If one phase drops on a three-phase motor, the breaker will trip — prevents single-phasing damage that cooks windings.
Any mounting position is acceptable. Clearance requirements: 50 mm upwards and downwards, 30 mm at the sides, zero forwards and backwards. That's the breathing room for arc flash venting and cable bending — don't cram it tighter in a gland plate layout. Main circuit connection uses ring cable lug, screw size M3. Wire it with the right lug for your cable cross-section — don't wrap bare wire around the terminal.
Temperature compensation is active across the operating range — the thermal trip curve stays accurate even if the panel ambient drifts. That matters in a cement plant control room that hits 50 °C in summer; this breaker eats the dust and runs.