400 A MCCB with ETU560 — what the ratings mean for fit
The Siemens SENTRON 3VA2340-5JQ32-0KC0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with an ETU560 electronic trip unit. That 400 A holds flat through 50 °C; above that, derate to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C (–). For a panel builder, this means the breaker can sit in a warm enclosure without losing headroom until the ambient crosses 50 °C — the thermal curve is published, so the sizing calc is straightforward. Breaking capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V (–). That 187 kA at 240 V covers high-fault utility feeds; the 17 kA at 690 V still clears most industrial motor-drive faults. The ETU560 electronic trip gives you adjustable long-time, short-time, instantaneous, and ground-fault protection — the ground-fault monitoring uses summation current formation on the L-conductor. Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The 138 mm width is standard for a 400 A frame in the SENTRON 3VA2 family — it fits the same panel cutout as other 3VA2 breakers, so a swap from a different trip unit or accessory set doesn't require re-drilling the mounting plate.
Integrated accessories and compliance
The breaker ships with a shunt trip release (STL) and two HQ auxiliary switches. The shunt trip allows remote tripping from a PLC or emergency-stop circuit; the auxiliary switches provide status feedback for the panel controller. The integrated basic switch is order code 3VA2340-5JQ32-0AA0, and the auxiliary trip module is 3VA9688-0BL33 — these are the internal sub-assemblies, not field-installable kits. Rated insulation voltage is 800 V. 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 that into enclosure thermal calculations. No undervoltage release, no phase-failure detection, no trip indicator. Communication function is present, which on the ETU560 typically means PROFIBUS or PROFINET via a communication module — confirm the specific protocol with the order code suffix.