What this part is and what it does
The Siemens SENTRON 3VA1112-1AA36-0AD0 is a 3-pole switch disconnector in an MCCB frame. It is rated for 125 A continuous current and handles up to 690 V AC or 500 V DC.
What the ratings mean for fit
The 125 A continuous rating sets the maximum uninterrupted current the switch can carry without exceeding its thermal limits. The 690 V AC rated operational voltage covers standard 400 V three-phase systems with headroom for 480 V or 600 V industrial supplies. The 500 V DC rating makes it usable in DC bus or battery bank isolation applications within that voltage ceiling. Three auxiliary switches HQ (changeover contacts) are built in, giving you three CO contact sets for status feedback to a PLC or panel indication without needing a separate auxiliary block. The front terminal connection with clamp-type terminals accepts standard lug or cable terminations for the main circuit. The IP40 rating on the front means it is protected against solid objects over 1 mm (tools, wires) but not sealed against water ingress — suitable for indoor panel mounting where splash risk is absent. The operating temperature range of -25 °C to 70 °C covers most conditioned industrial enclosures.
Where it fits in the panel
The 3VA1 frame measures 70 mm deep, 76.2 mm wide, and 130 mm tall — a compact footprint that fits standard MCCB mounting positions in a distribution board or control panel. The front terminal arrangement keeps wiring accessible from the front, and the optional motor drive (listed as a product extension) allows remote switching if needed later.