Always use stranded wire for mobile use to prevent stress cracking from vibration. good advice above on diference between 120 and 12 volt electrical devices. You should be able to go online and find an installation manual and wiring diagram for your inverter. for the output 12 gauge wire would be fine for a 20 amp receptacle, 14 gauge for 15 amp receptacle. also make sure the wire is approved for exposed use if not in conduit or behind protective coverings. Some inverters have output protection built in, some of the larger ones have output protection for the unit, but it is to big for the individual circuits, also make sure to properly size the input wires, 2000 watts output at 120 volts is 16.7 amps, however the input at 12 volts is 166.7 amps. size of wire is very dependent on distance from battery to inverter, a 3 foot run of cable with a 2k inverter would work on #2 wire but the volt drop would be on the high end, I would go with 2/0 cable which will result in a 1% loss at full load. There are charts on line that will let you know what wire size to use based on distance and load. Make sure to use good quality full copper wire not copper clad aluminum with lugs pre pressed on, if pressing your own lugs make sure to use a good brand such as Ancor, not the cheap ones from Amazon as they will not take or keep a proper crimp and loose crimps cause heat and worse issues. also use a good quality fuse and holder or circuit breaker on the input side near the battery, Bussman or similar, had a knockoff from Amazon fail on my Jeep within 2 months, never again.
