How is straight-run pulling tension calculated?

Tension = cable weight per unit length × pull length × coefficient of friction. This is the standard basic cable-pulling tension formula for a straight conduit section, per common cable-pulling engineering references such as Southwire's pulling tension guidelines.

What friction coefficient should I use?

A typical PVC-conduit-to-cable-jacket friction coefficient is approximately 0.5, though it varies with conduit material, cable jacket type, and whether pulling lubricant is used.

Does this calculator cover conduit runs with bends?

No — this covers a STRAIGHT run only. Pulls with bends require adding capstan-equation tension multipliers for each bend, and the calculated tension must always be checked against the cable manufacturer's maximum allowable pulling tension (often based on conductor cross-section) before pulling. Consult a qualified installer for multi-bend or long/complex pulls.

Can I use this for a riser or a run that slopes?

No. Weight × length × friction is the level-run form, and it assumes the only thing resisting you is the cable dragging along the bottom of the conduit. On a rise you are also lifting the cable, and that weight arrives as tension whether there is any friction or not. Take the metric defaults — 1.2 kg/m over 50 m at 0.5 friction — and the breakdown line reads 30 kgf. The same cable hanging in a 50 m vertical run holds back its full 60 kgf, double, because at 0.5 friction the level-run form is keeping only half the cable's weight against you. The page cannot tell the two apart: it has no input for rise or fall. Downhill is not the easy case it looks either. Tension falls, but on a steep enough fall the cable can start to run on its own, and that is a pull to be braked rather than one to bring a smaller winch to. Anything off the level is outside what this calculates.

What do I enter for cable weight when more than one cable goes in the conduit?

The combined weight per unit length of everything entering it, not one cable's. The answer is strictly proportional to this field, so 3.6 kg/m for three 1.2 kg/m cables triples the tension. Two traps live in this box. First the quoted unit: cable weight is commonly published per 1,000 ft or per kilometre, and the field wants it per foot or per metre — it takes nothing above 20 kg/m (about 13.4 lb/ft), and anything higher is clamped to that ceiling, with a notice saying so, the moment you leave the field — so the tension you read back belongs to no cable you own. That ceiling catches a mistyped per-kilometre figure, but it also catches a genuinely heavy bundle, and the answer is just as meaningless either way. Second, a bundle is worse than its own arithmetic: cables sharing a conduit ride on one another and against the wall instead of lying flat, and cable-pulling practice multiplies the summed weight by a correction factor greater than one to account for it. This page applies none, so a multi-cable answer from here sits on the optimistic side. The weight already sitting in the field (1.2 kg/m, shown as 0.806 lb/ft in imperial) is a placeholder so the page has something to show — take yours off the drum tag or the data sheet.

Where does this figure stop being enough to pull on?

At the point where the question turns from whether the winch can move the cable into whether the cable survives being moved. Tension is not the only limit on a pull: wherever the cable turns a bend it is pressed against the inner radius of that bend, and the sidewall pressure there can flatten insulation while the total tension still looks comfortable. That is a separate check with a limit of its own, and it cannot be read off this number. Two habits follow on site. Pull the run in whichever direction puts the bends early, because a bend multiplies whatever tension has already built up before it — the same bend costs far more near the winch than near the feed. And keep lubricant going in with the cable instead of tipping a slug down the mouth of the conduit at the start, which coats the first few metres and is wiped off long before the far end. The reason to be strict is that this damage does not announce itself: a conductor stretched by an over-pull, or a jacket scored on a coupling, can terminate, test and go live, then fail months later inside a wall. So treat this number for what it is — a feasibility check before you choose a winch, not the figure you pull to.

Materials & Quantities

Cable Pulling Tension Calculator (Straight Run)

Estimate the pulling tension needed to install cable through a straight conduit run.

Answers as you typeNo submit button
Every formula citedNamed published standards
Calculated in your browserNo account, nothing uploaded

SettingsSettings for this calculationUS

Market

Imperial · sales tax

Cable Weight per Unit Length

The cable's weight per unit length, including its jacket and any armor.

From the cable data sheet, jacket and armour included, because all of it presses on the conduit wall. For a multi-conductor pull enter the combined figure for everything going in at once — three cables pulled together are one load, and the friction that resists them is set by the total. Armoured cable is the case where an assumed figure goes furthest wrong.

Total Pull Length

The total length of the straight conduit run being pulled.

