Which factor primarily impacts the maximum quantity of microinverters per AC branch circuit?

• A. Light intensity and temperature averages at the installation site
• B. Conductor size (12 AWG) enclosed in the Q cable
• C. Microinverter DC input from solar panels
• D. Microinverter AC voltage and grid frequency

Answer: (B)

The limiting factor is the current-carrying capacity of the AC wiring. The Q cable uses 12 AWG conductors, and those conductors have a specific ampacity—the maximum current they can safely carry with the protective device in place. Each microinverter on the branch adds AC current to the circuit, so the total current from all installed units must stay below that ampacity. Once you reach that limit, you can’t legally add more microinverters to the same branch without upgrading the conductor size or protection. Light intensity and temperature affect how much DC power the panels produce, not how much current the AC branch can carry. The DC input of the microinverters and the fixed AC voltage/grid frequency don’t determine how many units can be on one branch—the conductor size does.