Does the 12000XP have 120V Operation mode like the 6000XP does? There's nothing in the 12000XP manual, but I'm wondering since it's so similar to the 6000XP, if it works the same?
For reference, the 120V Operation was added to the 6000XP in a firmware update and added to the 6000XP manual in version 1.6.4.
This is the mode where the 6000XP operates at reduced capacity, only supporting 120V output. Where you only connect L1 (black) and N (neutral) but do not connect a L2 for either grid or load.