What the 400 A rating and interrupting capacity mean on site
The 3VA2340-5KP32-0AF0 is a SENTRON molded case circuit breaker rated for 400 A continuous current at 40 °C, meaning it can carry a full 400 A load without derating in a typical 40 °C panel ambient. The ETU850 electronic trip unit handles the protection curve, and the breaker includes a communication function — so this isn't a dumb thermal-magnetic breaker; it can talk to a BMS or SCADA for trip events and load monitoring. At 96 W max power loss, this breaker dumps some heat into the enclosure. In a sealed stainless panel on a hot production floor, that 96 W needs to be factored into the thermal budget — don't crowd it next to drives or transformers without ventilation.
Sizing and derating — the real-world current curve
At 55 °C it derates to 375 A, at 60 °C to 350 A, at 65 °C to 325 A, and at 70 °C to 300 A. If your panel ambient runs 55 °C or higher — common in a packed MCC room or outdoor cabinet in summer — the breaker still handles 375 A continuous, but you lose 25 A per 5 °C step. Plan the load accordingly; don't assume 400 A is available at every ambient.
The 3VA2340-5KP32-0AF0 measures 138 mm wide, 248 mm tall, and 110 mm deep. It is a 3-pole MCCB for screw-mounting in a distribution panel.