The Schneider Electric A9N21380 is a ProDis DT40N miniature circuit breaker (MCB) sized for distribution boards. Rated 40 A with a D trip curve, it is built for loads with high inrush — motor starters, small transformers, or lighting ballasts — where the magnetic trip fires between 10 and 14 times the rated current (400 to 560 A instantaneously). The thermal-magnetic trip unit handles the overload side.
Breaking capacity and dual standard certification
This breaker carries dual certification to EN/IEC 60898-1 and EN/IEC 60947-2. Under the domestic-standard 60898-1, the rated breaking capacity (Icn) is 6000 A at 230 V AC. Under the industrial-standard 60947-2, the ultimate breaking capacity (Icu) is 10 kA at 230...240 V AC. That dual rating means the same unit can go into a residential DB (6 kA is enough for most domestic service entrances) or a light-industrial sub-distribution board where fault levels are higher. Overvoltage category IV and pollution degree 3 confirm it is rated for the mains entry point, not just downstream sub-circuits.
Termination and environment
The housing is IP20 finger-safe once installed. Limitation class 3 per 60898-1 limits let-through energy, which helps downstream selectivity with smaller MCBs.