Start with the load.
In your example, you state a load of 290A. Therefore, your wire - after taking into account all derating factors (temperature, number of conductors in the raceway, etc.) must calculate out to at least 290A. Keep in mind that different types of loads, such as welders, have specific factors you need to consider. In the end, this is a MINIMUM wire size. There is no issue with using a larger wire.
Likewise, your fuse or breaker is selected based upon both your specific application, and your load. It also needs to be at least 290A. As before, different types of loads will have specific ways to calculate the breaker to use.
Unlike with the wire, the breaker or fuse you calculate is the MAXIMUM size breaker or fuse. You can always go smaller.
For situations where the circuit is designed for a specific load, there is no code issue with the wire rating being less than the rating of the fuse or breaker. We put 40-amp breakers on #12 (25-amp) wire all the time, when we're powering air conditioners.
At the other extreme, there's no code rule against protecting a 500MCM wire with a 10-amp fuse.
We tend to get confused on this point simply because we usually think in terms of 'convenience receptacle' circuits, which are sized in a unique manner.