Switch disconnector, not a breaker — what that means on the line
The Siemens SENTRON 3VA1112-1AA32-0AD0 is a 3-pole switch disconnector in an MCCB-style housing, rated for 125 A continuous current (Iu) at up to 690 V AC or 500 V DC. It is designed for isolation and switching duty, not overcurrent protection — the description explicitly states 'without overload protection, without short-circuit protection'. This matters for BOM fit: if your panel relies on the device for branch-circuit protection, this is the wrong part; if you need a load-break disconnect with visible isolation and auxiliary signaling, it is exactly right. The 125 A rating covers the IEC frame 160 footprint, so it handles motor loads, resistive heating banks, or transformer primaries up to that current. The 690 V AC rating covers 400 V line-to-line systems with headroom; the 500 V DC rating suits battery banks or DC bus applications within that voltage ceiling.
Physical fit and auxiliary wiring
The front-terminal busbar connection means incoming and outgoing conductors land on the front face. Three auxiliary switches (HQ type, 3 CO contacts) are built in. The part accepts an optional motor drive for remote switching, and the auxiliary release slot is unused on this variant (no undervoltage or shunt trip fitted).
Maximum power loss is 38 W at full rated current.