What this MCCB carries and where it fits
The Siemens SENTRON 3VA1040-3ED32-0HH0 is a 3-pole molded case circuit breaker rated 40 A continuous at 40 °C, with an interrupting capacity of 75.6 kA at 240 V and 52.5 kA at 415 V. Those are the numbers that decide whether it clears a fault before the upstream device blows — at 440 V it still holds 32 kA, and at 500 V or 690 V it drops to 7.5 kA, so the voltage at the fault point matters for coordination studies. Rated insulation voltage is 800 V, so it's built for 690 V line-to-line systems with margin. Power loss at full load runs 10.8 W — not a panel-heating concern in a standard enclosure, but worth a glance if you're packing multiple breakers in a sealed box. The design is line protection (not motor or generator protection), so the trip curve and accessories are optimized for feeder and distribution duty. It ships with a shunt trip release and carries 2 auxiliary switches plus a separate trip alarm switch — enough status feedback for a PLC input module without adding a stack-on block.
Thermal derating — the real-world current
The 40 A rating holds from 40 °C through 50 °C ambient. At 55 °C it derates to 38.4 A, at 60 °C to 37.6 A, at 65 °C to 36.8 A, and at 70 °C to 36 A. If the panel ambient runs above 50 °C, size the breaker one frame up or accept the reduced continuous current. The operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Panel fit and integration
The 3VA1040-3ED32-0HH0 measures 130 mm high, 76.2 mm wide, and 70 mm deep. It mounts on a DIN rail or directly to a backplate via the molded-case footprint. The 3-pole width (76.2 mm) is standard for this frame size — it occupies the same slot as other 3VA1040 variants, so a panel laid out for the 3VA1110-5ED36-0AC0 will accept this breaker without drilling new holes or moving the bus bars.