The C-curve means it holds through motor inrush and capacitor charging without nuisance trips — typical for general-purpose lighting and socket circuits. The 3 kA breaking capacity (IEC 60947-2) is the hard ceiling: if the panel's prospective short-circuit current exceeds that, this breaker won't clear the fault safely. Stick to residential or small commercial sub-distribution where the utility transformer is sized for it. At 70 A on a 3-pole frame, each pole dissipates 6.3 W in hot state — that's noticeable in a crowded enclosure. Plan for ventilation or derating if other devices are packed tight.
Three modular-width units (54 mm wide) snap onto standard DIN rail. Mount in any position;