What it is and what it does
The Siemens 3VA1220-5GF42-0BA0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection — meaning it sits at the panel main or a large feeder, not a motor branch. It carries a continuous 200 A at 40 °C through all four poles. The TM240 thermal-magnetic release handles overload and short-circuit trip coordination; the undervoltage release (UVR) lets a safety circuit or E-stop drop the breaker without a manual trip.
Breaking capacity — what the numbers mean for your fault level
This breaker interrupts 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V (–). Those are the maximum fault currents it can clear without welding or rupturing. For a 480 V panel in North America, the 75.6 kA at 440 V is the closest published figure — expect similar capability at 480 V, but the 415 V rating (121 kA) is the one to use for IEC 60947-2 verification in a 400 V system.
Thermal derating — it stays at 200 A until 50 °C
The 200 A rating holds flat from 40 °C through 50 °C (–). Above that it derates: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, 176 A at 70 °C (–). If your panel ambient hits 60 °C, you lose 12 A — plan the load accordingly. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Panel fit — dimensions and mounting
The breaker measures 140 mm wide, 158 mm high, 70 mm deep. It is a 4-pole unit with no communication function and no ground-fault monitoring. The undervoltage release is factory-fitted; no voltage-trigger accessory is included. Power loss at full load is 44.5 W — factor that into enclosure thermal calculations.