What it is and what it does
The Siemens 3VA2140-5HN36-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 40 A continuous current across its full ambient temperature range from 40 °C to 70 °C — no derating needed up to that ceiling. That's a solid 40 A at 70 °C, which means this breaker holds its rating in a hot panel where others might step down. It's a 3-pole unit designed for line protection, fitted with an ETU350 electronic trip unit. The interrupting ratings are substantial: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That 187 kA at 240 V tells you this is built for high-fault-current industrial services — think transformer secondaries or large motor control centers where the available fault current is high.
Panel fit and mounting
Dimensions are 105 mm wide, 181 mm tall, and 86 mm deep. That 105 mm width is a standard 3-pole MCCB footprint — it'll drop into most panel layouts without re-drilling the mounting plate. The IP40 front protection means it's fine for a dry indoor enclosure; no special gasketing needed for the front face. No undervoltage release, no communication module, no ground-fault monitoring on this variant — it's a straight line-protection breaker. If you need those functions, you'd look at a different suffix in the 3VA2 family.