What this 400 A MCCB carries
The Siemens SENTRON 3VA2340-7HN32-0HC0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, designed for line protection in distribution panels. Breaking capacity reaches 330 kA at 240 V AC, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V — the 690 V figure is the limit for this frame, so verify SCCR against your transformer secondary or generator fault current. It ships with a shunt trip release (STL) for remote opening and two HQ auxiliary switches for status feedback to a PLC or annunciator. Power loss at rated load is 96 W maximum — account for that in enclosure thermal calculations, especially in a sealed cabinet with other heat sources.
Thermal derating and panel fit
The breaker holds full 400 A up to 50 °C ambient; above that it derates linearly to 340 A at 70 °C. Dimensions are 248 mm high, 138 mm wide, 110 mm deep — the 138 mm width is the standard 3-pole MCCB footprint for this SENTRON frame, so it drops into existing panel cutouts and busbar arrangements sized for the 3VA2 platform. Operating range is -25 °C to 70 °C; storage from -40 °C to 80 °C.