This Siemens SENTRON 3VA2125-7MN36-0AA0 is a molded case circuit breaker built for motor protection — not just a thermal-magnetic for branch circuits. Rated 25 A continuous at up to 70 °C ambient without derating, it holds its full current rating across the entire operating temperature range. That means no up-tower swaps if the panel gets hot in summer. The adjustable trip class (10A, 10E, or 20E) lets you match the breaker to the motor start profile: 10A for short starts like pumps, 20E for high-inertia loads like fans or centrifuges.
Breaking capacity and voltage ratings
Breaking capacity is voltage-dependent: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.7 kA at 690 V. The 690 V figure looks low, but that's because the breaker is designed for 480 V class systems — at 690 V you'd typically step up to a higher-rated frame. The rated insulation voltage is 800 V, so the internal clearances handle the high-side transient without tracking.
Environmental and physical fit
Dimensions: 105 mm wide, 181 mm tall, 86 mm deep. That's a standard 3-pole MCCB footprint — fits a typical DIN-rail or panel-mount enclosure without surprises. Operating temperature from -25 °C to 70 °C; storage from -40 °C to 80 °C. Phase failure detection is built in, so it will trip on a lost phase — critical for motor protection where single-phasing burns windings. Power loss is only 0.6 W maximum, negligible for panel thermal budgeting.