400 A MCCB for line protection — what the ratings mean for your panel
The Siemens SENTRON 3VA2340-6HL32-0KH0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, with a breaking capacity of 242 kA at 240 V. That 242 kA figure means it can safely interrupt a fault current up to that level without welding contacts or cascading damage upstream — critical for high-fault installations like transformer secondaries or large motor control centers. At 415 V and 440 V the rating holds at 187 kA, and at 500 V it still delivers 121 kA; only at 690 V does it drop to 7.5 kA, so confirm your system voltage against the curve. The continuous current is flat at 400 A from 40 °C through 50 °C, then derates linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel ambient runs above 50 °C, size the load to the derated value, not the nameplate 400 A.
Built-in accessories — shunt trip and auxiliary switches
This variant ships with a shunt trip (STL) for remote tripping and a complement of 2 auxiliary switches plus 1 trip alarm switch (HQ). The shunt trip lets a safety PLC or E-stop circuit open the breaker without a manual action — useful for emergency-off chains or remote load shedding. The auxiliary switches provide status feedback to the control system; the trip alarm switch signals a fault trip separately from a manual open. No undervoltage release or ground-fault monitoring is fitted on this order code. If you need UVR or GF protection, that requires a different variant or an add-on module.
Dimensions and panel fit
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep (9.76 × 5.43 × 4.33 inches). That depth includes the arc chamber and terminals; plan for additional clearance behind the panel for wiring and the shunt trip leads. The 3-pole footprint matches standard SENTRON 3VA2340 mounting patterns — no adapter plate needed for a panel designed around the same frame size.