IEEE Std 525 Maximum allowable pulling tension

The maximum allowable pulling tension is the minimum value of Tmax from the applicable following guidelines, unless otherwise indicated by the cable manufacturer. The maximum tension on an individual conductor should not exceed

T(cond) = K× A

where

T(cond) is the maximum allowable pulling tension on individual conductor, in newtons (pounds)
A is the cross-sectional area of each conductor in square millimeters (mm2) (kcmil)
K equals 70 N/mm2 (8 lb/kcmil) for annealed copper and hard aluminum
K equals 52.5 N/mm2 (6 lb/kcmil) for 3/4 hard aluminum

When pulling together two or three conductors of equal size, the pulling tension should not exceed twice themaximum tension of an individual conductor, i.e.,

T(max)  =2  × T(cond)

When pulling more than three conductors of equal size together, the pulling tension should not exceed 60% of the maximum tension of an individual conductor, times the number of conductors ("N"), i.e.,

T(max)= 0.6 × N ×  T(cond)

When pulling using a pulling eye, the maximum tension for a single-conductor cable should not exceed 22.2 kN (5000 lb), and the maximum tension for two or more conductors should not exceed 26.7 kN (6000 lb). The cable manufacturer should be consulted when tensions exceeding these limits are expected. When pulling by basket grip over a nonleaded jacketed cable, the pulling tension should not exceed 4.45 kN (1000 lb). When using a basket-weave type pulling grip applied over a lead-sheathed cable, the force should not exceed 6.67 kN (1500 lb) as determined by the following formula:


T (max) = K(m) x  pi x t ( D – t )

t is the lead sheath thickness, in millimeters (inches)
D is the OD of lead sheath, in millimeters (inches)
K(m) is the maximum allowable pulling stress in MPa (10.34 MPa to 1.38 MPa [1500 to 200 psi] depending on the lead alloy)