400 A MCCB with ETU350 — selectivity and SCCR headroom
The Siemens SENTRON 3VA2340-7HN32-0KL0 is a 3-pole molded case circuit breaker rated 400 A continuous, fitted with the ETU350 electronic trip unit. It is designated for line protection and carries a breaking capacity of 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V — figures that define its fault-interruption capability across common distribution voltages. The ETU350 trip unit supports adjustable long-time, short-time, instantaneous, and ground-fault protection curves, making this breaker suitable for selective coordination in a main or feeder position. The 400 A rating holds up to 50 °C ambient; above that it derates linearly to 340 A at 70 °C — a curve to check if the breaker sits in a warm enclosure or near other heat sources.
Integration and mounting
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The breaker mounts on a panel or in an enclosure via the standard SENTRON 3VA footprint. The front face carries an IP40 protection rating — suitable for installation inside a cabinet with a door, not for open-panel washdown environments. Auxiliary contact configuration includes 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch — enough for remote status indication without an add-on module. The base switch variant is 3VA2340-7HN32-0AA0.
Electrical ratings and compliance
Rated insulation voltage Ui is 800 V. Maximum power loss is 96 W. Operating temperature range is -25 °C to 70 °C; storage range -40 °C to 80 °C. The breaker includes a trip indicator and a voltage trigger, but no undervoltage release and no communication module.