What it is and what it does
The Siemens SENTRON 3VA1225-6EF32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current, designed for line protection in distribution panels and industrial switchgear. Its TM240 thermal-magnetic overcurrent release provides fixed thermal and magnetic trip settings — no adjustment needed, which simplifies specification and reduces setup time on the line. Breaking capacity is the headline: 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. That 220 kA at 240 V means it can safely interrupt a fault current up to 220,000 A at that voltage — critical for high-fault locations like transformer secondaries or large motor control centers where available fault current is high. At 690 V the 17 kA still covers most industrial distribution needs.
Thermal derating and panel fit
The breaker carries 250 A continuously up to 50 °C ambient. Above that it derates: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If your panel runs hot — say a sealed enclosure near a furnace line — that 223 A at 70 °C is the figure to size against, not the 250 A nameplate. Maximum power loss is 57 W, which matters for enclosure thermal calculations. Physical dimensions: 105 mm wide, 158 mm tall, 70 mm deep. That 105 mm width is standard for a 3-pole MCCB in this class — it fits the common DIN-rail or panel-mount footprint without surprises. The 70 mm depth leaves room for rear busbar connections in a typical distribution cabinet.