The Class 10 trip characteristic ensures it holds through transformer magnetizing inrush without nuisance tripping, while phase failure detection catches a lost phase on the primary before the transformer saturates and draws damaging current.
The 45 mm width takes one standard modular slot — no side clearance needed. Conductor range accepts 2x (1 … 2.5 mm²) solid or stranded, and 2x (2.5 … 6 mm²) for heavier tails. Mounting position is any, which helps when you're packing a tight enclosure.
The 0.32 A continuous rating is the steady-state current it carries without tripping; for a transformer, that's the primary full-load current. The Class 10 trip allows up to 10 seconds at 600% of rated current before tripping, which is enough to ride through transformer inrush (typically 8–12× FLA for 0.1 s). Power dissipation at rated current is 5.5 W total, 1.8 W per pole, so plan for that heat in a sealed enclosure.