Just going to drop this tidbit here from the spec sheet located
here which is about the
120 amp Breaker and is also in the PNG
Based on their tolerances the breaker should be able to run at 240amps for 10-40 seconds without tripping or 160 amps for somewhere around a minute of time.
The
40 amp snap actions are much more prone to tripping, as low as 6 seconds at 135% current as seen
here (Snap action breakers)