The Siemens SENTRON 3VA1120-6EF36-0KC0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection, rated 20 A at 40 °C and carrying a 220 kA breaking capacity at 240 V AC — enough to handle high-fault utility feeds or transformer secondaries without cascading upstream.
The 20 A continuous rating holds flat from 40 °C up to 55 °C, then derates to 19 A at 60–70 °C — so in a warm panel (say 50 °C ambient) you still get the full 20 A; only above 55 °C do you lose 1 A. Breaking capacity steps down with voltage: 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500/690 V.
The 3-pole MCCB measures 76.2 mm wide, 130 mm tall, and 70 mm deep. Maximum power dissipation is 12 W — negligible for panel thermal budgeting, but worth noting if you pack multiple breakers in a sealed, non-ventilated enclosure.