MCCB for high-fault panels
The Siemens SENTRON 3VA1340-6EF32-0DH0 is a 3-pole molded case circuit breaker rated 400 A at 40 °C, designed for line protection in distribution panels where fault current potential is high. Its interrupting capacity of 220 kA at 240 V and 154 kA at 415 V means it can safely clear severe short-circuit faults without upstream damage — critical for high-capacity transformer secondaries or busway taps. At 690 V the rating drops to 17 kA, so verify the available fault current at the point of installation if using on a 690 V system.
Current derating and thermal limits
The breaker carries its full 400 A rating up to 50 °C ambient; above that it derates linearly to 376 A at 65 °C and 367 A at 70 °C. Panel builders should account for this when positioning the breaker near other heat sources. Maximum power loss is 94.6 W, which feeds into enclosure thermal calculations for ventilation or forced cooling. Operating temperature range is -25 °C to 70 °C; storage range extends from -40 °C to 80 °C.
Integrated auxiliaries and releases
This variant ships with an undervoltage release (UVR) and two auxiliary switches plus one trip alarm switch (HQ configuration). The UVR ensures the breaker trips if control voltage drops, which is standard for safety circuits and emergency-stop chains. Rated insulation voltage is 800 V, giving headroom for 690 V applications.