The A9P42716 is a Schneider Electric Acti9 iC40 miniature circuit breaker rated 16 A with a B curve, 3P+N poles, and a breaking capacity of 4500 A Icn at 400 V AC per EN/IEC 60898-1 and 6 kA Icu at 400 V AC per EN/IEC 60947-2. The B curve (3 to 5 x In magnetic trip per EN/IEC 60898-1, 4 x In ±20% per EN/IEC 60947-2) means it trips fast on moderate overloads — typical for lighting and general-purpose circuits where inrush isn't severe.
The B curve's magnetic trip range (3 to 5 x In) means it holds short-duration surges up to about 80 A before the magnetic element reacts — fine for resistive and most electronic loads, but not for motor starting where a C or D curve would be needed. Breaking capacity: 4.5 kA Icn (service breaking capacity per EN/IEC 60898-1) is the standard for domestic distribution; the 6 kA Icu (ultimate breaking capacity per EN/IEC 60947-2) is higher and covers industrial fault levels. The part carries dual certification to both standards, so it can be specified in either a household consumer unit (60898-1) or an industrial sub-distribution board (60947-2). Thermal-magnetic trip technology combines a bimetal strip for overload protection (slow, heat-dependent) and a solenoid for short-circuit protection (instantaneous above the magnetic threshold).
Mounts on DIN rail via clip-on. Width is 54 mm (6 x 9 mm pitches). Depth 74 mm, height 85 mm. Tunnel terminals top and bottom accept 1 to 16 mm² rigid or 1 to 10 mm² flexible; wire strip length 14 mm; tightening torque 2 N·m. Neutral position is left. IP20 on the body, IP40 in a modular enclosure — fine for dry indoor panels; not rated for washdown. Earth-leakage protection requires a separate block (not integrated).