What this MCB does on the rail
The A9N21570 is a 32 A, D-curve miniature circuit breaker from Schneider Electric's Clario iDPN N range, built to EN/IEC 60898-1. It protects a single pole plus neutral (1P+N) in a 18 mm wide clip-on housing that snaps onto DIN rail — no tools needed for mounting, just a screwdriver for the tunnel terminals. The D-curve magnetic trip triggers at 10 to 14 times rated current (320 to 448 A peak), so it's sized for loads with high inrush — think small motors, transformers, or capacitive supplies where a C-curve would nuisance-trip on startup. The thermal-magnetic element handles the overload side, the magnetic coil handles the short-circuit hit. Breaking capacity is 6 kA at 230 V AC, 50/60 Hz, per EN/IEC 60898-1. If your panel's SCCR exceeds 6 kA, you'll want to step up to a higher-rated breaker or add a current-limiting upstream device.
Mounting and wiring — what to expect at the panel
Clip-on mounting to DIN rail, neutral on the left. That's enough for a 32 A feed with standard building wire. IP20 rated — fine inside an enclosure, not for wet or dusty locations. The toggle gives local ON/OFF indication, and the isolation suitability (marked Yes) means it can serve as a disconnection point for the downstream circuit during maintenance, provided the supply is off.