Cable Pulling Calculator | Kewo Engineering

Start from a template

Loads a typical cable, conduit and route. Every input can then be changed.

Cable

Type Number of cables Cable

Construction Insulation Conductor Size Circuit Number of conductors Equipment ground Assembly Assemblies in the conduit Size Cables in the conduit

Library Voltage class Insulation level Conductor Size Construction Insulation Neutral / shield Cables in the conduit

Drag to turn. Double-click to reset.

Cable details

Weight per cablelb/ft Aluminum temper Minimum bend radiusin

Conduit

Type Trade size Inside diameterin

Pull

Lubrication Coefficient of friction Configuration, 3 cables Weight correction factor Feed tension Feed tension, enteredlb Pulling device Eye ratinglb Grip ratinglb

More settings

Sidewall pressure limit Limit enteredlb/ft Horizontal bends Maximum tension, enteredlb Sheaves in the vaults

Count the ground conductor in the allowable tension

Route

From A (start) to B (end). The pull is checked in both directions.

Report details

Location Prepared by Reference

Pull

Route

Pull Color Vertical Labels

Drag to rotate, right-drag to pan, scroll to zoom. Click the route to find a segment.

Tension along the route

Segments

Cable in the conduit

Friction and limits

Pull A to B

Pull B to A

Inputs

Basis

Pulling tension by the equations of IEEE 1185 and the Southwire Power Cable Installation Guide (2005): straight and inclined sections, horizontal bends (exact equation with the cable weight, or T e^(μφ)) and vertical bends at any angle, with the effective coefficient of friction μ′ = w μ. In vertical bends the cable follows the wall it bears on: the outside wall at low tension, the inside wall otherwise. Tension does not go below zero. Where a vertical bend turns downhill at low tension the tension can be highest inside the bend; the maximum tension and the sidewall pressure of each bend use the highest tension along it, not only the tensions at its ends.

Weight correction factor, clearance, jam ratio and sidewall pressure for one, two, three (cradled or triangular) and four cables; 1.4 for more. Allowable tension from the conductor stress (Southwire Table 4, 80 % for more than three conductors), the pulling device and the rated tension of communications cable. Each result is checked by a 3D numerical integration of the same path.

At a vault end the cable path in the vault is included: fed from the reel at grade down into the duct, over sheaves (no friction when they turn freely) or through a feeder tube (the conduit friction), and pulled out around a sheave at the duct mouth, up to the opening or out over a second sheave to grade. The weight of the cable lowered or lifted in the vault changes the tension, and each sheave is checked for sidewall pressure on its radius (Southwire E-20) and against the cable minimum bending radius.