25 A MCCB with 187 kA interrupting capacity — line protection for high-fault panels
The Siemens SENTRON 3VA1125-5EF36-0AD0 is a 3-pole molded case circuit breaker rated for 25 A continuous at 40 °C ambient, using a TM240 thermal-magnetic release. It carries a 187 kA interrupting capacity at 240 V, stepping down to 121 kA at 415 V and 75.6 kA at 440 V, with 17 kA available at both 500 V and 690 V. That SCCR headroom means it handles high-fault utility feeds without cascading upstream — sized for main or feeder duty in industrial switchboards. Rated insulation voltage is 800 V, and maximum power loss sits at 8.5 W. The breaker includes three auxiliary switches (HQ design) for status feedback to a PLC or annunciator panel. No undervoltage release, no ground-fault monitoring, no communication module — this is a straight thermal-magnetic line-protection device, not a smart breaker.
Thermal derating and panel integration
The 25 A rating holds flat from 40 °C through 50 °C, then derates to 24 A at 55–60 °C and 23 A at 65–70 °C. If the panel ambient runs above 50 °C, factor that 1 A drop per 5 °C step into the load schedule. Dimensions are 70 mm deep, 76.2 mm wide, and 130 mm tall — standard 3-pole MCCB footprint for DIN-rail or mounting-plate installation. The 8.5 W dissipation per unit adds up in a multi-breaker enclosure; check the panel thermal budget if you are packing several in a row.