The Siemens SENTRON 3VA2340-5HN32-0CA0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels. It carries a 187 kA interrupting capacity at 240 V AC and 121 kA at 415 V AC, so it handles high-fault utility feeds without cascading upstream.
Derating and thermal reality
The 400 A rating holds at ambient up to 50 °C. Above that it steps down: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, 340 A at 70 °C. The maximum power loss is 98.5 W, which factors into enclosure thermal calculations. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
The breaker measures 248 mm high, 138 mm wide, 110 mm deep. No auxiliary switch fitted (the -0CA0 variant leaves that off), but the undervoltage release is built in.