Siemens 3VA1125-5EF36-0HC0 — SENTRON 25 A MCCB with TM240 Release
The Siemens 3VA1125-5EF36-0HC0 is a 3-pole SENTRON molded case circuit breaker rated for 25 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. Its 187 kA breaking capacity at 240 VAC makes it a high-interrupting device for fault-current-heavy industrial feeds — think transformer secondaries or main distribution panels where available fault current exceeds what a standard MCB can clear. At 415 VAC it still holds 121 kA, dropping to 75.6 kA at 440 VAC and 17 kA at 690 VAC. The TM240 release is a fixed thermal-magnetic unit — no interchangeable trip block, no electronic adjustment. That means the overload and short-circuit pickup are factory-set to the 25 A frame rating. For applications needing adjustable long-time, short-time, or ground-fault protection, this is not the variant; look to the electronic-release versions in the 3VA family. The trade-off is simplicity and reliability in a fixed-coordination panel.
Thermal Derating and Operating Range
This breaker holds its full 25 A rating from 40 °C through 50 °C ambient. At 55 °C it derates to 24 A, at 60 °C to 23.5 A, at 65 °C to 23 A, and at 70 °C to 22.5 A. The operating ambient range is -25 °C to +70 °C, storage from -40 °C to +80 °C. If this breaker sits in a non-air-conditioned electrical room or a hot panel near drives, use the 50 °C column as the design limit — above that, the continuous current must be reduced per the curve.
Integrated Auxiliary and Shunt Trip
Factory-fitted with 2 auxiliary switches (HQ type) and a shunt trip release (STL) — order code 3VA9688-0BL30 for the integrated auxiliary trip assembly. The shunt trip allows remote tripping from an E-stop circuit or a PLC output, which is standard for safety disconnects in machine-tool and conveyor applications. No undervoltage release, no phase-failure detection, no communication module on this variant.
Dimensions and Panel Fit
Width 76.2 mm (3-inch pitch, standard for 3-pole MCCBs in the SENTRON frame), height 130 mm, depth 70 mm. IP40 on the front — protected against tools and wires >1 mm, but not against water ingress. Mounts on a DIN rail or direct panel; the 76.2 mm width matches the footprint of other 3VA1 frame breakers, so swapping from a lower-rated unit (e.g., a 16 A version) requires no busbar or enclosure modification.