What this MCCB delivers — and where the ratings matter
The Siemens SENTRON 3VA2225-5HN32-0KL0 is a 3-pole molded case circuit breaker rated for 250 A continuous current, built for line protection duty. The interrupting capacity tells the real story: 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. That 187 kA figure at 240 V means this breaker can safely clear a bolted fault on a high-capacity transformer secondary without the arc re-striking or the case rupturing — critical for main or feeder positions where available fault current is high. The ETU350 electronic trip unit gives you adjustable long-time, short-time, and instantaneous protection curves, so you can coordinate downstream breakers without nuisance trips.
Thermal derating — don't ignore the ambient curve
The 250 A rating holds flat from 40 °C to 50 °C. At 55 °C it derates to 241 A, at 60 °C to 232 A, at 65 °C to 222 A, and at 70 °C to 213 A. If this breaker lives in a crowded panel or near heat-generating gear, size the continuous load against the derated value at your actual ambient — not the 250 A nameplate. Maximum power loss is 48 W, which adds to the enclosure heat budget.
Auxiliary wiring and trip accessories
This variant ships with a shunt trip (STL) release and a full auxiliary contact set: 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch (HQ type). The integrated auxiliary trip module is order code 3VA9688-0BL33; the basic switch without accessories is 3VA2225-5HN32-0AA0. No undervoltage release, no ground-fault monitoring, no communication module — this is a straightforward line-protection breaker with remote trip capability via the shunt.