Field Tool
Cable Footage and Slack Estimator
Add up the cable a job needs (route, slack, vertical runs and tails, allowance), compare it with the reel, read the length used from the footage marks, and size slack coils.
Reel covers the required length with 254.5 ft to spare. Required 3,245.5 ft.
Good: Reel covers the required length with 254.5 ft to spare.Required Length
3,245.5 ft
- Route (R)
- 2,700.0 ft
- Slack (S)
- 400.0 ft · 6 loops in 2 slack rows
- Vertical and tails (V)
- 10.0 ft
- Allowance (A)
- 135.5 ft · 5% of route + vertical, planning assumption
- Reel
- 3,500.0 ft
- Remaining on the reel (M)
- 254.5 ft
- Owner reserve
- none set
- Used by the marks
- 3,272.0 ft · 26.5 ft more than required
- Minimum coil diameter
- 12.4 in (1.0 ft)
Minimum diameter for slack at rest. Loops formed while pulling need the pulling radius (20 × OD); see the Pull Planner. At rest: 2 × 10 × OD (TIA-568.3); use the manufacturer’s value if larger.
Where the Numbers Come From
Slack goes where the design shows it, in the length the owner's construction standard specifies: see AE-10 Slack Storage Loops and Snowshoes and UG-11 Cable Placement Underground. To bring in a route you already built, plan it in the Pull Planner and use "Import from Pull Planner".
About the example. Example job, not a design. Slack lengths are one owner's published values (Florida DOT Section 633-3.1.4, July 2015 edition; current text to be verified). The 10 ft pulling-end cut-off is from one Kansas DOT plan sheet. The pull box count, 5% allowance, 3,500 ft reel and footage marks are FAHMY example choices, not standards. Use your owner's specification and your cable's data sheet. The route is the Pull Planner's teaching route: route geometry only, not a design. The Pull Planner's tension result is for its own example cable, so enter this cable's weight there before you use it. Cable inside the boxes counts as part of the stored slack in this example; on a real job, add vertical rows for risers and in-box runs.
Show the Math
R = Σ route lengths S = Σ count × length each (slack rows) V = Σ count × length each (vertical and tail rows) A = (p ÷ 100) × (R + V), or 0 when p is blank L_req = R + S + V + A M = L_reel − L_req L_used = |m_end − m_start| D_coil = 2 × 10 × OD
Symbols
- R: route length, design or measured. S: slack. V: vertical runs and tails.
- p: allowance in percent. A: allowance length. The allowance base leaves out slack, because slack is a specified length, not a measured one.
- L_req: required length. L_reel: reel length from the reel tag. M: left on the reel.
- m_start, m_end: the footage marks printed on the jacket, converted to the selected unit. The absolute value is used because marks count up or down depending on which end leaves the reel. The length used is for information and does not change the status.
- OD: cable outside diameter from the data sheet, in inches (feet mode) or millimetres (metre mode). D_coil is the minimum coil diameter, in the same unit.
Status
- Reel entered and shorter than the required length: critical.
- A slack row without a length, a blank allowance, a vertical or tail row without a length, a blank reel length, less left on the reel than the owner reserve, or nothing to total yet: warning. The tool names each one.
- Also a warning (draft rules pending the owner's review): text in a route, count, length, allowance, reel or reserve field that is not read as a number (it is left out of the totals); a slack, vertical or tail row with a length but no count; or a route total of 0 while slack or vertical runs are entered.
- Otherwise good. A reel exactly equal to the required length is good, not critical.
- Results show one decimal place; the status uses the unrounded values.
Defaults and Where They Come From
- Slack length per location: per owner spec. Enter the owner's value (AE-10, UG-11); there is no national standard. The example shows 100 ft per side of a splice in a splice box and 50 ft per pull box: one owner's published values (Florida DOT Section 633-3.1.4), not a standard.
- Allowance: a planning assumption the owner sets, not a standard value: per owner spec. Blank for a real job until the owner sets it; 0 means none. The example's 5% is a FAHMY example choice. Some published calculators apply such a percentage to a total that includes slack; this tool's base is route + vertical.
- Owner reserve (optional): per owner spec. Blank means none set.
- Reel length: from the reel tag. The example's 3,500 ft reel is a FAHMY example choice.
- Coil diameter: twice the at-rest bend radius of 10 × OD , or the manufacturer's value if larger. It is the minimum diameter for slack at rest (coils and figure-8 loops). Loops formed while pulling need the pulling radius (20 × OD); see the Pull Planner.
- Units: 1 ft = 0.3048 m and 1 in = 25.4 mm , both exact. Switching units converts every entered length; the footage marks stay as printed in their own unit.
Assumptions
- Sweeps add no length in the Pull Planner model, so put the cable inside enclosures in the vertical and tail rows. The import reads only the Pull Planner's straight lengths, and it stops if any straight there is blank or not a valid length, so the route never comes in short.
- The route length is what you designed or measured.
- Footage marks are the manufacturer's printed marks, so their accuracy is the manufacturer's.
- The opening example (proposed from industry research, owner review pending) is an example job, not a design: a 144-fiber loose-tube cable on the Pull Planner's teaching route. Slack lengths are one owner's published values (Florida DOT Section 633-3.1.4); the 10 ft pulling-end cut-off is from one Kansas DOT plan sheet; the 0.62 in OD is from two 144-fiber data sheets. The pull box count, 5% allowance, 3,500 ft reel and footage marks are FAHMY example choices, not standards. While a field holds its example value, its tag reads "Example". Cable inside the boxes counts as part of the stored slack in the example.
Sources
ANSI/TIA-568.3 (bend radius) · unit definitions (1 ft = 0.3048 m and 1 in = 25.4 mm, both exact). Example only, status verify: Florida DOT Standard Specifications Section 633-3.1.4 (slack lengths; confirmed in the July 2015 edition, current text to be verified) · one Kansas DOT ITS plan sheet (pulling-end cut-off).
Planning estimate. Owner specifications and the cable data sheet govern.
FAHMY tools give planning estimates. The owner's specifications, the authority having jurisdiction and the manufacturer's data govern every job. Values marked "Planning assumption", "Planning default", "Typical maximum", "Rule of thumb" or "Example" are editable starting points, not requirements; "Per owner spec" fields take the owner's value.