Motor protection MCCB with ETU350M — what the ratings mean for fit
The Siemens 3VA2110-5MN36-0AF0 is a 3-pole SENTRON molded case circuit breaker (MCCB) built for motor protection, fitted with an ETU350M electronic trip unit. The ETU350M gives you adjustable overload and short-circuit protection curves specific to motor starting inrush — not the same as a thermal-magnetic breaker sized for a resistive load. It also includes phase failure detection, so if one leg drops on a three-phase motor, the breaker trips before single-phasing cooks the winding. Rated continuous current Iu is 100 A, and the thermal derating is published: it holds 100 A from 40 °C through 50 °C, then drops to 96 A at 55 °C, 94 A at 60 °C, 92 A at 65 °C, and 90 A at 70 °C. If your panel ambient runs hot — say, 55 °C inside a non-ventilated enclosure next to a drive — you need to account for that 4 A drop. The breaker itself dissipates up to 75 W at full load, so that heat contributes to the internal ambient. Breaking capacity is the headline number that decides whether this breaker holds on a high-fault bus. At 240 V it's rated 187 kA; at 415 V and 440 V it's 121 kA; at 500 V it drops to 75.6 kA; at 690 V it's 17 kA. If your transformer secondary can push 100 kA at 480 V, this breaker covers it. But if you're on a 690 V mining or marine distribution, the 17 kA limit means you need to verify the available fault current at that voltage — it's not a universal high-interrupting device.
Panel fit and auxiliary wiring
Footprint is 105 mm wide, 181 mm tall, 86 mm deep — standard 3-pole MCCB form factor for a 100 A frame. Mounts on a DIN rail or direct panel; the depth leaves room behind the door for the rotary handle mechanism if you're using one. The auxiliary contact block is factory-fitted as 1 auxiliary switch plus 1 trip alarm switch (HQ configuration), so you get a status signal for the PLC and a separate alarm contact that closes only on a trip event — handy for differentiating a manual open from a fault. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. If this goes into a refrigerated warehouse or an outdoor cabinet in a northern climate, the cold-end spec is fine. The 80 °C storage max means it can sit in a hot shipping container without damage.