Appendix > Cable Pulling Calculations > Pulling Tensions 
Version: 10.1 
Given the amount of tension on cables going into a section of conduit (T_{1}), the following equations determine the amount of tension on cables coming out of the conduit section (T_{2}).
Note: T_{1} of the conduit's first section only is the reelback or initial tension.
In subsequent sections of conduit, T, of a preceding section of conduit is T_{1} of the next section of conduit.
T_{2} = Outgoing tension (lb)
T_{1} = Incoming tension (lb)
L = Length of conduit section (ft)
K = Effective coefficient of friction (dimensionless)
W = Total weight of cables (lb/ft)
T = Offset angle (degrees)
e = Base of natural logs (2.718)
a = Bend angle (radians) (see table below)
Degrees
Radians*
11.25°
.196
22.50°
.393
30°
.524
45°
.785
60°
1.047
90°
1.571
* 1 radian = 57.30°
A. For straight horizontal pulls: 
T_{2} = T_{1} + LWK 

B. For straight upward pulls: 
T_{2} = T_{1} + LW (sin T + K cos T) 

C. For straight downward pulls: 
T_{2} = T_{1}  LW (sin T  K cos T) 

D. For horizontal, upward, or downward pulls around bends: 
T_{2} = T_{1} e^{Ka} 