D-curve selectivity at 0.5 A — a niche fit for transformer and motor-start protection
The Schneider Electric A9F08370 is an Acti9 iC60H miniature circuit breaker with a D tripping curve, rated 0.5 A and 3-pole (3P). The D curve means magnetic tripping occurs at 12 x In (±20 %), so it tolerates the high inrush of small transformers, solenoid valves, or motor starters without nuisance trips — but the 0.5 A rating limits it to very low-current loads. The part is dual-rated to EN/IEC 60898-1 and 60947-2, so it qualifies as both a branch-circuit protective device and an isolation switch (marked suitable for isolation per both standards).
Mounting and integration — DIN-rail footprint with double terminals
Occupies 6 x 9 mm pitches (54 mm wide), 91 mm tall, 78.5 mm deep — fits a standard distribution board cutout. Double terminals top and bottom accept 1…25 mm² rigid or 1…16 mm² flexible; strip length 14 mm, tightening torque 2 N.m. IP20 finger-safe terminals. Pollution degree 3 rated, overvoltage category IV, so it's suited for main distribution panels in industrial environments, not just final subcircuits.