What ships in the carton
The Siemens SENTRON 3VA2340-5HN42-0BH0 is a 4-pole molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, with a maximum interrupting capacity of 187 kA at 240 V. It ships with an integrated undervoltage release (UVR) and a factory-fitted auxiliary switch block: 2 auxiliary switches plus 1 trip alarm switch HQ. The kit is complete — no loose accessories to chase down.
Interrupting capacity and selectivity
At 240 V this breaker clears 187 kA — that is the full short-circuit rating for a 400 A frame, giving the site electrical engineer headroom for high-fault panels. At 415 V and 440 V it still holds 121 kA, dropping to 75.6 kA at 500 V and 7.5 kA at 690 V. The 400 A frame means the thermal-magnetic trip unit is sized for the main feeder, not a branch; selectivity with downstream 3VA2 breakers requires a coordination study, but the interrupting curve is published for that work.
Thermal derating and panel fit
Continuous current holds at 400 A from 40 °C through 50 °C ambient. Above that it derates linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, 340 A at 70 °C. The body dimensions — 248 mm high, 184 mm wide, 110 mm deep — fit a standard MCCB cutout; the 110 mm depth leaves clearance for rear-access cable connections in a 600 mm deep enclosure. Power loss at full load is 98.5 W, so account for that heat in the panel thermal budget.