What this MCCB is and where it fits
The Siemens SENTRON 3VA1112-4EF36-0AA0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a TM240 thermal-magnetic overcurrent release — the thermal element handles overloads, the magnetic element clears short-circuits — and is rated 125 A continuously at 40 °C ambient. That 125 A holds flat through 50 °C, then derates to 114 A at 70 °C, so you can run it near full rating in a warm enclosure without oversizing. The 800 V rated insulation voltage (Ui) means it's comfortable on 480 V and 600 V class systems with margin to spare.
Breaking capacity — what the voltages tell you
Breaking capacity is the core selection parameter for an MCCB, and this one delivers 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. Those figures are symmetrical short-circuit ratings — the current the breaker can safely interrupt at each voltage level. On a 480 V panel with a 65 kA available fault current, this breaker has headroom. On a 690 V drive input, the 11.9 kA rating is the limit to coordinate against. The 3VA series uses current-limiting technology to reduce let-through energy, which helps with downstream component protection.
Physical fit and panel integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep. That 3-inch (76.2 mm) width is the standard 3-pole MCCB footprint for the SENTRON 3VA platform — it occupies three 25 mm modular spaces on a DIN rail or mounts directly to a backplate. The IP40 front-face protection means it is splash-proof from the front but not sealed; install it inside a rated enclosure. Maximum power dissipation is 28.1 W at full load, so factor that into enclosure thermal calculations.