The Siemens 3VA1112-1AA42-0DA0 is a SENTRON 3VA1 switch disconnector in an IEC frame 160 package, rated for 125 A continuous current (Iu) across 4 poles. It is configured as a pure disconnect — no overload or short-circuit protection elements onboard — making it a load-break switch for isolation duty rather than a circuit breaker. The 125 A rating means it handles the full load current of a 4-pole distribution or motor feeder circuit where overcurrent protection is provided upstream or by a separate device.
Undervoltage release and connection details
This variant ships with an undervoltage release (UVR) rated 208-230 V AC 50/60 Hz. The UVR trips the disconnector when the control voltage drops below its dropout threshold — standard practice for preventing automatic restart after a supply dip on machinery or conveyors where unexpected re-energisation creates a personnel hazard. The main circuit connects via busbar terminals on the front face, so panel layout expects a busbar stack rather than individual cable lugs. No auxiliary contacts are fitted; if status feedback to a PLC is required, the optional auxiliary contact block must be added separately.
Physical fit and environmental limits
Dimensions are 70 mm deep, 101.6 mm wide, and 130 mm high. Front-face protection is IP40.
What the ratings mean for the buyer
The 125 A continuous current rating (Iu) at 800 V insulation voltage (Ui) defines the maximum uninterrupted current the disconnector can carry.