Siemens 3VA1112-3GF42-0AA0 — SENTRON MCCB, 125 A, 4-Pole
The Siemens 3VA1112-3GF42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 125 A continuous current, built on a 4-pole frame for three-phase plus neutral line protection. Per the datasheet, interrupting capacity reaches 75.6 kA at 240 V, 52.5 kA at 415 V, and 32 kA at 440 V — these figures govern the available fault current the breaker can safely clear without upstream cascade. The TM240 thermal-magnetic release provides fixed overload and short-circuit protection, with no undervoltage release or ground-fault monitoring on this variant. Current derating is documented across the operating range: the breaker carries its full 125 A from 40 °C through 50 °C, then steps down to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. For a panel builder, that means the 50 °C threshold is the practical limit for nameplate rating — above that, the load must be reduced per the thermal curve. Maximum power loss is 28.1 W, which factors into enclosure thermal calculations. Physical dimensions are 130 mm height, 101.6 mm width, and 70 mm depth. The front face carries IP40 protection, suitable for general indoor panel environments where tools or fingers are the primary concern. Rated insulation voltage is 800 V, with operating temperature range from -25 °C to 70 °C and storage from -40 °C to 80 °C.
Integration and Mounting
This MCCB mounts on a DIN rail or panel-mount plate within a standard enclosure. The 4-pole form factor occupies roughly 102 mm of rail width — plan for that footprint plus side clearance for busbar connections and cable bending radius. No communication function or auxiliary voltage trigger is fitted on this base variant; if remote signaling is needed, the 3VA family accepts plug-in accessory modules (shunt trip, auxiliary contacts) that slot into the breaker side.