What this 250 A MCCB delivers — and where the ratings matter
The Siemens 3VA2225-5HN32-0AH0 is a SENTRON molded case circuit breaker rated for 250 A continuous current (Iu) across three poles, built around the ETU350 electronic trip unit. This is a line-protection breaker — no undervoltage release, no ground-fault monitoring, no communication module — so it's a straightforward main or feeder breaker for a distribution panel where you need adjustable thermal-magnetic or electronic protection curves without extra accessories. The breaking capacity tells you where this breaker can sit in the fault-current hierarchy: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V. At 415 V that's a high-interrupting rating — it handles the full fault current of a typical 400 V industrial distribution transformer without needing a current-limiting upstream device. At 690 V the 5.1 kA figure is lower; if your system runs at that voltage, verify the available fault current stays under that ceiling. Thermal derating is straightforward: full 250 A from 40 °C through 50 °C ambient, then 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. If the breaker lives in a warm enclosure — say next to a transformer or drive — the 55 °C derating point is where you start to lose headroom. Dimensions: 181 mm height, 105 mm width, 86 mm depth. It's a standard 3-pole MCCB footprint for the 3VA2 frame — fits the same panel cutout and bus-bar spacing as other 250 A SENTRON breakers. The auxiliary contact block ships as 2 auxiliary switches plus 1 trip alarm switch (HQ configuration), so you get both a status signal and a separate alarm on trip without adding a module.
Trip unit and protection features
The ETU350 is an electronic trip unit with LSIG protection — long-time, short-time, instantaneous, and ground-fault — though this specific variant ships without ground-fault monitoring (the 'Without' designation on the ground-fault version field). That means you get adjustable L, S, and I curves but no built-in ground-fault element. If you need ground-fault protection, you'd step to a different order code in the 3VA2 family. Power loss at rated current is 48 W maximum — relevant for enclosure thermal calculations if you're packing multiple breakers in a confined panel. The front face carries IP40 protection; the rest of the breaker is designed for enclosed mounting inside a switchboard or panel.