4 AWG is good for 85 amps (depends on the tables, that might be in conduit). The fuse, not the wiring, should be the weakest link.I am based on the diagram. Should it be less? The other connection points are all 80amp
...and the diagram you linked to calls for 4/0 AWG, which is entirely different than straight 4.
4/0 has around 5x the cross-section of copper. It's HUGE wire.