Article 960

[QAbyJMB]

when sizing the proper rating for a panel-board, considering the rating of the utility side power and solar power side sources, how does the percentage factor apply (should you total both the utility side and the solar power side ratings)?

 

[jaggedben]

Total both the utility and the solar and divide by 1.2. Use a panelboard rated higher than that number.

It's article 690 (not 960). In the 2011 NEC it's article 705.

 

[ggunn]

when sizing the proper rating for a panel-board, considering the rating of the utility side power and solar power side sources, how does the percentage factor apply (should you total both the utility side and the solar power side ratings)?

Yes. The main breaker rating plus that of the breaker being backfed by the PV inverter cannot exceed 120% of the rating of the panel busbar.