Siemens SENTRON 3VA1120-6EF32-0BC0 — 20 A MCCB with 220 kA interrupting capacity
The Siemens SENTRON 3VA1120-6EF32-0BC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 20 A at 40 °C and a massive 220 kA breaking capacity at 240 V — that SCCR headroom means it can sit at the service entrance or on a high-fault panel feeder without cascading upstream. Rated insulation voltage is 800 V, and the interrupting ratings scale down with voltage: 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V — so it stays effective on 480 V or 600 V class systems where fault current can still hit tens of kiloamps.
Current rating holds flat at 20 A from 40 °C up to 55 °C, then derates to 19 A at 60 °C through 70 °C — so in a warm enclosure near the top of the ambient range you lose only 1 A, not a full frame size. Dimensions are 76.2 mm wide (3 in), 130 mm tall (5.12 in), and 70 mm deep (2.76 in) — a standard 3-pole MCCB footprint that fits a DIN-rail or panel-mount backplate without surprises. Maximum power loss is 14.5 W — modest enough that ventilation slots in a typical steel enclosure handle the heat without forced air, but worth checking if the breaker is packed next to other high-dissipation gear.