What this MCCB carries and where it fits
The Siemens SENTRON 3VA2440-6HN32-0AG0 is a 3-pole molded case circuit breaker rated for 400 A continuous current (Iu) and a rated insulation voltage of 800 V. It's configured for line protection — meaning it's the main feeder breaker in a distribution panel, not a motor-protective device. The ETU350 electronic trip unit gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves, so you can coordinate selectivity downstream without swapping trip units. Breaking capacity is the headline here: 242 kA at 240 V AC, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. That's high-interrupting capability — it handles fault currents from a large transformer without needing a current-limiting upstream device. For a 400 A frame, those numbers put it in the top tier of SCCR headroom. Thermal derating is published: full 400 A up to 50 °C ambient, then 384 A at 55 °C, 376 A at 60 °C, 368 A at 65 °C, and 360 A at 70 °C. If your panel runs hot — say, near a transformer or in a non-climate-controlled enclosure — size the load side for the derated figure, not the nameplate 400 A.
Panel integration and auxiliary wiring
Dimensions: 248 mm high, 138 mm wide, 110 mm deep. Auxiliary contact configuration: one auxiliary switch plus one trip alarm switch (HP type). That gives you one N/O or N/C for status feedback and one dedicated to signaling a trip event. No undervoltage release, no voltage trigger, no communication function, no phase-failure detection — this is a basic line-protection breaker with no add-on electronics. If you need remote monitoring or undervoltage protection, you'll add those as external modules. Maximum power loss is 63.5 W — that's the heat the breaker dissipates at full rated current. In a sealed enclosure, factor that into your thermal budget; it's not a lot for a 400 A frame, but it's not negligible either.