What this MCCB carries and where it fits
The Siemens SENTRON 3VA2340-5HL42-0CA0 is a 4-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with an interrupting capacity of 187 kA at 240 V AC and 121 kA at 415/440 V. That 187 kA figure at 240 V means it can clear a bolted fault on a large step-down transformer secondary without the arc quenching failing — it's sized for high-available-fault-current panels, not light commercial gear. The continuous rating holds flat at 400 A up to 50 °C, then derates to 385 A at 55 °C and 340 A at 70 °C, so you don't lose headroom unless the cabinet runs hot. It ships with an undervoltage release (UVR) fitted; the basic switch is order code 3VA2340-5HL42-0AA0.
Breaking capacity and selectivity — the real numbers
At 240 V it's rated 187 kA, at 415 V and 440 V it's 121 kA, at 500 V it drops to 75.6 kA, and at 690 V it's 7.5 kA. That steep roll-off above 500 V means this breaker is optimized for 400/480 V distribution — not for 690 V motor circuits. If you're coordinating downstream breakers, the 121 kA at 415 V gives you room to run a full-rated main on a 100 kA panel without cascading. The minimum breaking capacity is 600 A, so it's not for tiny branch circuits.
Panel fit and integration
Dimensions are 248 mm high, 184 mm wide, 110 mm deep. That 184 mm width is a 4-pole frame — it needs a 4-module-wide cutout in a panel or a dedicated MCCB mounting base. The 110 mm depth means it clears a standard 200 mm deep enclosure backplate with room for rear-access wiring. Operating range is -25 °C to 70 °C; storage from -40 °C to 80 °C. Power loss at full load is 98.5 W — factor that into cabinet thermal calculations.