400 A MCCB with undervoltage release — what the ratings mean
The Siemens 3VA2340-5HN32-0BA0 is a SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous current, holding that rating from 40 °C up to 50 °C before derating begins — at 55 °C it's still good for 385 A, and at 70 °C it delivers 340 A. Breaking capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V. No auxiliary switch, no ground-fault monitoring. The UVR means the breaker trips automatically when supply voltage drops below a threshold, which is standard for motor feeder protection where you want to prevent automatic reclosure after a dip.
Dimensions are 248 mm high, 138 mm wide, 110 mm deep — a standard 3-pole MCCB footprint for a 400 A frame. Maximum power loss is 98.5 W at rated current. That's the heat you need to vent in the enclosure — factor it into your thermal calculation if the panel is sealed or has multiple breakers in a row.