What the ratings mean for fit
The Siemens 3VA2140-7HL42-0AA0 is a SENTRON molded case circuit breaker (MCCB) sized for line protection in distribution panels. Its continuous current rating holds flat at 40 A from 40 °C all the way to 70 °C — no derating curve to chase across the ambient range of a warm enclosure. That thermal stability is unusual for a compact MCCB and simplifies panel build when the breaker sits near other heat sources. The interrupting capacity tells the selectivity story: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.7 kA at 690 V. At typical 400 V class distribution voltages, the 242 kA figure gives substantial headroom for high-fault utility feeds or transformer secondaries. The sharp drop at 690 V (3.7 kA) means this is not a 690 V main — it is a 400 V class device with a 690 V withstand rating for isolation duty only. The ETU320 electronic trip unit provides adjustable overload and short-circuit protection curves, configurable for coordination with downstream breakers. Four poles handle three-phase plus neutral, or two independent circuits in a single enclosure. The IP40 front protection suits indoor panel mounting; no additional gasketing is needed for clean, dry environments.
Panel integration notes
The 3VA2140-7HL42-0AA0 measures 140 mm wide by 181 mm tall by 86 mm deep. That 86 mm depth is the dimension that matters for gland-plate clearance and door swing — it is shallower than many 4-pole MCCBs in the 40 A class, which helps in tight backpanels. Mounts on a standard DIN rail or with rear-panel screws; the SENTRON family uses a common footprint across the 3VA2 range, so a panel laid out for a 63 A frame accepts this 40 A unit without re-drilling.