What this 400 A MCCB does on the line
The Siemens SENTRON 3VA2340-6JQ32-0CL0 is a 3-pole molded case circuit breaker rated for a continuous current Iu of 400 A, with an ETU560 electronic trip unit for line protection. It carries a breaking capacity of 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 handles high-fault-current scenarios like transformer secondaries or large motor control centers without cascading upstream. The 400 A rating holds flat from 40 °C through 50 °C; above that it derates to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. That thermal curve matters if this breaker lives in a hot panel next to drives or transformers — plan your load at the ambient you actually see, not the 40 °C sweet spot.
Panel fit and auxiliaries
Dimensions are 248 mm high, 138 mm wide, 110 mm deep — a standard SENTRON 3VA frame that drops into existing panel cutouts and busbar systems for the series. The auxiliary contact block is configured as 2 auxiliary switches plus 1 trip alarm switch plus 1 electrical alarm switch (HQ type). An undervoltage release (UVR) is integrated, and the ground-fault monitoring uses summation-current formation on the L-conductor. Communication function is present, so it can talk to a higher-level control system for status and trip data. The supplied basic switch is order code 3VA2340-6JQ32-0AA0, and the integrated auxiliary trip is 3VA9608-0BB24 — useful to know if you're ordering spares or a replacement subassembly.