400 A MCCB with 242 kA interrupting — what the ratings mean for your panel
The Siemens SENTRON 3VA2340-6HL32-0AE0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with a maximum interrupting capacity of 242 kA at 240 V AC. That 242 kA figure means it can safely clear a bolted fault of that magnitude without rupturing — critical for high-fault installations like transformer secondaries or large motor control centers where available fault current exceeds 100 kA. The breaker carries its full 400 A rating up to 50 °C; above that it derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. For a buyer freezing a BOM, the 400 A continuous rating at 40 °C ambient is the line item spec — confirm your panel ambient stays under 50 °C to avoid derating. This is the line protection variant, meaning the ETU320 electronic trip unit is configured for overload and short-circuit protection of feeders and distribution circuits — not motor protection with overload class or phase-loss detection. The ETU320 lacks voltage triggering, phase failure detection, and communication functions. It ships with four HQ auxiliary switches and provisions for an integrated auxiliary trip and a basic switch if field retrofits are needed.
Environmental and compliance
Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. Maximum power loss at rated current is 96 W — factor this into enclosure thermal calculations. The SENTRON series carries IEC 60947-2 certification for molded case circuit breakers; compliance documentation (CE, RoHS, REACH) is standard with Siemens shipments. No UL/CSA listing is stated in the evidence — verify with your Siemens representative if UL 489 listing is required for your jurisdiction.