The Siemens SENTRON 3VA2340-6HL32-0AF0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels. Its adjustable thermal-magnetic trip unit covers a 600 A to 4,000 A range, meaning you set the instantaneous pickup to match the downstream cable or bus — not a fixed value that forces an oversized breaker onto a smaller load. Out here in the grease, that adjustability saves a panel re-spin when the load calc comes in a little under the max.
Breaking capacity — what the voltage columns tell you
This MCCB delivers 242 kA at 240 VAC, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. The steep drop at 690 V is the giveaway that this is a 600 V class frame pushed to its limit — don't spec it for a 690 V primary feeder unless the fault current is well under 7.5 kA. For a 480 V plant main or a 400 V distribution board, the 187 kA headroom covers most utility-transformer secondary faults without needing a current-limiting fuse upstream.
Thermal derating — the real ampacity in a hot panel
The 400 A rating holds from 40 °C through 50 °C ambient. At 55 °C it drops to 385 A, at 60 °C to 370 A, at 65 °C to 355 A, and at 70 °C to 340 A. If this breaker sits next to a transformer or a row of contactors that push the enclosure air above 50 °C, size the feeder for the derated number — the nameplate 400 A is only good in a cool cabinet.
Physical fit and auxiliary wiring
The case measures 138 mm wide, 248 mm tall, and 110 mm deep — a standard 3-pole MCCB footprint for a 400 A frame. It ships with one auxiliary switch and one trip alarm switch (HQ type) factory-installed, so you get a remote open/closed and a trip signal without adding a separate accessory block. Power loss at full load is 96 W; plan for that heat in the enclosure ventilation calc.