The calculation of cable pulling tension is critical for ensuring a safe and successful installation, preventing damage to the cable's conductors and insulation. The process involves a series of formulas that account for various factors. The total tension is the sum of forces from straight sections and curved sections (bends), with the highest tension typically occurring at the end of the pull.

For a straight section, the tension is calculated as: T = L × W × f Where:

• T = Tension

• L = Length of the section

• W = Weight of the cable per unit length

• f = Coefficient of friction

For a curved section, the tension is a multiplication of the tension entering the bend: T_out = T_in × e^(f × α) Where:

• T_out = Tension exiting the bend

• T_in = Tension entering the bend

• e = Euler's number (approximately 2.718)

• f = Coefficient of friction

• α = Angle of the bend in radians

The maximum allowable pulling tension for conductors is also a key consideration and is typically determined by the cable's circular mil area (CMA). For pulling with an eye attached to the conductors, a common formula is: T_max = k × n × CMA Where:

• T_max = Maximum allowable tension

• k = A constant (e.g., 0.008 for copper, 0.006 for aluminum)

• n = Number of conductors

• CMA = Circular mil area of one conductor

We recommend using specialized software or a detailed engineering analysis to perform these calculations accurately. Our state-of-the-art stringing equipment is designed to work within these safe parameters, ensuring the integrity of your cables.