Switch disconnector, 125 A, no overload or short-circuit protection
The Siemens SENTRON 3VA1112-1AA36-0DF0 is a 3-pole switch disconnector on the IEC frame 160, rated at 125 A. It is built without overload or short-circuit protection — it is a disconnect, not a breaker. The clamp connection terminals accept standard copper conductors for panel wiring. The part ships with an undervoltage release rated 208-230 V AC 50/60 Hz, plus one auxiliary switch changeover and one trip alarm switch changeover. The undervoltage release drops the switch open when control voltage falls below its dropout threshold, which is useful for safety interlocks or emergency-stop circuits that need to guarantee isolation on power loss.
Lifecycle and sourcing
For a BOM line that calls out this exact switch disconnector, the part is sourced and quoted to order against an RFQ. Availability and current pricing are confirmed at quote time through independent distribution.
What the ratings mean for fit
The 125 A continuous rating on the IEC frame 160 means this switch handles full-load current for motor circuits or distribution feeders up to that ampacity. Because it provides no overload or short-circuit protection, it must be paired with upstream overcurrent devices — typically a molded-case circuit breaker or fuses sized to protect the downstream conductors and load. The undervoltage release coil is rated 208-230 V AC 50/60 Hz. That is a common control voltage in North American and European panels. If your control transformer or UPS supplies a different voltage, the release will not hold in — verify the coil rating against your control circuit before specifying. The auxiliary switch changeover and trip alarm switch changeover provide dry contacts for status feedback to a PLC or indicator lamp. The changeover (SPDT) contact gives both normally-open and normally-closed signals from a single device, which simplifies wiring when you need both a run status and a fault signal.
Panel integration
Mounts on a DIN rail or panel-mount base within the enclosure. The clamp connection terminals accept solid or stranded copper conductors — strip length and torque values follow the manufacturer's published guidelines for the 125 A rating. The 3-pole footprint occupies a standard width on the DIN rail; leave clearance for the undervoltage release coil wiring and auxiliary contact terminals.