The AFDD electronics detect both series arcs (load-side, 1 A to 13 A) and parallel arcs (line-to-line or line-to-neutral, 50 A to 500 A) and trip the internal MCB before an arc fault can sustain a fire.
The 13 A rating is the continuous load it carries in normal service; the B-curve means it trips magnetically at 3 to 5 times rated current (39–65 A) for short circuits, which suits resistive and general-purpose loads like lighting and socket circuits. The 1P+N configuration switches the line conductor and switches the neutral, but the neutral pole is not protected — it's a switched neutral, not a second protected pole. The unit occupies a single width unit (18 mm) on the DIN rail, so it fits standard distribution boards without crowding.