What this MCCB carries — and what it means for your panel
The Siemens 3VA1225-6EF42-0JH0 is a SENTRON molded case circuit breaker rated 250 A continuous at 40 °C, with a 220 kA interrupting capacity at 240 V — that's the SCCR you'd spec for a main feeder on a high-fault industrial service, not a branch device. Four poles handle three-phase plus neutral, and the 800 V rated insulation voltage means it's comfortable on 480 V or 600 V class systems without derating the insulation. The interrupting curve drops to 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V (–) — so the real-world fault-clearing headroom stays high even on 480 V delta services. This is a line-protection design, meaning it's built for feeder duty rather than motor or generator protection — the trip curve and accessories are selected for cable and busbar protection. The 57 W maximum power loss is worth factoring into a sealed enclosure's thermal budget; at full load that's real heat to vent.
Auxiliaries and releases — what's on board
Factory-fitted with a shunt trip release (STL) and a 2-auxiliary-switch plus 1-trip-alarm-switch configuration. The shunt trip lets you remotely open the breaker via a control signal — standard for emergency-stop circuits or interlocked feeder schemes. The trip alarm switch gives a dedicated signal when the breaker trips on fault, separate from the aux contacts that follow the handle position. No undervoltage release and no ground-fault monitoring module on this variant; if you need those, this isn't the order code.
Mounting and dimensions — fits the standard MCCB footprint
At 70 mm deep, 140 mm wide, and 158 mm tall, this breaker fits the standard 4-pole SENTRON 3VA frame size for the 250 A class. Panel cutout and busbar spacing follow the Siemens pattern — if your panel is already drilled for a 3VA1110 or 3VA1112 frame, the 3VA1225 is a different frame height and width, so it won't drop in without re-drilling the mounting holes or adjusting the busbar takeoff points. Verify the backplate layout before committing the BOM.