The Siemens SENTRON 3VA1112-4EF36-0DH0 is a 3-pole molded case circuit breaker rated for 125 A continuous current, built for line protection in distribution panels. It carries a TM240 thermal-magnetic release — that's the fixed-trip version, not adjustable — so what you see on the nameplate is what you get for overload and short-circuit protection. The interrupting ratings are substantial: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V, which means it can handle serious fault currents on the secondary side of a transformer or a large motor branch circuit without upstream coordination headaches.
What the ratings mean for your panel
At 76.2 mm wide, 130 mm tall, and 70 mm deep, this MCCB fits the standard SENTRON 3VA footprint — it'll drop into a panel that was laid out for a 3VA1 frame without rewiring the bus bars. The rated insulation voltage Ui is 800 V, so it's comfortable on 480 V or 600 V systems with margin. Operating temperature spans -25 °C to 70 °C, with full 125 A current up to 50 °C; above that it derates to 112.5 A at 70 °C. That matters if this breaker lives near a hot transformer or in a non-climate-controlled enclosure out in the plant.
Auxiliaries and releases
This unit ships with an undervoltage release (UVR) built in — part of the order code's suffix — so it'll trip if control voltage drops. The auxiliary contact block is a 2 auxiliary switches + 1 trip alarm switch HQ configuration, which gives you two form-C contacts for status feedback and a separate alarm contact that changes state only on a fault trip. That's handy for a PLC input that needs to distinguish a manual open from a trip. A trip indicator on the front tells you at a glance whether the breaker opened on overload or short circuit.