The Siemens SENTRON 3VA2340-5HL42-0CH0 is a 4-pole molded case circuit breaker rated for 400 A continuous current (Iu) at 40 °C, with a rated insulation voltage of 800 V. Its interrupting capacity hits 187 kA at 240 V and 121 kA at 415 V or 440 V, dropping to 17 kA at 690 V — numbers that tell you this is built for high-fault utility feeds or large transformer secondaries, not branch circuits.
Thermal derating — the real-world number
Rated 400 A from 40 °C through 50 °C, it starts to pull back at 55 °C (385 A), then 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. The maximum power loss is 98.5 W, so ventilation matters in a sealed enclosure.
The auxiliary contact block (2 aux + 1 trip alarm) and the integrated undervoltage release are factory-fitted; the separate auxiliary trip (3VA9608-0BB24) is listed as a supplied component. No communication or phase-failure detection on this variant.