The breaking capacity tells you where this breaker can safely interrupt a fault: 220 kA at 240 VAC, 154 kA at 415 VAC, 121 kA at 440 VAC, and 17 kA at 500 V or 690 VAC. At 690 V the 17 kA is still respectable for industrial loads at that voltage level. The TM240 release provides thermal-magnetic protection: the thermal element handles sustained overloads, the magnetic element clears short-circuits fast.
Current derating — the real-world rating
Above that it derates: 39 A at 55 °C and 60 °C, 38 A at 65 °C, 37 A at 70 °C. The 10.8 W maximum power loss also contributes to internal heat rise; allow ventilation or spacing in dense DIN-rail layouts. Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — standard 3-pole MCCB footprint that clips onto DIN rail or mounts via the rear panel.