The Siemens SENTRON 3VA2340-7HN32-0AE0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C. It carries a 330 kA interrupting capacity at 240 VAC, stepping down to 242 kA at 415/440 VAC and 187 kA at 500 VAC — numbers that tell you this breaker is sized for high-fault service-entrance or main-tie applications where upstream coordination matters. The interrupting rating at 690 VAC drops to 7.5 kA, so if you're feeding a 690 V bus, confirm the available fault current stays under that threshold. This is a line-protection design (no undervoltage release, no ground-fault monitoring, no communication function built in). The auxiliary switch package is a 4-switch HQ configuration, and the basic switch supplied is order code 3VA2340-7HN32-0AA0. It's a straightforward main breaker — no frills, no hidden surprises, just a high-interrupting 400 A frame.
Thermal derating and panel fit
The 400 A rating holds steady up to 50 °C. Above that, it derates: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel runs hot — say, a packed enclosure near a furnace line — you'll want to factor that into the load schedule. The operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. Physical footprint: 248 mm tall, 138 mm wide, 110 mm deep. That depth is worth checking if you're swapping into an existing panel that was dimensioned around a different MCCB frame — the 110 mm depth is shallower than some older 400 A frames, so it may free up wire-bend space or require a different mounting adapter. Width and height are standard for this class.
Power loss at full rated current is 96 W maximum — a useful number for enclosure thermal calculations if you're stacking multiple breakers in a single panel. The breaker is designed for line protection; it's not a motor-protective device (no ground-fault, no undervoltage trip), so pair it with a separate motor protection relay if that's your load type.