What this 400 A MCCB delivers in the panel
The Siemens 3VA2340-7HL32-0KC0 is a 3-pole SENTRON molded case circuit breaker rated for 400 A continuous at 40 °C — that's the full frame current, not a derated number. At 240 V it interrupts up to 330 kA, which covers most utility-transformer fault levels without cascading upstream. The 138 mm width and 248 mm height fit standard MCCB panel cutouts; depth at 110 mm leaves room for rear-connection hardware. This is a line-protection design (not motor-protection), so the thermal-magnetic curve is shaped for feeder and distribution duty. The integrated shunt trip (STL) and two HQ auxiliary switches let you wire remote trip and status feedback into the safety circuit or PLC without adding external accessories.
Breaking capacity — what the numbers mean for fault duty
The 3VA2340-7HL32-0KC0 carries a 330 kA interrupting rating at 240 V, dropping to 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V. That steep roll-off above 500 V is typical for a 400 A frame — the arc energy at 690 V limits the interruption capability. For a 480 V distribution panel in North America, the 187 kA figure still handles most high-fault scenarios. The 7.5 kA at 690 V means this breaker is not the right choice for 690 V primary feeds; you'd step up to a higher-frame SENTRON for that.
Thermal derating — continuous current across the ambient range
The 400 A rating holds flat from 40 °C through 50 °C. At 55 °C it derates to 385 A, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. Maximum operating temperature is 70 °C; storage range is -40 °C to 80 °C. If the panel ambient runs above 50 °C, size the load at the derated current — the breaker won't nuisance-trip on a warm day.