What this MCCB is and what it does
The Siemens SENTRON 3VA2340-5KP32-0AH0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current of 400 A at 40 °C, with an ETU850 electronic trip unit configured for line protection. It carries a rated insulation voltage of 800 V and delivers interrupting capacities of 187 kA at 240 V, 121 kA at 415 V, 121 kA at 440 V, 75.6 kA at 500 V, and 17 kA at 690 V — so it can clear high-fault currents across a range of common industrial voltage levels without upstream coordination issues. The 400 A rating holds flat through 50 °C, then derates to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C; that thermal curve matters when the breaker lives in a warm enclosure or near other heat sources. The ETU850 trip unit provides adjustable long-time, short-time, instantaneous, and ground-fault protection curves, plus a communication function for integration into a plant monitoring system. Auxiliary contacts include 2 auxiliary switches and 1 trip alarm switch (HQ version), giving status feedback for PLC inputs or remote annunciation.
Mounting and panel integration
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. It mounts into a panel or enclosure with the standard SENTRON 3VA footprint — the 138 mm width is a 3-pole frame size that fits the same bus-bar and mounting-hole pattern as other 3VA2 breakers. Front-side IP40 protection means it is suitable for general indoor panel use but not washdown environments. The supplied basic switch is order code 3VA2340-5KP32-0AA0, so the trip unit and switch assembly are matched from the factory.
What the ETU850 trip unit gives you
The ETU850 is an electronic trip unit with communication capability — it can report trip events, current measurements, and breaker status over a fieldbus or to a central monitoring system. It includes a trip indicator (mechanical flag) for local fault identification. There is no undervoltage release, no phase-failure detection, and no ground-fault monitoring built into this variant; those functions would require an external module or a different order code. The maximum power loss at rated current is 96 W, which should be factored into enclosure thermal calculations.