What this 250 A MCCB actually does in a panel
The Siemens 3VA2325-6HN32-0JL0 is a 3-pole molded case circuit breaker from the SENTRON 3VA2 series, rated for a continuous current of 250 A and built for line protection duty. Its ETU350 electronic trip unit gives you adjustable overload and short-circuit protection curves, so it handles feeder or main breaker roles in distribution panels. The 242 kA breaking capacity at 240 V means it can interrupt very high fault currents without upstream fuses — useful where the utility transformer sits close to the switchboard. At 415 V and 440 V it still holds 187 kA, and at 690 V it breaks 40 kA, so this breaker covers low-voltage distribution across most industrial voltage levels. The auxiliary contact package comes as 2 auxiliary switches plus 1 trip alarm and 1 electrical alarm switch (HQ type), which gives you remote status indication on the trip event and breaker position — handy for a PLC input or a panel lamp circuit. A shunt trip release (STL) is integrated, so you can remotely trip the breaker via a control signal, which is standard for emergency-stop or fire-safety interlocks.
Sizing and thermal derating
The breaker holds its full 250 A rating up to 50 °C ambient. Above that it derates: 240 A at 55 °C, 235 A at 60 °C, 230 A at 65 °C, and 225 A at 70 °C. If your panel runs hot — say near a drive cabinet or in a non-ventilated enclosure — factor that derating into the load calculation. The operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. Physical footprint: 248 mm high, 138 mm wide, 110 mm deep. That depth is the body only — add clearance for the handle throw and wiring gutters. It mounts on a DIN rail or directly to a panel backplate; the 138 mm width is three pole spaces at roughly 46 mm per pole, which is standard for this class.