The Siemens 3VA2140-5KP32-0AA0 is a 3-pole SENTRON molded case circuit breaker (MCCB) configured for line protection, carrying a full-rated 40 A continuously from 40 °C through 70 °C — no derating needed across the typical panel ambient range. That 40 A is the same at 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, and 70 °C, so the breaker holds its rating in a warm enclosure without a temperature correction factor. The interrupting capacity tells the selectivity story: 187 kA at 240 V, 121 kA at 415 V and 440 V, 76 kA at 500 V, and 3.8 kA at 690 V. At typical 480Y/277 V distribution, the 121 kA SCCR gives ample headroom for a high-fault service entrance or downstream coordination with smaller branch breakers. The ETU850 electronic trip unit (adjustable Ii from 60 A to 480 A, Ig min 0.5 s) enables precise long-time and short-time pickup settings — critical for selective coordination studies required by NEC 240.87 and 240.91.
Communication function is built in (no external module required), and the neutral conductor is upgradeable or retrofittable — useful for 4-wire systems where you add the neutral pole later.