What this 250 A 4-pole MCCB carries
The Siemens SENTRON 3VA1225-5GF42-0AE0 is a 4-pole molded case circuit breaker rated 250 A continuous at 40 °C, with a TM240 thermal-magnetic release sized for line-protection duty. It sits in the 3VA1 frame family and is listed as current-production (active lifecycle stage). The interrupting ratings climb with system voltage: 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. That SCCR curve means the breaker handles high fault currents on low-voltage distribution and still clears a solid fault on a 690 V drive bus — useful for mixed-voltage panels where the same frame feeds both 480 V and 600 V sections. Rated insulation voltage is 800 V, so the 690 V interrupting rating is within the design envelope — not a derated edge case.
Thermal derating and panel integration
At 40 °C the breaker carries a full 250 A. Derating starts at 55 °C (243 A), dropping to 230 A at 65 °C and 223 A at 70 °C. In a sealed enclosure with multiple breakers ganged, that 70 °C figure governs the real-world ampacity — don't load it to 250 A if the ambient inside the panel hits 60 °C. Physical dimensions: 158 mm tall, 140 mm wide, 70 mm deep. Maximum power loss is 57 W at rated load.
Lifecycle and compliance posture
Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. The storage minimum matters for unheated warehouses in cold climates — the breaker can sit at -40 °C without damage, but don't energize it below -25 °C.