What the ratings mean for fit
The Siemens 3VA2340-5KP32-0HH0 is a SENTRON molded case circuit breaker (MCCB) rated for a continuous current Iu of 400 A, meaning it handles that load continuously without tripping under normal conditions — the key figure for sizing the main feeder in a distribution panel or as an incoming breaker on a switchboard. Breaking capacity is the real selector: 187 kA at 240 V AC tells you this breaker can safely interrupt a fault current up to that level without welding contacts or venting arc gas into the enclosure — essential when the available fault current at the service entrance is high. At 415 V and 440 V it still holds 121 kA, and at 690 V it drops to 17 kA, so the voltage class of your system decides which rating governs the installation. The thermal derating curve matters for panel placement: the breaker holds its full 400 A up to 50 °C ambient, then steps down to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel runs hot — say near a drive stack or in a non-ventilated cabinet — you need to apply that derating or upsize the frame. The ETU850 electronic trip unit provides adjustable protection curves (LSI or LSIG depending on configuration), and the shunt trip (STL) design allows remote tripping via a control signal — useful for emergency-stop circuits or supervisory shutdown. The auxiliary contact block carries 2 auxiliary switches plus 1 trip alarm switch (HQ version), giving the PLC or BMS a positive indication of breaker state and fault events.
Sourcing and lifecycle reality
Maximum power loss is 96 W at rated current — that is heat that must be dissipated inside the enclosure. When laying out a panel with multiple 400 A frames, factor that into your thermal budget and ventilation sizing.
Panel integration and mounting
Dimensions are 248 mm high, 138 mm wide, 110 mm deep — a standard MCCB footprint that fits most distribution panelboards and switchboard cubicles. The 3-pole construction with line protection version (not feeder protection) means it is intended for the incoming mains position or a large subfeed, not a motor branch circuit. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. That covers most indoor industrial environments and unheated warehouses; if the breaker sits in a refrigerated space or near a furnace, the lower and upper limits still hold. The communication function and other measurement function indicate this variant supports optional communication modules for remote monitoring and energy metering — useful for a facility looking to integrate breaker data into a building management or SCADA system without adding separate current transformers.