The Schneider A9N21609 is a Clario iDPN N miniature circuit breaker rated 25 A with a D tripping curve and a 6000 A Icn breaking capacity at 400 V AC (50/60 Hz) per EN/IEC 60898-1. The 3P+N configuration protects three poles plus switched neutral, with the neutral on the left side of the DIN-rail clip-on housing (54 mm wide, 81 mm high, 78 mm deep).
The D curve (magnetic trip 10–14 × In) is the key selector: it allows short inrush currents typical of motor-starting or transformer loads without nuisance tripping. At 25 A, this MCB handles sustained loads up to 25 A and will hold through the 250–350 A peak of a motor start before clearing a hard fault.
Panel integration
Tunnel-type terminals accept 0.75–16 mm² rigid or 0.33–10 mm² flexible conductors; tightening torque is 2 N·m. IP20 finger-safe terminals suit enclosed distribution boards. Tropicalisation class 2 per IEC 60068-1 and pollution degree 3 per IEC 60947-1 mean it tolerates humidity up to 95% at 55 °C and conductive dust typical of industrial panels.