Rated at 20 A continuous at 40 °C, it holds that rating flat through 55 °C, then derates to 19 A from 60 °C up to 70 °C ambient. That matters if you're stuffing it into a hot corner of a panel next to a drive or transformer — you don't lose headroom until the box hits 60 °C. The interrupting ratings climb steeply with lower voltage: 187 kA at 240 V, 121 kA at 415 V, 76 kA at 440 V, and 17 kA at 500 V. For a 20 A frame that's serious fault-clearing ability — it can break a 187 kA bolted fault on a 240 V service without welding its contacts shut.
Sizing and selectivity in the panel
The maximum rating across the frame is 320 A — that's the bus stack limit, not the trip unit. The TM210 release limits this specific variant to 20 A continuous. If you need a higher amp rating in the same physical footprint, you'd step to a different TM release (e.g., TM320 or TM630) on the same 3VM1 frame.
Front face carries IP40 protection — splash-resistant from the front but not sealed against hose-down. That covers most industrial control rooms and outdoor cabinets in temperate climates, though sustained operation above 70 °C is out of spec.