The Siemens SENTRON 3VA1120-3ED22-0AA0 is a 2-pole molded case circuit breaker rated for line protection, carrying 20 A continuously from 40 °C up to 55 °C without derating — at 60 °C it still holds 19 A, so in a warm enclosure you keep nearly full ampacity. The interrupting capacity is the headline: 75.6 kA at 240 V AC and 52.5 kA at 415 V AC, which means it can clear a fault upstream of a distribution panel without needing a current-limiting fuse ahead of it. That kind of SCCR headroom simplifies coordination studies for the site electrical engineer.
Thermal-magnetic release and footprint
That keeps the BOM simple but means you size the breaker to the load, not the other way around. The 50.8 mm width and 70 mm depth let it snap onto a standard DIN rail in a panel that's already tight on fill factor; the 130 mm height clears most gland-plate layouts.