Siemens SENTRON 3VA2340-6HN32-0AA0 — 400 A MCCB with ETU350 Trip Unit
The Siemens SENTRON 3VA2340-6HN32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, designed for line protection in distribution panels and switchgear assemblies. It carries an ETU350 electronic trip unit, which provides adjustable overload and short-circuit protection curves — suitable for coordinating with downstream breakers in selective coordination schemes. Breaking capacity is rated at 242 kA at 240 V AC, 187 kA at 415/440 V, 121 kA at 500 V, and 7.5 kA at 690 V — the 690 V figure governs the high-voltage end of the application envelope and is the limiting value for systems above 500 V. The insulation voltage is rated at 800 V, and the front face carries IP40 protection — suitable for enclosed panel mounting where the front is operator-accessible but the live parts remain behind the door.
Current Derating and Thermal Performance
The breaker holds its full 400 A rating up to 50 °C ambient. Above that, derating applies: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. For a panel that runs warm, the 55 °C figure is the one to size against. Maximum power loss is 96 W at rated current — a factor for enclosure thermal calculations, particularly in sealed or high-density cabinets. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Physical Fit and Mounting
Dimensions are 248 mm height, 138 mm width, 110 mm depth — a standard 3-pole MCCB footprint for the 400 A frame class. Verify the mounting hole pattern and busbar spacing against the existing panel layout before ordering. The breaker does not include an undervoltage release, voltage trigger, or ground-fault monitoring module as standard — these are external accessories if required.