MCCB for feeder protection — 250 A frame with high interrupting capacity
The Siemens 3VA1225-4EF32-0KH0 is a SENTRON molded case circuit breaker (MCCB) rated 250 A continuous at 40 °C through 50 °C, 3-pole, designed for line protection in distribution panels. Its interrupting capacity reaches 121 kA at 240 V AC, 75.6 kA at 415 V AC, and 52.5 kA at 440 V AC — figures that place it in the high-fault-current tier, suited for main or large-feeder positions where available fault current exceeds standard MCCB ratings. Thermal derating is gradual above 50 °C: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. Rated insulation voltage is 800 V, supporting 690 V AC systems with margin. Dimensions are 158 mm high, 105 mm wide, 70 mm deep — a 3-pole frame that fits standard Siemens 3VA switchboard and enclosure cutouts.
Auxiliaries and releases — shunt trip plus two auxiliary switches and a trip alarm
This variant ships with a shunt trip release (STL) for remote tripping, plus two auxiliary switches and one trip alarm switch (HQ configuration). The auxiliary switches signal breaker position; the trip alarm indicates a fault trip independent of handle position. No undervoltage release or ground-fault monitoring module is fitted — those are add-on options in the 3VA platform. Power loss at rated current is 57 W maximum — relevant for enclosure thermal calculations in sealed or high-ambient panels. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.