K-curve 4 A — inductive-load branch protection
The ABB 2CDS271337R0337 is a 1-pole miniature circuit breaker with K tripping characteristics, rated 4 A continuous current and 440 V rated insulation voltage. The K curve means the magnetic trip threshold sits at 8–12× In — designed to ride through the inrush of transformers, solenoid valves, and motor starters without nuisance tripping on the magnetizing surge. Rated short-circuit breaking capacity Icn is 11.2 kA per the standard, with an ultimate Icu of 15 kA — the breaker clears a fault up to that level without welding the contacts, then remains serviceable. Overvoltage category III rating confirms it is rated for fixed-installation downstream of the service entrance, not just outlet-level protection.
DIN-rail footprint and panel integration
Snaps onto standard 35 mm DIN rail per EN 60715. The 17.5 mm width (1 module) and 69 mm depth fit a single-pole position in any distribution board or control panel — no extra clearance needed beyond the standard busbar comb spacing. Height is 111 mm, matching the ABB S200 series envelope. IP20 on the front face (finger-safe terminals with the breaker in the ON position), IP40 on the sides (tool-proof against wire probes). The bi-directional cylinder-lift terminal accepts both copper and aluminium conductors up to the rated cross-section; tightening torque max 2.8 Nm ensures the connection holds through thermal cycling.