It was suggested to use a 210 amp fuse. These are not easily available, I suggested the next higher value that is available.
A 2000 watt inverter at full power will take 170 amps plus extra current to cover power loss from cable loss and inverter efficiency, say 20 amps. Its normal to allow overhead on the fuse rating which gets into the 225 to 250 range.
Many inverters have an overload rating up to twice the continuous rating, some allow this excess for several seconds or longer to allow starting of loads like motors. If the inverter were to be used in such an application the fuse and perhaps cables would need up rating to allow for the higher current.
Its good engineering practice and even the law in many situations, that states cables and systems need over current protection at or very near the power source.
I still dont understand the comment 'what is it based on'.
Mike