What this MCCB carries and where it fits
The Siemens SENTRON 3VA2325-5HN32-0KA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current at 40 °C, with a rated insulation voltage of 800 V. It's the line protection variant — meaning it's configured for feeder and main breaker duty rather than motor protection — and ships with the ETU350 electronic trip unit and a shunt trip (STL) auxiliary release. The breaking capacity numbers tell the real story here: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That's high-interrupting capacity for a 250 A frame — it handles fault currents that would vaporize a standard MCCB, so it's sized for large transformer secondaries or high-fault industrial distribution. Physically it measures 248 mm high by 138 mm wide by 110 mm deep — a standard 3VA2 frame footprint that drops into the same panel cutout as other 3VA2 breakers. The depth is 110 mm, so verify gland-plate clearance if the panel is shallow.
Thermal derating and trip unit
Rated 250 A at 40 °C, 45 °C, and 50 °C — no derating needed up to 50 °C. Above that it steps down: 240 A at 55 °C, 235 A at 60 °C, 230 A at 65 °C, 225 A at 70 °C. If the panel ambient runs hot, that 225 A at 70 °C figure is the one to design around. The ETU350 electronic trip unit handles the overcurrent protection curves. No undervoltage release, no ground-fault monitoring, no communication module — this is a straightforward line-protection breaker with a shunt trip for remote opening. The shunt trip is the 3VA9688-0BL33 integrated auxiliary trip. Maximum power loss is 37.5 W — account for that in enclosure thermal calculations if the panel is densely packed.