It protects three-phase motors against overload, short circuit, and phase failure — the phase failure detection means a lost phase on the line side trips the breaker, preventing single-phasing damage to the motor windings. For high-inertia loads (fans, flywheels) you would step up to Class 20; this one is sized for pumps, compressors, and conveyors. In a panel with a transformer-fed bus that can deliver 50 kA fault current, this breaker holds coordination without an upstream fuse.
Mounting position is any — vertical, horizontal, or flat on a backplate, no derating needed for orientation. The screw terminals accept 2×(1…2.5 mm²) or 2×(2.5…10 mm²) solid or stranded, with M4 main-contact screws and a Pozidriv size 2 tip.