What it is and what it does
The Siemens 3VA1112-3EF36-0DH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in three-phase distribution panels. It carries a continuous rating of 125 A at 40 °C, meaning it handles that load continuously without tripping — the rating that governs the main feeder or large branch circuit it protects. Rated interrupting capacity hits 75.6 kA at 240 V, 52.5 kA at 415 V, and 32 kA at 440 V — figures that tell you it can clear a bolted fault at those levels without welding contacts or rupturing the case. That's the number a panel builder uses to verify the breaker matches the available fault current at the installation point. This is a 3-pole unit, so it switches all three phases simultaneously. The design is line protection — no ground-fault monitoring or communication module built in, just a straight thermal-magnetic trip for overcurrent and short-circuit events.
Deployment context and integration
Dimensions are 130 mm height, 76.2 mm width, and 70 mm depth. The undervoltage release (UVR) is built in — it trips the breaker when supply voltage drops below a threshold, which is common on safety circuits or emergency-stop chains where a loss of control power must open the main feeder. The trip indicator gives visual confirmation of a fault trip versus a manual off, which speeds troubleshooting on a down line. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. That covers most indoor industrial environments, including unheated warehouses in cold climates, as long as the breaker isn't expected to close or carry current below -25 °C.