The Schneider Electric A9K24725 is a miniature circuit-breaker from the Acti9 iK60N series, rated 25 A at 30 °C with a C-curve (magnetic tripping between 5 and 10 times In). It protects a 3P+N circuit — three protected poles plus a switched neutral — on AC networks at 50/60 Hz, with a breaking capacity of 6000 A Icn at 400 V AC per EN/IEC 60898-1. The thermal-magnetic trip unit covers overload (thermal bimetal) and short-circuit (solenoid) in one compact body.
The 3P+N body takes 8 module pitches of 9 mm each — 72 mm wide — so it occupies eight slots on a standard DIN-rail terminal block row. Depth is 78.5 mm, height 85 mm. Tunnel-type terminals accept 1…25 mm² rigid or 1…16 mm² flexible cable; tighten to 2 N·m. Strip 14 mm of insulation. IP20 finger-safe front, suitable for enclosed panels only.
The C-curve (5–10 × In) means the magnetic trip acts between 125 A and 250 A for a 25 A breaker, which suits mixed resistive and moderate inductive loads (lighting, small motors, control transformers). Limitation class 3 per the same standard means it limits the let-through energy in a short-circuit, protecting downstream wiring. Rated insulation voltage is 440 V AC; overvoltage category III suits fixed-installation distribution boards.