Breaking capacity is 75.6 kA at 240 V AC and 52.5 kA at 415 V AC — that's the fault current it can safely interrupt without welding contacts or venting plasma.
Rated current holds at 40 A from 40 °C up to 50 °C, then drops to 39 A at 55 °C and 60 °C, 38 A at 65 °C, and 37 A at 70 °C. That's a shallow derate curve — you lose only 3 A across a 30 °C rise, so it's stable in a warm panel. Maximum power loss is 7.2 W — that's the heat it dumps into the enclosure at full load. In a dense panel, that matters for thermal coordination; you don't want to stack a row of these without some ventilation.