The Siemens 3VA1112-1AA36-0JH0 is a SENTRON switch disconnector in a 3-pole MCCB-style frame, rated for 125 A continuous current (Iu) with a 160 A frame size. It provides no overcurrent or short-circuit protection — it is a pure isolating and switching device, sized for load-break duty on feeders or downstream of a protective device. The front-terminal clamp connection accepts up to 17 x 6.5 mm busbar or cable lugs, matching the standard panel layout for 3VA frame-160 breakers.
Shunt trip and auxiliary contact fit
This variant ships with a factory-fitted shunt trip (STL) rated 110–127 V DC / AC 50/60 Hz, plus two auxiliary switches (HQ) and one trip alarm switch (HQ). That means it can be remotely tripped from a PLC or emergency-stop circuit without a separate undervoltage release — the STL fires on applied voltage, not on loss of power. The auxiliary contact set gives three CO contacts for status feedback to a control system or panel lamp. The same frame accepts a motor-drive option for remote motorized operation, though that is not included here.
Physical integration
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width is three 25.4 mm module slots — standard for a 3-pole MCCB footprint on a DIN rail or panel-mount plate. Front terminal access keeps wiring accessible without removing the device. IP40 front protection means it is suited for enclosed panel use, not open washdown areas.
Electrical ratings in context
Rated insulation voltage Ui is 800 V; maximum operational voltage is 690 V AC 50/60 Hz and 500 V DC. Short-time withstand current is 2 kA for 0.5 s and 1 s — this is the current the device can carry momentarily during a fault without welding contacts, not a breaking capacity. The switch disconnector is not designed to interrupt fault currents; it isolates the load after upstream protection has cleared the fault. Operating temperature range is -25 °C to +70 °C, storage from -40 °C to +80 °C. Maximum power loss at rated current is 38 W.