The Siemens SENTRON 3VA2440-6HN32-0HL0 is a 3-pole molded case circuit breaker rated for 400 A continuously at ambient temperatures from 40 °C through 70 °C without derating — the full 400 A holds across that entire thermal band, so you don't need to oversize for a warm panel. Its interrupting capacity reaches 242 kA at 240 V AC, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 9 kA at 690 V, meaning it can safely clear fault currents at those levels without upstream cascading.
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep — a standard footprint for a 400 A frame in the SENTRON 3VA family. It mounts directly into a switchboard or distribution panel via the rear studs; no DIN-rail adapter is used at this frame size. The 3-pole design occupies a single unit width. Maximum power loss is 63.5 W, which should be factored into the enclosure thermal budget.