Siemens SENTRON 3VA1225-6EF32-0AJ0 — 250 A MCCB, Line Protection, TM240 Release
The Siemens 3VA1225-6EF32-0AJ0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a 250 A continuous rating at 40 °C through a 3-pole construction with a TM240 thermal-magnetic overcurrent release. The interrupting ratings span the voltage range: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. These SCCR values mean the breaker can safely clear fault currents up to those levels without upstream cascade — critical for selectivity studies on a 415 V or 690 V industrial feeder. Rated insulation voltage is 800 V, and the breaker dissipates 57 W maximum at full load. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Thermal Derating and Physical Fit
The 250 A rating holds flat from 40 °C through 50 °C, then derates to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If the panel ambient runs above 50 °C, the continuous current must be adjusted per this curve — a common oversight when the breaker is mounted near other heat sources in a sealed enclosure. Dimensions are 70 mm depth, 105 mm width, 158 mm height. The 105 mm width is standard for a 3-pole MCCB in this frame size, meaning it fits existing SENTRON mounting footprints and busbar systems without panel rework.
Auxiliary Switching and Indication
The breaker ships with 2 auxiliary switches plus 1 trip alarm switch (HP type). The trip alarm provides a separate signal path that closes only on a fault trip — useful for remote annunciation or PLC input that distinguishes a manual open from an overcurrent event. A mechanical trip indicator is also present on the front face. The supplied basic switch assembly carries order code 3VA12256EF320AA0. No undervoltage release, no ground-fault monitoring, and no communication function are fitted on this variant.