What it is and what it does
The Siemens 3VM1125-3EE32-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. Three-pole construction with a TM220 thermal-magnetic overcurrent release — the thermal element handles overloads, the magnetic element clears short-circuits. Rated 25 A continuous at 40 °C, and the breaking capacity hits 76 kA at 240 V AC, 53 kA at 415 V, 32 kA at 440 V, and 12 kA at 500 V. That voltage-dependent interrupting range means you need to match it to the available fault current at your system voltage — at 415 V it still clears 53 kA, which covers most industrial secondary distribution.
Thermal derating and panel fit
The 25 A rating holds flat from 40 °C to 50 °C, then drops to 24 A at 55–60 °C, and 23 A at 65–70 °C. If the breaker sits in a warm enclosure — say next to contactors or a drive — factor that derating into your load calculation. Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep; IP40 on the front face keeps dust out of the mechanism in a clean panel environment. Max power loss is 9 W, negligible for enclosure heat budgeting.