The Siemens 3VA1220-4EF32-0AC0 is a 3-pole SENTRON molded case circuit breaker (MCCB) with a TM240 thermal-magnetic release, rated 200 A continuously at 40 °C. At 240 V it interrupts 121 kA symmetrical, enough to handle most secondary-side transformer faults or high-fault panel feeds without cascading upstream.
Rated current across the temperature range
This breaker holds its full 200 A rating from 40 °C through 50 °C, then derates linearly: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, and 176 A at 70 °C. The thermal-magnetic release responds to ambient heat; packing multiple breakers in a small enclosure without de-rating is a common miss that causes nuisance tripping on warm days.
Breaking capacity by voltage level
The interrupting ratings step down with system voltage: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, 17 kA at 500 V, and 11.9 kA at 690 V. For a 480 V panel in North America you'd use the 440 V figure (52.5 kA) as the conservative benchmark — that's the closest standard voltage below 480 V. That 52.5 kA SCCR headroom covers most industrial distribution boards; only high-fault petrochemical or data-centre feeds would need a higher-rated frame.
Physical fit and auxiliary switch
Dimensions: 105 mm wide, 158 mm high, 70 mm deep — a standard 3-pole MCCB footprint for Siemens SENTRON 3VA frames. The supplied basic switch code is 3VA12204EF320AA0, which is the internal switching mechanism; you order the full assembly as the 3VA1220-4EF32-0AC0.