The Siemens 3VA2140-6KP42-0AA0 is a SENTRON molded case circuit breaker rated for 40 A continuous current (Iu) across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. Four poles, line protection version, with the ETU850 electronic trip unit. Breaking capacity hits 242 kA at 240 V AC, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 3.8 kA at 690 V. That 242 kA figure at 240 V means it handles the highest available fault currents on a 240 V secondary without upstream coordination worries — it's sized for the worst-case short-circuit at the main distribution board. Communication function is built in — the ETU850 supports data exchange for power monitoring and trip-event logging. Power loss maxes at 1.6 W, negligible for panel thermal budgeting.
Dimensions are 181 mm high, 140 mm wide, 86 mm deep. The 140 mm width is a standard 4-pole MCCB footprint — it drops into the same mounting cutout as other SENTRON 3VA2 4-pole frames. Operating temperature range is -40 °C to 70 °C, storage from -40 °C to 80 °C — fine for unheated electrical rooms or outdoor cabinets with heaters.