What this MCCB is and what it does
The Siemens 3VA1040-3ED32-0AE0 is a SENTRON molded case circuit breaker (MCCB) sized for line protection duty — the panel's main feeder or a large branch, not motor-starting. It's a 3-pole unit rated 40 A continuous at 40 °C, with a TM210 thermal-magnetic release that handles overload and short-circuit trip curves in one package. No undervoltage release, no ground-fault monitoring, no communication module: this is the plain-vanilla, fast-moving version that keeps a BOM simple.
Breaking capacity — what it actually interrupts
Breaking capacity drops with system voltage, as expected. At 240 V it clears 75.6 kA; at 415 V it's 52.5 kA; at 440 V it's 32 kA; at 500 V and 690 V it holds at 7.5 kA. That 7.5 kA at 690 V is the number to check if you're feeding a 690 V drive bus — the upstream fuse or breaker needs to coordinate so the MCCB sees a fault within its rating. Rated insulation voltage is 800 V, so the 690 V application is within the dielectric design.
Thermal derating and panel fit
The 40 A rating holds from 40 °C up to 50 °C. Above that it derates: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, 36 A at 70 °C. If your enclosure hits 60 °C near the top, you lose about 2.4 A — plan the load accordingly. The case is 76.2 mm wide, 130 mm tall, 70 mm deep; it mounts on a DIN rail or panel-mount plate. Power loss at full load is 10.8 W, which matters for thermal rise in a sealed enclosure.