It's configured for line protection — the primary role is protecting cables and distribution buswork from overloads and short circuits, not motor or generator protection. The interrupting ratings are 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V, which means it can safely clear fault currents up to those levels at the respective system voltages without rupturing or welding contacts. The 100 A rating holds flat from 40 °C through 50 °C ambient; above that it derates to 96 A at 55 °C, 94 A at 60 °C, 92 A at 65 °C, and 90 A at 70 °C — the derating curve matters if this breaker lives in a crowded enclosure with other heat sources.
That 76.2 mm width on a 3-pole frame is a standard 3-module footprint for SENTRON 3VA breakers — it clips onto the mounting plate or DIN rail adapter without eating extra width.