MCCB for line protection — 250 A frame, 3-pole, TM240 release
The Siemens SENTRON 3VA1225-6EF32-0CA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, with a TM240 thermal-magnetic overcurrent release. Its continuous current rating holds 250 A from 40 °C up to 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 — so in a warm panel you lose about 5% per 5 °C above 50 °C. The insulation voltage is rated 800 V, and the unit includes an undervoltage release (UVR) as the auxiliary release type.
Breaking capacity — what the ratings mean for selectivity
Breaking capacity varies sharply with system voltage: 220 kA at 240 V AC, 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. At 415 V, 154 kA is well above typical utility fault levels in most industrial installations, giving headroom for selective coordination with downstream breakers. At 690 V the 17 kA figure still covers most motor-drive branch circuits, but verify available fault current if feeding a large transformer.
Integration — panel fit and wiring
Dimensions: 105 mm wide, 158 mm high, 70 mm deep. The 105 mm width is standard for a 3-pole MCCB in this frame size — fits a typical 4-module (4 x 27 mm) DIN-rail footprint or direct screw-mount panel cutout. The undervoltage release (UVR) is wired separately; verify coil voltage against the control circuit before energizing. Operating temperature range -25 °C to +70 °C, storage -40 °C to +80 °C.