What this MCCB is and what it does
The Siemens SENTRON 3VA1020-4ED32-0KC0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection — meaning it sits at the feeder or branch circuit to guard against overloads and short circuits, not motor or generator protection. It carries a rated current of 20 A across the 40 °C to 55 °C band, derating to 19 A at 60 °C through 70 °C. The breaking capacity is the headline: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 121 kA figure at 240 V tells you this breaker can interrupt a fault current up to that level without failing — critical for high-fault panels near large transformers or upstream of multiple drives.
What the ratings mean for your panel
Rated insulation voltage is 800 V, so the breaker is rated for use in 690 V systems with margin. The 3-pole design fits standard 3-phase feeders. Power loss is 12 W maximum — that's the heat it dumps into the enclosure at full rated current; factor it into your thermal budget if you're stacking multiple breakers in a sealed panel. The auxiliary switch configuration is 2 HQ switches, and the auxiliary release is a shunt trip (STL) — that shunt trip lets you remotely trip the breaker via a control signal, which is useful for emergency-stop circuits or interlocking with a fire alarm system. No undervoltage release, no ground-fault monitoring, no communication function on this variant. It's a straightforward line-protection MCCB with a shunt trip for remote trip capability.
Physical fit and panel integration
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — that's a standard SENTRON 3VA form factor. It mounts on a DIN rail or can be screw-mounted to a backplate. The 70 mm depth is shallow enough for most 200 mm deep enclosures; check your door clearance if you have a rotary handle mechanism. The width of 76.2 mm (3 inches) is a 3-pole footprint; a 4-pole version would be wider. The shunt trip wiring needs a separate control circuit — factor that into your panel layout.