The Siemens SENTRON 3VA1112-1AA42-0JC0 is a 4-pole switch disconnector in the 3VA1 IEC frame 160 platform, rated for a continuous current Iu of 125 A. It is designed for isolation and switching duty without overload or short-circuit protection — a pure disconnect function. The shunt trip (STL) release operates on 110-127 V DC or AC 50/60 Hz, and the unit carries two integrated auxiliary switches HQ for status feedback. Front terminals accept busbar connections, and the front face is IP40 rated. Panel depth is 70 mm, width 101.6 mm, height 130 mm.
Key Ratings and What They Mean
Rated continuous current Iu of 125 A means this disconnect can carry 125 A continuously without exceeding temperature rise limits — sized for a 125 A feeder or branch circuit where the load current stays at or below that value. Rated insulation voltage Ui of 800 V AC and maximum operational voltage 690 V AC / 600 V DC cover standard 400 V and 480 V distribution systems with headroom. The short-time withstand ratings of 2 kA for 1 s and 0.5 s (Limited To 1 S / Limited To 0.5 S) define the fault current the disconnect can survive without damage during the upstream breaker's clearing time — coordination with the upstream protective device is required.
Deployment Context
This is a panel-mount disconnect for distribution boards or motor control centers. The front terminals and busbar connection simplify bus-stack assembly in a SENTRON distribution panel. The two auxiliary switches HQ provide remote status indication — useful for PLC or SCADA monitoring of the disconnect position. The IP40 front face suits indoor panel environments; no outdoor or washdown rating. The shunt trip allows remote emergency-off or interlock tripping, common in safety circuits or load-shedding schemes.