the point of grid interconnection
There was a change in the 2008 NEC that allows the sum of the supply breakers to be 120% of the busbar ratings for both commercial and residential solar pv installations. This change in the NEC rules allows small solar pv systems to be interconnected without having to upgrade the service panel. Grid interconnection is quite complex, it’s not as easy as simply wiring your grid tie inverter into the service panel.
This information is good to know weather your the person conducting the installation or intend to hire a professional to grid tie your solar electric system, you must make sure your installation is up to NEC standards.