What this MCCB delivers on the line
The Siemens SENTRON 3VA1125-5EF36-0KC0 is a 3-pole molded case circuit breaker (MCCB) rated for 25 A continuous current at 40 °C, with a TM240 thermal-magnetic release that provides both overload and short-circuit protection in a single device. Its interrupting capacity reaches 187 kA at 240 V AC, 121 kA at 415 V, and 75.6 kA at 440 V — figures that give you selectivity headroom in high-fault panels without cascading upstream breakers. The 70 mm depth and 76.2 mm width fit standard SENTRON mounting footprints, so it drops into existing panel layouts with no rework of the busbar or gland plate.
Breaking capacity and thermal derating — the real selection numbers
The 187 kA at 240 V is the headline, but the 121 kA at 415 V and 75.6 kA at 440 V are what matter for most 400 V-class industrial panels. At 690 V the rating drops to 17 kA — still adequate for most motor branch circuits, but verify against your transformer impedance. The thermal derating curve is flat from 40 °C to 50 °C (full 25 A), then steps down: 24 A at 55 °C, 23.5 A at 60 °C, 23 A at 65 °C, and 22.5 A at 70 °C. If your panel ambient runs above 50 °C, size the breaker one frame step higher or accept the reduced ampacity.
Panel integration and auxiliary options
The 3VA1125-5EF36-0KC0 includes a factory-fitted shunt trip (STL) release (order code 3VA9688-0BL33) and two auxiliary switches (HQ type). The shunt trip allows remote tripping from a PLC or emergency-stop circuit — verify the coil voltage matches your control supply. No undervoltage release, no ground-fault monitoring, and no communication module on this variant; those are separate order-code options if your application requires them. Front IP40 protection is standard for clean indoor panels; no washdown rating.