The Siemens 3VA1112-1AA32-0AG0 is a SENTRON switch disconnector in a molded-case circuit breaker (MCCB) footprint — 3-pole, rated 125 A continuous across the full ambient range from 40 °C to 70 °C without any derating. That flat thermal curve means you can mount it in a warm panel next to other heat sources and still count on the full 125 A. It is a disconnect-only device: no overload protection, no short-circuit protection, no undervoltage release. The job is isolating a load under load (it switches off under load, but does not trip on fault).
Ratings that matter for the panel
Rated insulation voltage 800 V, operating voltage 690 V AC and 500 V DC — covers common 400/480 VAC three-phase and 500 VDC battery or solar strings. Mechanical service life is 15 000 operating cycles, typical for a disconnect handle in a panel that sees daily switching. Depth is 70 mm, width 76.2 mm, height 130 mm; it fits the standard SENTRON 3VA frame-160 cutout.