The Siemens SENTRON 3VA1140-4EF32-0DC0 is a 3-pole molded case circuit breaker (MCCB) rated 40 A at 40 °C, built for line protection. It carries a 121 kA breaking capacity at 240 V AC, stepping down to 75.6 kA at 415 V and 52.5 kA at 440 V — numbers that tell you this breaker handles high-fault panels without cascading upstream. An integrated undervoltage release (UVR) means it can drop the load on loss of control power, which is what you want on a safety-critical feeder or a motor control center.
What the ratings mean for your panel
The 40 A rating holds flat from 40 °C to 50 °C — no derating in a warm enclosure — then eases to 39 A at 55–60 °C and 37 A at 70 °C. That thermal curve matters when you're packing breakers side-by-side in a switchboard. The 121 kA at 240 V is the headline interrupting rating; the 75.6 kA at 415 V is what you coordinate against downstream devices in a 400 V distribution board. Insulation voltage is rated 800 V, so this MCCB is comfortable in 690 V systems.
Panel fit and integration
Footprint: 76.2 mm wide (3 in), 130 mm tall (5.12 in), 70 mm deep (2.76 in). That width is a standard 3-pole MCCB slice on a DIN rail or panel-mount base. It ships with two auxiliary switches (HQ design) and the undervoltage release pre-integrated — no extra wiring for the UVR coil if you're already running a control voltage. Power loss maxes at 13.3 W, so heat buildup in a dense lineup is manageable.