Low-Voltage Cable Footage and Box Count
Cable footage and pull-box count for a drop count.
Example
You enter
- Number of cable drops 48
- Average run length (ft) 120
- Service-loop / dressing slack per drop (ft) 15
- Cable box / spool length (ft) 1000
You get
- Total cable footage 6480 ft
- Cable boxes to order 7
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
Scopetotal = drops x (average run + slack); boxes = ceil(drops / whole runs per box), because a run cannot be spliced. 48 drops at a 120 ft average run plus 15 ft of slack is 6,480 ft - 7 thousand-foot boxes; a denser 100-drop job at a shorter 90 ft run is 10,500 ft but 12 boxes, since only nine 105 ft runs come out of each 1,000 ft box. The slack covers service loops and rack dressing; each run's length is limited separately by the structured-cabling channel limit. Cable is bought by the box.
Formula or tabletotal_ft = drops x (avg_run_ft + slack_ft); runs_per_box = floor(box_ft / (avg_run_ft + slack_ft)); boxes = ceil(drops / runs_per_box) -- each run whole from one box, since TIA-568 allows no splice in a horizontal copper run.
Source and editionLow-voltage cable footage takeoff identity by name (drops x per-drop length; boxes from whole runs per box); first-principles count arithmetic.
Free accessThe footage takeoff is public quantity arithmetic; the drop count and runs come from the drop schedule and the plan.
What governsEstimate. AHJ and licensed professional govern.
API field namesdrops, avg_run_ft, slack_ft, box_ft, total_ft, boxes
- Per-drop length average run plus service-loop/dressing slack (~15 ft); the drop schedule governsdrop schedule / plan
- Channel limit each run is length-limited separately by TIA-568 (the 100 m channel), checked by structured-cabling-channelTIA-568