Cable Reel Capacity / Length on Reel
How many feet of a given cable fit on a reel (or how much is left on a partial reel).
Example
You enter
- Reel flange diameter (in) 30
- Drum / hub diameter (in) 12
- Inside width between flanges (in) 18
- Cable outside diameter (in) 1
- Winding fill factor 0.9
You get
- Cable that fits on the reel 802 ft
Details, formula, and sources
length = fill x pi x (flange^2 - drum^2) x traverse / (48 x cable_OD^2), lengths in inches. A 30 in flange, 12 in drum, 18 in wide reel holds ~801 ft of 1 in cable; a fatter 1.5 in cable drops it to 356 ft, since the cable OD enters squared. The figure that tells the crew whether the pull is on one reel or two.
length_ft = fill_factor x PI x (flange_dia_in^2 - drum_dia_in^2) x traverse_width_in / (48 x cable_od_in^2).
Reel-capacity identity by name (annular winding volume / cable cross-section, with a fill factor); first-principles geometry.
The reel-capacity geometry is public first-principles; the reel dimensions come from the reel and the cable OD from the cable.
Estimate. AHJ and licensed professional govern.
Field names used by the API: flange_dia_in, drum_dia_in, traverse_width_in, cable_od_in, fill_factor, length_ft
- Fill factor ~0.85-0.9 for imperfect winding; the winding pattern governswinding practice
- Cable OD the cable outside diameter; it enters squared, so a fatter cable cuts the reel sharplycable manufacturer