What this MCCB is and what it does
The Siemens 3VA1225-5EF42-0JC0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection — meaning it sits at the feeder or main distribution point, not downstream on a motor or branch circuit. Four poles, rated continuous current Iu of 250 A, with a TM240 thermal-magnetic release that handles overloads and short-circuits in one package. The interrupting ratings tell you where it can go: 187 kA at 240 V, 121 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V. That 187 kA figure at 240 V is high — this breaker is sized for high-fault locations like transformer secondaries or large panel mains where available fault current is serious.
Thermal derating and what it means for your panel
The 250 A rating holds flat from 40 °C through 50 °C ambient. Above that it starts to step down: 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. If your enclosure runs hot — say a packed panel with multiple breakers — you need to size the feeder for the derated value, not the nameplate 250 A. The operating range is -25 °C to 70 °C, storage from -40 °C to 80 °C.
Auxiliaries and releases built in
This variant ships with a shunt trip (STL) auxiliary release — order code 3VA9688-0BL32 for the integrated trip unit — and two auxiliary switches (HQ type) for status feedback to a PLC or indication lamp. No undervoltage release, no ground-fault monitoring, no communication module, no phase-failure detection. If you need those, this isn't the variant. The IP40 front protection means it's fine in a clean indoor panel; keep it out of washdown zones.
Physical fit and panel integration
Dimensions: 158 mm height, 140 mm width, 70 mm depth. That 70 mm depth is shallow enough for most standard distribution panels — no deep-can requirement. Four-pole footprint; mounts via the SENTRON base plate or direct panel screws. The 2 auxiliary switches HQ are wired at the factory; verify the shunt trip wiring polarity before energizing.