Motor protection MCCB with ETU350M — what the ratings mean for fit
The Siemens SENTRON 3VA2140-5MN32-0JA0 is a 3-pole molded case circuit breaker (MCCB) built for motor protection, rated 40 A continuous current (Iu) at up to 50 °C ambient — above that it derates to 38.4 A at 55 °C and 36 A at 70 °C, so if your panel runs hot, that 40 A nameplate shrinks. The ETU350M electronic trip unit gives you adjustable overload and short-circuit protection curves, plus phase failure detection, which matters for three-phase motor loads where losing a phase cooks the winding fast. Interrupting capacity is the headline here: 187 kA at 240 V, 121 kA at 415/440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That 187 kA figure at 240 V is high for a 40 A frame — it means this breaker can sit upstream of a large transformer or in a high-fault industrial service entrance without needing a current-limiting fuse ahead of it. At 690 V the 17 kA still covers most motor branch circuits. It ships with a shunt trip (STL) release built in — part number 3VA9688-0BL32 — for remote or emergency-stop tripping. The base switch is 3VA2140-5MN32-0AA0. No auxiliary contacts, no undervoltage release, no ground-fault module on this variant. If you need those, this isn't the order code.
Panel fit and integration
Dimensions are 105 mm wide, 181 mm high, 86 mm deep — standard SENTRON 3VA2 frame footprint. Rated insulation voltage is 800 V. Maximum power loss is 75 W — that's the heat it dumps into the enclosure at full rated current. If you're packing several of these in a sealed cabinet, factor that into your thermal calculation.
Operating range and storage
Runs from -25 °C to 70 °C ambient during operation. Storage range: -40 °C to 80 °C. Mechanical endurance is 20,000 cycles (latching).