The Siemens SENTRON 3VA1120-3ED36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 20 A continuous at 40 °C, using a TM210 thermal-magnetic trip unit. The 75.6 kA breaking capacity at 240 V tells you it can safely interrupt a fault of that magnitude without the arc flashing over; at 415 V that figure drops to 52.5 kA, and at 690 V it holds at 11.9 kA.
Ratings that matter for the panel
Thermal rating holds at 20 A all the way to 55 °C; at 60 °C it derates to 19 A and stays there through 70 °C. That's a flat curve — you don't lose headroom until the panel gets genuinely hot. The TM210 trip unit is fixed thermal and magnetic — no interchangeable rating plugs, no electronic adjustments. That keeps it simple and reliable for a distribution feeder where you set it once and forget it. Power loss is 12 W maximum, which matters for thermal calculations in a crowded enclosure.