What it is and what it does
The Siemens SENTRON 3VA2010-5KQ42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 100 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. That flat thermal curve is unusual for an MCCB; most competitors start knocking current back at 50 °C. The ETU860 electronic trip unit gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves, plus a communication function for remote monitoring or integration into a plant-wide power management system. The interrupting ratings are tiered by system voltage: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3 kA at 690 V. That 187 kA figure at 240 V means it handles fault currents up to the highest practical levels on a 240 V distribution bus — useful for large transformer secondaries or high-capacity UPS outputs.
Panel fit and mounting
Dimensions are 181 mm high, 140 mm wide, 86 mm deep. That 86 mm depth is the critical number for shallow enclosures or gland-plate clearance — it's the dimension that runs into the back of the panel. The 140 mm width for a 4-pole frame is standard for this class; verify your existing busbar or lug spacing if you're swapping from a different manufacturer. IP40 on the front means it's protected against tools and wires over 1 mm, but not sealed against water ingress — keep it inside a rated enclosure for washdown environments.