The Siemens 3VA1340-6EF32-0AA0 is a SENTRON molded case circuit breaker (MCCB) built for line protection — three-pole, rated 400 A continuous at 40 °C, with a TM240 thermal-magnetic overcurrent release. In a panel with high available fault current — say, near a large distribution transformer — that rating gives you selectivity headroom so a downstream fault clears without taking the whole board out.
Thermal derating — the real-world current you can pull
At 40 °C you get the full 400 A. That holds flat through 50 °C. At 55 °C it derates to 392 A, at 60 °C to 384 A, at 65 °C to 376 A, and at 70 °C to 367 A. If your panel ambient runs hot — inside a non-climate-controlled enclosure in a steel mill or foundry — the 55 °C and 60 °C figures are the ones to size against, not the 40 °C sticker.
The interrupting rating drops as voltage climbs: 220 kA at 240 V, 154 kA at 415 V and 440 V, 121 kA at 500 V, and 17 kA at 690 V. That 17 kA at 690 V is the number to check if you're feeding a 690 V drive or motor circuit — it's still adequate for most industrial installations, but verify your available fault current at the point of installation.
Dimensions: 248 mm high, 138 mm wide, 110 mm deep. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.