What it is and what it does
The Siemens SENTRON 3VA2440-5MN32-0KC0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, designed for motor protection. It carries a shunt trip release (STL) and two HQ auxiliary switches factory-fitted, plus phase failure detection built in.
Ratings that matter for the panel
The 400 A rating holds flat across the entire 40 °C to 70 °C ambient range — no derating curve to chase. That's unusual and simplifies panel design in warm enclosures. The 110 mm depth and 138 mm width on a 248 mm tall frame mean it fits standard SENTRON mounting footprints; if you're swapping into an existing 3VA lineup, the mechanical lug centers and bus-bar pitch stay consistent.
Physical and environmental limits
Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 63.5 W — relevant for enclosure thermal calculations if you're stacking multiple breakers. The voltage trigger is present; undervoltage release is not fitted on this variant.