The Schneider Electric A9N21379 is a DT40N thermal-magnetic miniature circuit breaker from the Prodis range, rated 32 A with a D tripping curve (magnetic trip between 10 and 14 x In). It is a 1P+N unit — one protected pole plus a switched neutral on the left — and clips onto a DIN rail for panel mounting. The breaker is dual-rated to EN/IEC 60898-1 (6 kA Icn at 230 V AC) and IEC 60947-2 (10 kA Icu at 230…240 V AC), so it can serve both residential-distribution and light-industrial feeder circuits.
The 32 A continuous rating (In) sets the maximum steady load this MCB can carry without tripping. The D curve's 10–14 x In magnetic threshold means it will hold through a motor starting surge of roughly 320–448 A for a few cycles before the thermal element takes over — that's the key spec for motor or transformer branch circuits. The dual breaking capacity matters for coordination: 6 kA Icn is the standard for household panels under EN 60898-1, while 10 kA Icu under IEC 60947-2 gives the headroom needed for industrial panelboards where fault currents can be higher. Pollution degree 3 (conforming to IEC 60947-2) means the breaker is rated for the conductive-dust and humidity conditions typical of control cabinets, not just clean indoor residential use.
Tunnel terminals accept flexible cable 0.33…10 mm² or rigid 0.75…16 mm² upstream and downstream. The neutral position is on the left, and the toggle provides local ON/OFF indication. IP20 finger-safe terminals are standard for enclosed panels.