That 250 A holds flat from 40 °C through 50 °C, then derates to 243.3 A at 55 °C and 223 A at 70 °C — so in a warm enclosure you lose about 11% of headroom by the time you hit 70 °C ambient. The interrupting ratings are what drive the bus bracing decision: 187 kA at 240 V, 121 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V.
Sizing and selectivity — the TM240 release and N-conductor protection
The N-conductor protection is set at 50 % of the phase rating, which is typical for 4-pole breakers feeding loads where the neutral is sized at half the phase conductors — common in North American 277/480 V Y panels.
Panel fit and physical integration
Front protection is IP40, so it is dust-protected on the face but not sealed against hose-down; keep it inside a cabinet rated for the environment.
What the interrupting ratings mean for your fault-current study
At 415 V the 121 kA still exceeds what most 2 MVA substations can push into a bolted fault.