The Siemens SENTRON 3VA2340-8KP32-0AA0 is a 3-pole molded case circuit breaker rated 400 A continuous at 40 °C, built around the ETU850 electronic trip unit. That 400 A holds flat through 50 °C — you only start derating above 55 °C, dropping to 300 A at 70 °C. For a 400 A feeder in a warm enclosure, that thermal headroom matters more than the raw number. Interrupting capacity is 440 kA at 240 V, 330 kA at 415 V, and still 52.5 kA at 690 V. The ETU850 trip unit supports communication, so this breaker can report status and trip events over the plant network — useful for a maintenance team that wants to know which feeder cleared without walking the panel. No undervoltage release and no ground-fault monitoring are fitted as standard; those are add-on options if your coordination study calls for them.
Maximum power loss is 96 W. In a sealed enclosure with multiple breakers, that heat needs to be factored into the thermal calculation — especially if you're running near the 70 °C upper operating limit.