250 A SENTRON MCCB with undervoltage release
The Siemens SENTRON 3VA1225-5GF42-0BA0 is a 4-pole molded case circuit breaker rated at 250 A continuous, built for line protection in distribution panels. It carries a TM240 thermal-magnetic release — thermal for overload, magnetic for short-circuit — and ships with an integrated undervoltage release (UVR) that trips the breaker when control voltage drops below the dropout threshold. Breaking capacity runs from 187 kA at 240 V down to 17 kA at 690 V, so it handles high-fault utility feeds at the lower voltages typical of North American 240/277 V split-phase or 480 V distribution, and still clears a 17 kA fault on a 690 V industrial bus. The 800 V rated insulation voltage gives headroom for 690 V systems without derating the dielectric. Current rating holds flat at 250 A up to 50 °C ambient — no derating needed in a typical 40 °C panel. Above that the curve drops to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If the enclosure runs hot from other devices, factor that derating into the load schedule.
Panel fit and integration
The 3VA1225-5GF42-0BA0 measures 140 mm wide by 158 mm tall by 70 mm deep — a standard 4-pole MCCB footprint for DIN-rail or rear-panel mounting in a SENTRON distribution board. The 59.5 W maximum power loss means the enclosure needs some ventilation or forced air if the breaker is continuously loaded near 250 A alongside other high-current devices. Operating temperature range is -25 °C to 70 °C; storage range -40 °C to 80 °C. The undervoltage release is factory-integrated — no separate auxiliary module to mount and wire, saving a DIN position.