The straight run this estimate applies to. Bends do not add to pulling tension, they MULTIPLY it: each one raises the tension leaving it by a factor over the tension entering it, so tension climbs geometrically through a run and two runs of equal length with different bend counts are not comparable jobs. If the pull has bends, treat this figure as a floor and plan the lubrication and the pull direction around the corners.

Coefficient of Friction (Typically ~0.5 for PVC Conduit)

The friction between the cable jacket and the conduit interior.

A typical PVC-conduit-to-cable-jacket friction coefficient is approximately 0.5; it varies with conduit material, lubricant use, and cable jacket type.

Estimated pulling tension

67 lbf

Low confidence

This covers a STRAIGHT run only — pulls with bends require adding capstan-equation tension multipliers for each bend, and the calculated tension must be checked against the cable manufacturer's maximum allowable pulling tension (often based on conductor cross-section) before pulling. Consult a qualified installer for multi-bend or long/complex pulls.

Tension in kgf: 30.18 kgf

Then change the inputs to see how far the answer moves.

Show calculation logic

How this was calculated

Formula source(s)

Straight-run pulling tension = cable weight per unit length × pull length × coefficient of friction, the standard basic cable-pulling tension formula for a straight conduit section (per common cable-pulling engineering references, e.g. Southwire's pulling tension guidelines); a typical PVC-conduit-to-cable-jacket friction coefficient is approximately 0.5

Inputs used

Cable Weight per Unit Length: 0.81 lb/ft
Total Pull Length: 165 ft
Coefficient of Friction (Typically ~0.5 for PVC Conduit): 0.5

Intermediate steps

Tension in kgf: 30.18 kgf

Final result66.52 lbf

Confidence note: This covers a STRAIGHT run only — pulls with bends require adding capstan-equation tension multipliers for each bend, and the calculated tension must be checked against the cable manufacturer's maximum allowable pulling tension (often based on conductor cross-section) before pulling. Consult a qualified installer for multi-bend or long/complex pulls.

What this calculation does not cover

Jamming and clearance are failure modes that are not forces, so no tension figure predicts them. Three cables of similar diameter can wedge side by side going through a bend when the conduit's inside diameter falls in a narrow band near three times the cable diameter, and the pull locks solid at a tension the winch will happily exceed and the cable will not survive. A single large conductor has the mirror problem — it needs a minimum clearance to the conduit wall through every bend. Check the geometry of what is going in before trusting any number here.
Cold changes the pull and can end it. Jacket and insulation stiffen as the temperature drops, so the same cable in the same conduit pulls appreciably harder in winter than the friction coefficient above suggests, and most cables carry a minimum installation temperature below which the jacket cracks rather than bends. Neither the friction figure nor the weight in this calculation moves with temperature; warming the reel before the pull does more than either of them.
This is what the conduit costs you. The reel adds its own before the cable reaches the conduit at all — a heavy drum with a stiff brake, a feed that is not squared up with the conduit mouth, or a sheave set at the wrong angle each contribute back-tension and an extra effective bend right at the head of the run, and being at the head, everything downstream multiplies it.

Add the equipment this sizes

This result is a specification — 67 lbf — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

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Schematic, drawn to the proportions you entered — not to scale on screen.

Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.1.1

Regulatory standards & verification citations1

Straight-run pulling tension = cable weight per unit length × pull length × coefficient of friction, the standard basic cable-pulling tension formula for a straight conduit section (per common cable-pulling engineering references, e.g. Southwire's pulling tension guidelines); a typical PVC-conduit-to-cable-jacket friction coefficient is approximately 0.5

Cite this page

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Protection this work requires

Stop and check first. Textured ceiling coatings, board behind panels, floor tiles and bitumen adhesive in older buildings — built before asbestos was banned or phased out where you are — can contain asbestos, and drilling or sanding them releases fibres. Do not disturb it — have it sampled first. This is not a job for better PPE.

Tools and safety for this job

To first-fix electrical. Generic types, no brands, no prices.

Assume every cable is live until proved dead at the point you will touch, with a two-pole tester you have just proved on a known source.

First-fix electrical: This site does not publish a tool list for electrical installation work. In every market it serves, fixed wiring is either reserved to a registered electrician or notifiable to a building authority, and the failure mode is a fire or an electrocution months later rather than a visibly bad job on the day. The calculator gives you the quantities to discuss and to buy against. The installation is a job for a qualified electrician, and the certificate they issue is the point of them.

Now that you have the number

These guides cover the work this quantity is for — the first ones run this calculator inside the section that raises the question.

