What this MCCB is and what the ratings mean
The Siemens 3VA2340-6HN32-0HL0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) rated for line protection, 400 A continuous at 40 °C, three poles, with an ETU350 electronic trip unit. The interrupting ratings are what matter for the fault-current study: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V — so it can sit on a high-fault panel main or feeder without upstream fuses as long as the available fault current stays under those numbers. The ETU350 release gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves — it's a full electronic trip, not a thermal-magnetic, so coordination with downstream breakers is repeatable and field-adjustable without swapping trip units. It carries a shunt trip (STL) as the auxiliary release, plus a set of auxiliary switches: 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch (HQ configuration). That's enough for remote status and trip indication back to a PLC or SCADA without an add-on module.
Integration and mounting
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep — a standard 3-pole MCCB footprint for a 400 A frame. It mounts on a panel backplate via screw terminals; no DIN rail, so plan for a drilled-and-tapped mounting pattern. Rated insulation voltage is 800 V, and the operating temperature range is -25 °C to 70 °C, with derating above 55 °C: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, 340 A at 70 °C. If the panel ambient runs hot, the continuous current drops — factor that into the load calculation. Maximum power loss is 96 W — that's heat that stays inside the enclosure, so verify the panel's thermal dissipation if you're packing several breakers in a compact cabinet.