The Siemens SENTRON 3VA2340-5JP32-0HH0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C through 50 °C, with a 187 kA interrupting capacity at 240 V — that means it can safely clear a fault up to 187,000 A at that voltage without welding contacts or rupturing the case, which is the figure that governs SCCR compliance for the downstream panel. The interrupting curve drops to 121 kA at 415 V and 440 V, then to 75.6 kA at 500 V, and 7.5 kA at 690 V — so if your service voltage is 480 V or 600 V class, the 75.6 kA or 7.5 kA figure is the one that matters for coordination studies. Above 50 °C ambient, the continuous current derates linearly: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C — so if this breaker lives in a hot enclosure or near a heat source, use the derated value, not the 400 A nameplate.
It's a line-protection design (not a motor-protection or generator breaker), so it's intended for feeder and main applications in distribution panels — that's another SKU I don't need to worry about going obsolete mid-project.