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How to calculate cable pulling tension (straight run) in 4 steps

Cable Weight per Unit LengthThe cable's weight per unit length, including its jacket and any armor.
Total Pull LengthThe total length of the straight conduit run being pulled.
Coefficient of Friction (Typically ~0.5 for PVC Conduit)The friction between the cable jacket and the conduit interior.
Estimated pulling tensionThe tool computes the estimated pulling tension from those figures and shows the formula, its sources, and a confidence rating alongside it.

Estimated pulling tension by cable weight per unit length

Page defaults, not your figures above.

Cable Weight per Unit Length	Estimated pulling tension (lbf)
0.4 lb/ft	32.8
0.6 lb/ft	49.2
0.8 lb/ft	65.6
1 lb/ft	82
1.2 lb/ft	98.4
1.4 lb/ft	115
1.6 lb/ft	131

Frequently asked questions

How is straight-run pulling tension calculated?: Tension = cable weight per unit length × pull length × coefficient of friction. This is the standard basic cable-pulling tension formula for a straight conduit section, per common cable-pulling engineering references such as Southwire's pulling tension guidelines.
What friction coefficient should I use?: A typical PVC-conduit-to-cable-jacket friction coefficient is approximately 0.5, though it varies with conduit material, cable jacket type, and whether pulling lubricant is used.
Does this calculator cover conduit runs with bends?: No — this covers a STRAIGHT run only. Pulls with bends require adding capstan-equation tension multipliers for each bend, and the calculated tension must always be checked against the cable manufacturer's maximum allowable pulling tension (often based on conductor cross-section) before pulling. Consult a qualified installer for multi-bend or long/complex pulls.
Can I use this for a riser or a run that slopes?: No. Weight × length × friction is the level-run form, and it assumes the only thing resisting you is the cable dragging along the bottom of the conduit. On a rise you are also lifting the cable, and that weight arrives as tension whether there is any friction or not. Take the metric defaults — 1.2 kg/m over 50 m at 0.5 friction — and the breakdown line reads 30 kgf. The same cable hanging in a 50 m vertical run holds back its full 60 kgf, double, because at 0.5 friction the level-run form is keeping only half the cable's weight against you. The page cannot tell the two apart: it has no input for rise or fall. Downhill is not the easy case it looks either. Tension falls, but on a steep enough fall the cable can start to run on its own, and that is a pull to be braked rather than one to bring a smaller winch to. Anything off the level is outside what this calculates.
What do I enter for cable weight when more than one cable goes in the conduit?: The combined weight per unit length of everything entering it, not one cable's. The answer is strictly proportional to this field, so 3.6 kg/m for three 1.2 kg/m cables triples the tension. Two traps live in this box. First the quoted unit: cable weight is commonly published per 1,000 ft or per kilometre, and the field wants it per foot or per metre — it takes nothing above 20 kg/m (about 13.4 lb/ft), and anything higher is clamped to that ceiling, with a notice saying so, the moment you leave the field — so the tension you read back belongs to no cable you own. That ceiling catches a mistyped per-kilometre figure, but it also catches a genuinely heavy bundle, and the answer is just as meaningless either way. Second, a bundle is worse than its own arithmetic: cables sharing a conduit ride on one another and against the wall instead of lying flat, and cable-pulling practice multiplies the summed weight by a correction factor greater than one to account for it. This page applies none, so a multi-cable answer from here sits on the optimistic side. The weight already sitting in the field (1.2 kg/m, shown as 0.806 lb/ft in imperial) is a placeholder so the page has something to show — take yours off the drum tag or the data sheet.
Where does this figure stop being enough to pull on?: At the point where the question turns from whether the winch can move the cable into whether the cable survives being moved. Tension is not the only limit on a pull: wherever the cable turns a bend it is pressed against the inner radius of that bend, and the sidewall pressure there can flatten insulation while the total tension still looks comfortable. That is a separate check with a limit of its own, and it cannot be read off this number. Two habits follow on site. Pull the run in whichever direction puts the bends early, because a bend multiplies whatever tension has already built up before it — the same bend costs far more near the winch than near the feed. And keep lubricant going in with the cable instead of tipping a slug down the mouth of the conduit at the start, which coats the first few metres and is wiped off long before the far end. The reason to be strict is that this damage does not announce itself: a conductor stretched by an over-pull, or a jacket scored on a coupling, can terminate, test and go live, then fail months later inside a wall. So treat this number for what it is — a feasibility check before you choose a winch, not the figure you pull to.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.