1. What is the Cable Pulling Formula?

The cable pulling formula calculates the output tension (T_out) based on input tension (T_in), coefficient of friction (μ), and the angle of bend (θ). This equation is essential for determining the forces involved in cable installation through conduits.

2. How Does the Calculator Work?

The calculator uses the cable pulling formula:

Where:

• \( T_{in} \) — Input tension (lb or N)
• \( \mu \) — Coefficient of friction (dimensionless)
• \( \theta \) — Angle of bend (radians)
• \( e \) — Euler's number (approximately 2.71828)

Explanation: The formula calculates how tension increases exponentially as a cable is pulled around bends due to friction.

3. Importance of Cable Pulling Calculation

Details: Accurate tension calculation is crucial for preventing cable damage during installation, ensuring proper conduit sizing, and determining the required pulling equipment capacity.

4. Using the Calculator

Tips: Enter input tension in lb or N, coefficient of friction (typically 0.1-0.5 for most cable/conduit combinations), and bend angle in radians. All values must be valid (tension > 0, μ ≥ 0, θ ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: What are typical coefficient of friction values?
A: For most cable/conduit combinations, μ ranges from 0.1 to 0.5. Lubricated pulls typically have μ = 0.1-0.2, while dry pulls may have μ = 0.3-0.5.

Q2: How do I convert degrees to radians?
A: Multiply degrees by π/180 (approximately 0.0174533). A 90° bend equals approximately 1.57 radians.

Q3: What is the maximum recommended pulling tension?
A: Maximum tension varies by cable type but is typically 0.008 lb/circular mil for copper and 0.006 lb/circular mil for aluminum.

Q4: Does this formula account for multiple bends?
A: For multiple bends, calculate sequentially: T_out from first bend becomes T_in for second bend, and so on.

Q5: When should I use this calculation?
A: Use for planning cable pulls through conduits with bends to ensure tension stays within cable and equipment limits.