Line protection MCCB with ETU350 — what the interrupting ratings mean for your panel
The Siemens 3VA2140-5HN32-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection, carrying a continuous current rating of 40 A across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. That 40 A holds at every temperature step (–), so a warm panel enclosure won't force a larger frame than the load requires. The interrupting capacity tells you where this breaker can safely clear a fault without upstream devices having to trip. At 240 V it handles 187 kA; at 415 V and 440 V it's rated 121 kA; at 500 V it drops to 75.6 kA; at 690 V it's 3.7 kA. For a 480 V panel fed by a transformer with high available fault current, the 75.6 kA at 500 V gives headroom — you're not forced into a current-limiting fuse or a larger frame just to meet the SCCR sticker. It uses the ETU350 electronic trip unit, which means adjustable thermal-magnetic curves via a rotary dial — not a fixed bimetal. That matters when coordinating with downstream breakers on a motor branch or a lighting panel: you can shape the trip to avoid nuisance trips on inrush while still clearing a hard short fast.
Mounting and integration — panel fit
Dimensions are 181 mm high, 105 mm wide, 86 mm deep. That 105 mm width is a standard 3-pole MCCB footprint for a 40 A frame — fits existing SENTRON 3VA panel cutouts and busbar risers without adapter plates. IP40 on the front means it's protected against tools and wires >1 mm, which is typical for a dead-front switchboard; no washdown rating, so keep it indoors or in a weatherproof enclosure.
Environmental and compliance notes
Operating range is -25 °C to 70 °C; storage from -40 °C to 80 °C. Maximum power loss at rated current is 1.6 W — negligible for thermal budgeting inside a panel. Insulation voltage rated 800 V. No undervoltage release, no ground-fault monitoring, no communication module on this variant.