The Siemens 3VA1112-3GE46-0AA0 is a SENTRON molded case circuit breaker rated for 125 A continuous at 40 °C, with a TM220 thermal-magnetic overcurrent release — the thermal element handles overloads, the magnetic element handles short-circuits, and the 220 designation means the magnetic pickup is fixed at 10× In (1250 A). Breaking capacity is what decides whether this breaker clears a fault without welding its contacts or cascading upstream: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V.
The 125 A rating holds flat through 50 °C ambient; above that it derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. If the breaker sits inside a crowded enclosure with poor airflow, use the 70 °C figure for your continuous load calculation — 114 A is the real limit, not the catalog 125 A. Dimensions are 130 mm height, 101.6 mm width, 70 mm depth — a standard 4-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures. Power loss is 28.1 W maximum.