What this 3VA2340-7HN32-0KC0 is and what it does
The Siemens SENTRON 3VA2340-7HN32-0KC0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, designed for line protection in distribution panels. Its interrupting capacity hits 330 kA at 240 V AC, tapering to 242 kA at 415 V and 7.5 kA at 690 V — so at typical 400 V class supply voltages it clears faults well into the high-fault-current range without cascading upstream breakers. The unit ships with a factory-installed shunt trip release and two HQ auxiliary switches, making it ready for remote trip and status feedback without additional wiring modifications.
Sizing and thermal derating
The 400 A rating holds flat from 40 °C through 50 °C. Above that it derates linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, 340 A at 70 °C. If the panel ambient runs toward the upper end of that range, the continuous load must be trimmed accordingly — the breaker itself is rated for operation up to 70 °C ambient. Maximum power loss is 96 W, which factors into enclosure ventilation sizing.
Physical fit in the panel
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That depth includes the breaker body; the shunt trip and auxiliary switches add no extra projection beyond the standard 3VA2340 form factor. The 138 mm width is the same as other 3-pole 3VA frames in this current class, so a panel laid out for a 400 A SENTRON MCCB accepts this unit without re-drilling the mounting plate or re-routing bus bars.
What the built-in accessories mean for the circuit
The shunt trip (STL) release allows a remote signal — from an emergency-stop button, a fire-alarm relay, or a PLC digital output — to open the breaker independently of the overcurrent trip mechanism. The two HQ auxiliary switches provide form-C contacts that mirror the main contact position, so a control system knows whether the breaker is open or closed. No undervoltage release is fitted on this variant; if undervoltage protection is needed, the 3VA family offers a separate UVR module that plugs into the same accessory slot.