25 A MCCB for line protection — TM240 release, 3-pole
The Siemens SENTRON 3VA1125-3EF36-0AA0 is a 3-pole molded case circuit breaker rated 25 A at 40 °C, designed for line protection in distribution panels. The TM240 thermal-magnetic release provides fixed overload and short-circuit protection without adjustable trip settings — a straightforward fit for standard feeder circuits where coordination studies have already set the pickup. Breaking capacity reaches 75.6 kA at 240 V, stepping down to 52.5 kA at 415 V and 32 kA at 440 V. At 500 V and 690 V it holds 11.9 kA. These numbers cover most industrial service-entrance and sub-distribution scenarios; the 75.6 kA at 240 V is the figure to check against the available fault current at the panelboard. Rated insulation voltage is 800 V, and the front face carries IP40 protection — suitable for enclosed panel mounting where the breaker is not exposed to washdown or dust ingress. The 70 mm depth and 76.2 mm width fit standard SENTRON mounting footprints.
Current derating and thermal limits
The 25 A rating holds steady from 40 °C through 50 °C. At 55 °C it derates to 24 A, and at 70 °C it reaches 23 A. Operating ambient range is -25 °C to 70 °C; storage range extends from -40 °C to 80 °C. Maximum power loss is 8.5 W, which factors into enclosure thermal calculations when grouping multiple breakers.