What this MCCB is and what the ratings mean for fit
The Siemens SENTRON 3VA2340-6HL32-0DC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 400 A at 40 °C. That 400 A holds flat through 50 °C — only above 55 °C does it begin to derate, dropping to 385 A at 55 °C and 340 A at 70 °C, so the thermal margin is generous for most panel environments. The ETU320 electronic trip unit gives you adjustable overload and short-circuit protection curves, which matters for selectivity coordination downstream. The interrupting ratings are the headline: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. At 415 V, that 187 kA SCCR means this breaker can safely clear a fault of that magnitude without cascading upstream — critical for high-fault installations like transformer secondaries or large motor control centers. Rated insulation voltage Ui is 800 V, and the part includes an undervoltage release and two HQ auxiliary switches. The front face carries IP40 protection — suitable for general panel mounting, not washdown environments.
Physical footprint and panel integration
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That 110 mm depth is the overall body — it fits standard MCCB mounting footprints in distribution panels and switchgear cubicles. The 138 mm width for a 3-pole 400 A frame is typical for this class; verify the bus-bar spacing and phase barriers in your existing panel layout before committing the BOM line.
Power loss and thermal management
Maximum power loss is 98.5 W at rated current. That heat has to be rejected inside the enclosure — factor it into your panel thermal calculation, especially if the MCCB is grouped with other high-current devices. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.