Under the busbar interconnection rule, the sum of the main utility overcurrent device plus the inverter (power-production) overcurrent device generally may not exceed what percent of the busbar rating?

Explanation

Section 705.12(B)(3) allows the sum of the ampere ratings of the main supply overcurrent device and the power-production (inverter) overcurrent device to be up to 120 percent of the busbar rating when the inverter breaker is at the opposite end from the main. Exceeding 120 percent would risk overloading the busbar.