The Siemens SENTRON 3VA1020-4ED36-0JC0 is a 3-pole molded case circuit breaker rated 20 A continuous, with a TM210 thermal-magnetic overcurrent release. The interrupting ratings are the headline here: 121 kA at 240 V AC, 75.6 kA at 415 V, and 52.5 kA at 440 V — that's high-fault-capacity for a 20 A frame, so it can sit upstream of a panel with a high available fault current without needing a current-limiting fuse ahead of it. The 800 V rated insulation voltage (Ui) means it's comfortable on 480 V or 600 V class systems, not just 240 V.
Ratings and what they mean for fit
Rated current holds at 20 A from 40 °C through 55 °C ambient, then derates to 19 A at 60 °C through 70 °C. That flat plateau means you don't lose headroom in a warm enclosure until past 55 °C — useful for a panel sitting near a motor or in a non-conditioned electrical room. The TM210 release is a fixed thermal-magnetic type; no interchangeable trip units, so the 20 A rating is baked in. The 2 auxiliary switches (HQ type) give you two sets of form-C contacts for status feedback to a PLC or alarm annunciator — no separate aux switch kit to order.
Panel fit and integration
Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. That's a compact footprint for a 3-pole MCCB with 121 kA interrupting capacity — it fits in a standard distribution panel without eating up multiple pole spaces. The 3VA family uses a common mounting pattern, so if you're swapping from an older 3VA1 frame, the footprint matches. Power loss is 12 W maximum at rated load, which is modest for the interrupting rating; keep that in mind for thermal calculations in a sealed enclosure.