The neutral for the 2 120A legs can be overloaded with 58A (for a 7kW gen) before the CB will trip. Fact is the neutral current is the sum for 2 120V circuits and not the difference like a 120/240V circuit. This is also not the same as a 50/30 adapter where both the 30A hot and neutral are protected by a 30A CB.
Therefore its not safe unless the neutral is wired to handle 58A. Will it appear to be OK? Sure especially if you're not near maximum load. Otherwise the wire can overheat unless upgraded. Plus the voltage drop for 58A is higher.
