The Siemens 3RV2111-1KA10 is a SIRIUS motor-protective circuit breaker with built-in overload relay function — one unit that covers short-circuit protection and thermal overload in a single DIN-rail footprint. It's designed for motor branch circuits where you need coordinated protection without a separate overload block. At 690 V the SCCR drops to 4 kA, so verify your system voltage against the full curve before committing the BOM line. If you're starting high-inertia loads (centrifuges, large flywheels) that need Class 20 or 30, this isn't the right pick. No ground-fault detection on this variant (confirms none), so if your code requires GFCI on that circuit, you'll need an add-on module or a different frame.
Mounting and integration — fits the standard rail
The 65 mm width is a standard 3-module footprint — it'll sit in any 65 mm-wide slot on the rail without crowding adjacent devices. That means you can butt it against the back panel and the door, and only need breathing room in the vertical plane. The 97 mm depth keeps the front face shallow enough for most 200 mm-deep enclosures. Main contacts use M3 screw terminals, accepting 2× (0.5 to 1.5 mm²) solid or stranded, or 2× (0.75 to 2.5 mm²) — enough for the control wiring on most motor starters up to the breaker's rating. The terminals are screw-type, not spring-cage, so keep a Pozidriv #1 on the van.
Temperature and environment
Operates from -20 °C to +60 °C ambient, and survives storage and transport from -50 °C to +80 °C.