The Siemens 3VA2340-5HN32-0DH0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 400 A at 40 °C through 50 °C ambient — it holds that full rating without derating up to 50 °C, then steps down to 385 A at 55 °C and 340 A at 70 °C. Breaking capacity is the headline: 187 kA at 240 V AC, 121 kA at 415/440 V, 75.6 kA at 500 V, and 17 kA at 690 V. The ETU350 electronic trip unit gives adjustable long-time, short-time, and instantaneous protection curves, plus ground-fault capability (though this variant ships without the ground-fault module fitted).
Mounting is via four screws to a backplate or DIN-rail adapter. The 15 000 mechanical endurance cycles (latching) are typical for a fixed-mounted MCCB at this frame size — not a daily-switching device, but fine for backup protection and infrequent maintenance isolation.