The following recommendations are based on a study sponsored by ICEA and can be modified with experience and if more information is known:
A. Maximum Pulling Tension on Cable
- With pulling eye attached to copper conductors, the maximum pulling strain in pounds should not exceed .008 times CMA.
- With pulling eye attached to aluminum conductors, the maximum pulling strain in pounds should not exceed 0.006 times CMA. (Tm = 0.008 x N x CM)
Where: Tm = max. tension, lb.
CM = cir-mil area of each conductor
- With cable grip over non-leaded cable, the maximum pulling strain should not exceed 1,000 lbs. and may not exceed the maximum tension based on 0.008 or 0.006 x total conductor area.
B. Maximum Permissible Pulling Length (Lm = Tu/CW)
Where: Lm = pulling length, feet (straight section)
Tm = maximum tension, lb.
W = weight of cable per foot, lb.
C = coefficient of friction (usually 0.5)
C. Pulling tension must not exceed the smaller of these values:
- Allowable tensions on the conductor
- Allowable tensions on pulling device
- Allowable sidewall pressure
Pulling Eye: T (Cu) = Number of Conductors x circular mils x .008
Basket-Group: T = 1000 lbs. per grip
Sidewall Pressure: p = 300 lbs. x radius of curve in feet