This paper presents the design and analytical assessment of a universal retractable cord reel that accepts a user-supplied, plug-terminated outdoor cord and contains no internal conductive path. The cord is anchored at its midpoint on a rotating drum so that both ends pay out together, avoiding cord twisting; a flat spiral spring provides retraction, and a 6-tooth ratchet with a hold-to-release lever locks the extended length. The concept was selected with a weighted decision matrix, modelled in SolidWorks. The checks showed that the baseline spring (maximum 0.48 N at the cord) cannot retract a 15.24 m cord. A constraint-based parametric resizing (drum radius 50 mm, winding width 80 mm, 0.36 × 25 × 6400 mm AISI 301 spring with five preload turns) satisfies the capacity, 10 N ergonomic, and fatigue requirements analytically. The thermal model indicates that a fully wound 1.31 mm² cord must be derated to about 2.6–3.4 A.