What this 400 A MCCB carries — and where it stops
The Siemens SENTRON 3VA2340-7HL32-0HC0 is a 3-pole molded case circuit breaker rated for 400 A continuous current, sized for line protection in distribution panels. Its interrupting capacity hits 330 kA at 240 V and 242 kA at 415 V or 440 V, then drops to 187 kA at 500 V and 7.5 kA at 690 V — that steep fall at 690 V is the real constraint if you are feeding a 690 V drive or transformer primary. The breaker carries a shunt trip (STL) and two HQ auxiliary switches built in, so you get remote trip capability and status feedback without an add-on module.
Thermal derating — the number that decides the real load
The 400 A rating holds flat from 40 °C up to 50 °C. At 55 °C it derates to 385 A, at 60 °C to 370 A, at 65 °C to 355 A, and at 70 °C to 340 A. If your panel ambient runs hot — say a sealed enclosure next to a furnace line — you are effectively buying a 340 A breaker at the top of its operating range. The maximum operating temperature is 70 °C, storage range -40 °C to 80 °C.
Footprint and panel fit
Dimensions are 248 mm high, 138 mm wide, 110 mm deep — a standard 3-pole MCCB footprint for this current class. No trip indicator on the front face, so fault indication relies on the auxiliary switch feedback. The basic switch core is order code 3VA2340-7HL32-0AA0, meaning this variant adds the shunt trip and aux switches at the factory rather than as field-installed accessories.