The Siemens 3VA1112-6EF32-0HA0 is a 3-pole SENTRON molded case circuit breaker rated 125 A at 40 °C, with a TM240 thermal-magnetic trip unit and an integrated shunt trip release. Its interrupting capacity hits 220 kA at 240 V, 154 kA at 415 V, and 75.6 kA at 440 V — numbers that tell you this breaker is built for high-fault panels where the available short-circuit current is substantial.
Sizing the trip and the shunt trip
The TM240 thermal-magnetic trip is fixed at 125 A continuous at 40 °C. As ambient climbs, the thermal element derates: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, 114 A at 70 °C. That matters if the breaker lives inside a hot enclosure — size the load at the lower end of the curve, not the nameplate.
At 130 mm tall, 76.2 mm wide, and 70 mm deep, the breaker occupies three standard 25 mm DIN-rail modules. The shunt trip terminals are clearly marked on the accessory cover; wire them with 1.5 mm² stranded for the control circuit.