The Siemens SENTRON 3VA2340-5HN32-0AF0 is a 3-pole molded case circuit breaker rated for 400 A continuous and designed for line protection. Its interrupting capacity hits 187 kA at 240 V, 121 kA at 415/440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — so it handles high-fault utility feeds and transformer secondaries without cascading upstream. The 400 A rating holds flat up to 50 °C, then derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C; that thermal curve matters if the breaker sits in a warm enclosure or near other heat sources.
Integration and fit
Dimensions are 138 mm wide, 248 mm high, 110 mm deep — a standard MCCB footprint for 400 A frames. Mounts on a DIN rail or directly to a backplate with the supplied hardware. The built-in 1 auxiliary switch plus 1 trip alarm switch (HQ design) gives you a closed/open status and a separate fault signal without adding external accessories. Max power loss is 96 W, so factor that into enclosure ventilation if the panel is tightly packed.