The Siemens SENTRON 3VA1112-1AA36-0HA0 is a 3-pole switch disconnector in MCCB design, rated at 125 A continuously across the full operating temperature range from 40 °C to 70 °C — no derating needed. It is built on the 160 A frame and intended for isolation and switching of loads where overload or short-circuit protection is handled upstream or by a separate device. The shunt trip release (STL) accepts 12-30 V DC or 24 V AC 50/60 Hz for remote tripping, making it suitable for emergency-stop circuits or controlled disconnection in a panel.
What the ratings mean for fit
The 125 A rating holds at every temperature point from 40 °C up to 70 °C — no thermal derating curve to calculate, which simplifies panel sizing in warm cabinets. The 690 V AC rated operating voltage covers standard 400 V and 480 V systems with headroom. The 500 V DC rating allows use in some DC bus or battery circuits. The 800 V rated insulation voltage (Ui) defines the internal air and creepage distances; it is the ceiling for the insulation system, not a continuous operating voltage. The 38 W maximum power loss at full load matters for enclosure heat budgeting — a 3-pole device dissipating that much heat in a sealed cabinet may require ventilation or a larger enclosure. The shunt trip release (STL) is the only auxiliary release fitted — there is no undervoltage release, no auxiliary contact block, and no communication function. The trip indicator is absent, so the handle position is the only visual state cue. For applications requiring a remote status signal, an external auxiliary switch block (optional motor drive slot available) must be added. The front terminal connection accepts lug-type conductors, which is the standard for panel feeder circuits.
Integration and mounting
The device measures 130 mm high, 76.2 mm wide, and 70 mm deep — a compact footprint for a 125 A disconnect. The front-terminal lug connection allows straightforward bus-bar or cable landing. The IP40 protection on the front face means it is protected against tools and small wires entering the enclosure, but not against water ingress; it is intended for indoor panel mounting where the cabinet provides the environmental seal. The operating temperature range of -25 °C to 70 °C and storage range of -40 °C to 80 °C cover most industrial environments.