What the ratings mean for your panel
The Siemens 3VA2225-5KP32-0JC0 is a SENTRON molded case circuit breaker (MCCB) rated for 250 A continuous current at 40 °C through 50 °C — meaning it carries a full 250 A load without derating in a typical 40 °C panel ambient. Above that, the thermal curve steps down: 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If your enclosure runs hot, size the breaker for the actual ambient, not the nameplate. Interrupting capacity is what decides whether this breaker clears a fault without exploding. At 240 V it handles 187 kA; at 415 V and 440 V, 121 kA; at 500 V, 79 kA; at 690 V, 5.1 kA. That 187 kA at 240 V tells you it is built for high-fault panels — think transformer secondaries or large motor control centers where available fault current is serious. The 5.1 kA at 690 V is the weak point; if your system runs 690 V with high fault current, this is not the breaker for that bus. Rated insulation voltage Ui is 800 V, and the breaker carries an ETU850 electronic trip unit with communication function — so it can talk to a higher-level system for power monitoring or remote trip indication. The auxiliary contact version is 2 auxiliary switches HQ, and the integrated auxiliary trip is a shunt trip (STL) design. No undervoltage release, no phase failure detection, no ground fault monitoring on this variant.
Panel fit and physical integration
Dimensions: 105 mm wide, 181 mm high, 86 mm deep. That 105 mm width is a standard 4-module footprint for a 3-pole MCCB in the SENTRON range — it fits the same mounting base as other 3VA2 3-pole breakers. The 86 mm depth means it clears most standard enclosure backplates without a deep gland plate. Maximum power loss is 48 W. In a sealed, non-ventilated enclosure, that heat has to be accounted for in the thermal design. If you are packing multiple breakers in a small cabinet, derate per the ambient curve above or add forced ventilation. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The latching endurance is rated at 20,000 operations — mechanical life, not electrical. For frequent switching duty, check the electrical endurance curve against your load type.