I have 800 amp main service 240/120 delta high leg. I plan on doing a load side tape to a 200 amp fused disconnect. To a 68kva step up transformer 240v primary delta, secondary 480 volt secondary to a 150amp 480v solar sub panel with a 100 amp back feed breaker, feeding Solar edge 66.6kus 480 inverter. Continues out put is 80 amps x1.25 = 100. My Question is where does the 120 percent start and end. Does the first 200 amp fused disconnect have to be within the 120 percent of 800 amps is 960 amps= 160 backfeed space thanks