Connect solar combiner to sub panel | Information by Electrical
The code says that the sum of the ratings of the OCPDs that suppy the panel cannot exceed 120% of the panel rating. The breaker on the line side of the panel feeder and the solar inverter breaker both feed the panel. If the panel is rated at 100 amps and is fed by a 100 amp ocpd, the maximum rating of the solar inverter breaker would be 20 amps.