The Siemens SENTRON 3VA2440-6KQ42-0AA0 is a 4-pole molded case circuit breaker rated for 400 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling, which simplifies panel thermal budgeting in a crowded enclosure. Its breaking capacity hits 242 kA at 240 V and still holds 187 kA at 415 V and 440 V, so it handles high-fault utility feeds or transformer secondaries without cascading upstream. The ETU860 electronic trip unit gives adjustable N-conductor protection (OFF, 20% to 130%) and a communication function for integration into a plant monitoring network.
Breaking capacity and what it means for your panel
The 242 kA at 240 V is the maximum fault current this MCCB can safely interrupt at that voltage level — think a large transformer secondary or a bus feeding multiple drives. At 415 V and 440 V it still clears 187 kA, dropping to 121 kA at 500 V and 9 kA at 690 V. For most industrial 400 V distribution, 187 kA is well above typical available fault current, so you get a generous safety margin without needing a current-limiting fuse upstream.
Thermal performance and mounting
Rated 400 A from 40 °C through 70 °C ambient — no derating curve to chase. The 4-pole frame measures 184 mm wide by 248 mm tall by 110 mm deep, which fits standard switchboard cubicle mounting patterns. Front protection is IP40, so it's fine for a clean indoor panel but not for washdown areas. Maximum power loss is 63.5 W, worth accounting for in enclosure ventilation if you're packing several breakers side by side.