Schneider Electric A9P64320 Acti9 iC40N MCB, 20 A, 3P, D Cur

The A9P64320: The D curve (magnetic trip at 10–14 × In per 60898-1, or 12 × In ±20 % per 60947-2) is sized for loads with high inrush — think motor starters, transformers, or capacitor banks. At 20 A, the instantaneous trip threshold sits roughly between 200 A and 280 A, so it rides through the start-up surge of a small motor or a lighting ballast bank without nuisance tripping. The thermal-magnetic trip unit handles overloads on the thermal side and short-circuits on the magnetic side; there is no electronic adjustment, so what you order is what coordinates. The 54 mm width (6 × 9 mm pitches) is the standard three-pole footprint — no surprises on the DIN rail.