What the ratings mean for fit
The Siemens 3VA1340-5EF32-0AA0 is a SENTRON molded case circuit breaker rated for 400 A continuous current at 40 °C, with a TM240 thermal-magnetic overcurrent release designed for line protection — meaning it protects cables and busbars, not motor loads. The 400 A rating holds steady through 50 °C; above that, it derates to 392 A at 55 °C, 384 A at 60 °C, 376 A at 65 °C, and 367 A at 70 °C, so a warm enclosure or high-ambient panel needs that curve checked against the actual load. Interrupting capacity is the headline here: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 11.9 kA at 690 V. That 187 kA at 240 V is exceptionally high — it handles fault currents from large transformers or utility feeds without needing a current-limiting fuse upstream. At 690 V the 11.9 kA figure is still respectable for a 400 A frame, but verify the available fault current at that voltage.
Panel integration
The 3-pole breaker measures 110 mm deep, 138 mm wide, and 248 mm tall — a standard SENTRON 3VA frame footprint. It mounts directly on a DIN rail or via screw-mount lugs in a distribution panel. No undervoltage release, no shunt trip, no communication module on this variant; it is a straight line-protection device with a TM240 trip unit.