The Schneider Electric A9N21588 is a 3-pole iDPN N miniature circuit-breaker from the Clario range, rated 20 A with a D tripping curve and a breaking capacity of 6000 A Icn at 400 V AC 50/60 Hz, compliant with EN/IEC 60898-1.
Depth of 78 mm and height of 81 mm keep it within the envelope of a typical Clario consumer unit or sub-distribution panel.
The 20 A rated current is the continuous load the breaker carries without tripping under standard conditions. The D-curve with magnetic trip at 10–14 x In means the instantaneous trip threshold is 200–280 A, which avoids nuisance tripping on motor starting or capacitive loads. The thermal-magnetic trip unit provides both overload protection (thermal bimetal) and short-circuit protection (magnetic solenoid). Suitability for isolation is confirmed, and the ON/OFF indication gives local status at a glance.