What this MCCB is and what it does
The Siemens 3VA2325-5MN32-0CA0 is a SENTRON molded case circuit breaker (MCCB) built for motor protection duty — not just branch-circuit fault interruption, but the kind of overload and phase-loss protection a motor load needs to keep from cooking windings. It's a 3-pole unit rated for 250 A continuous current, and it carries an ETU350M electronic trip unit that gives you adjustable overload and short-circuit protection curves, plus phase-failure detection built in. That phase-failure detection is important out here in the grease: a motor running on two phases draws high current on the remaining legs and burns up fast if the breaker doesn't catch it. This one does. It also comes with an undervoltage release (UVR) as part of the package — part number 3VA9608-0BB24 for the integrated auxiliary trip. That means if your control voltage drops out, the breaker opens without waiting for a fault. Handy for coordinated start/stop sequences or safety interlocks where you want the motor off when the control power goes away.
Breaking capacity — the real-world fault current it can handle
Breaking capacity is where this breaker earns its keep in heavy industrial panels. At 240 V it's rated 187 kA; at 415 V and 440 V it holds at 121 kA; at 500 V it's 75.6 kA; and at 690 V it's still 17 kA. Those numbers mean it can safely interrupt very high fault currents without welding contacts or venting plasma — important when the transformer feeding your panel is big and the available fault current is high. The 690 V rating at 17 kA also tells you it's usable on 600 V class systems common in North American mining and oilfield installations.
Thermal derating — how hot can your panel get?
The 250 A continuous rating holds all the way up to 50 °C ambient. Above that it starts to step down: 240 A at 55 °C, 235 A at 60 °C, 230 A at 65 °C, and 225 A at 70 °C. That's a shallow derating curve — you lose only 25 A over a 20 °C rise from 50 to 70 °C. So if your panel runs warm because it's packed tight or sitting next to a hot process line, this breaker still carries most of its rated current. The maximum operating temperature is 70 °C, and storage range goes from -40 °C to 80 °C. Power loss at full load is 40 W maximum. That's not trivial — in a sealed enclosure with multiple breakers, that heat adds up. Plan your ventilation or enclosure sizing accordingly.
Physical fit and panel integration
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That's a standard 3-pole MCCB footprint for the SENTRON 3VA2 frame size. It mounts via the breaker's own base — no DIN rail adapter needed for this class of breaker; it bolts directly into the panel or onto a mounting plate. The 138 mm width means it occupies three 45 mm pole spaces if you're laying out a multi-breaker lineup.
What it doesn't have — and why that matters for your BOM
No auxiliary contact version is included, no ground-fault monitoring, no communication function, and no voltage-trigger feature. If your application requires any of those, you'd need a different variant in the 3VA2 family or an add-on module. The trip indicator is also absent, so there's no local mechanical flag showing whether the breaker tripped on overload or was manually opened. That's typical for the base motor-protection configuration — the ETU350M handles the protection logic, and you get the status from the undervoltage release circuit.