output of a very slightly dust-covered panel, then immediately cleaned the panel with water and a scrubber. I squeegee'd the excess water off and re-measured the output. It gained over 10% output! So keep those panels clean!