CommScope ConQuest Conduit Construction User Manual
Page 44
Pull Calculations
Maximum pull lengths, pulling tension at the end of a straight section of conduit, pulling tension at the end of a bend,
and sidewall pressure can be calculated quite easily. However, it is important to remember that these calculations are
only estimates. This is due to the significant variances in construction practices and lack of accounting for:
• Undulations, rising, falling, and straightness of the straight sections of conduit
• Cable stiffness
• Lubrication, coefficients of friction, foreign debris in conduit
Calculating A Complete Run
An example provides a clear illustration of how to calculate a complete run and understand the effects of bends on
pulling tensions and sidewall pressure. Calculations have been performed in both directions. In the first calculation, the
run has the reel setup at point ‘A’ with the cable being pulled from point ‘H’. The second calculation is the opposite with
the reel setup at point ‘H’ and the cable being pulled from point ‘A’. The cable used is QR715. The formulas used for
calculating this run are located in the Appendix.
The resulting calculations for this run are:
Pulling from A to H =
64 pounds pulling tension
Pulling from H to A =
54 pounds pulling tension
NOTE: The direction of pull and distances between bends can have a dramatic impact on pulling
tensions.
5.6
Pulling Cable into Conduit
Pull Calculations