Screw-type terminals on the main circuit accept 2x (1 to 2.5 mm²) solid or stranded, or 2x (2.5 to 6 mm²) — the same range for both, so no derating when switching between fine-stranded with ferrules and solid. Zero clearance needed at the sides or back; the 45 mm wide footprint leaves room for a contactor alongside in a standard motor starter stack.
The 5 A continuous rating at 690 V maximum sets the motor FLA it can protect — size it to the motor nameplate, not the breaker's maximum. The 100,000-cycle mechanical endurance is the rated life of the main contacts under normal switching — expect fewer cycles if it's used as a disconnect under load regularly.