What this 400 A MCCB carries
The Siemens SENTRON 3VA2340-6HN32-0KC0 is a 3-pole molded case circuit breaker rated for 400 A continuous at 40 °C, designed for line protection in distribution panels. It delivers 242 kA interrupting capacity at 240 V AC and still holds 187 kA at 415 V and 440 V — enough headroom for high-fault utility feeds or transformer secondaries. At 690 V it drops to 7.5 kA, which still clears most motor-circuit faults in that voltage class.
Thermal derating and panel fit
Full 400 A rating holds through 50 °C ambient; above that it derates linearly to 340 A at 70 °C. That curve matters if this breaker sits in a crowded enclosure or near other heat sources — the 96 W maximum power loss adds to the internal temperature rise. Dimensions are 248 mm tall, 138 mm wide, 110 mm deep — a standard MCCB footprint for 400 A frame size, so it swaps into existing SENTRON or comparable panel layouts without re-drilling the mounting plate.