What the ratings mean for your panel
The Siemens SENTRON 3VA1112-6EF36-0HH0 is a 3-pole molded case circuit breaker (MCCB) rated 125 A continuous at 40 °C, with a breaking capacity of 220 kA at 240 V AC and 154 kA at 415 V AC — high enough to handle fault currents in large distribution boards or as a main breaker in a transformer-fed panel. The 125 A frame holds up to 125 A from 40 °C through 50 °C, then derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C; if your enclosure runs hot, you need to account for that curve. It is designed for line protection — meaning it protects the feeder cable, not a motor or a specific load — and includes a shunt trip (STL) for remote opening and a set of 2 auxiliary switches plus 1 trip alarm switch (HQ) for status feedback to a PLC or SCADA.
Integration notes for the panel builder
The 3VA1112-6EF36-0HH0 measures 70 mm deep, 76.2 mm wide, and 130 mm tall — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures. The shunt trip (STL) and auxiliary switch block (2 aux + 1 trip alarm) are factory-installed, so no field wiring of add-on modules is needed. Power loss at full load is 28.1 W — factor that into your enclosure thermal calculation if you are packing multiple breakers in a sealed cabinet.