The Siemens SENTRON 3VA1120-3EF32-0HC0 is a 3-pole molded case circuit breaker rated 20 A continuous at 40 °C ambient, with no derating needed up to 55 °C — it holds 20 A through that band, then steps to 19 A at 60 °C and 70 °C. The interrupting ratings step with system voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. For a 480 V distribution panel, the 32 kA at 440 V is the closest published point — the 11.9 kA at 500 V is conservative for 480 V systems. This is a line-protection design, not a motor-protection or generator-protection variant — the thermal-magnetic trip curve is set for feeder and distribution duty.
In a standard 600 mm deep enclosure, you have clearance for wiring gutters and the shunt trip leads. The 76.2 mm width (3 inches) is a standard 3-pole MCCB footprint; it occupies one 3-pole position on a DIN rail or panel-mount base.
Maximum power loss is 12 W at rated current. In a densely packed panel, that 12 W per breaker adds up — if you have ten of these in a row, you're looking at 120 W of heat to evacuate. The storage minimum is the handling limit, not the running limit.