1. What is a Wire Pulling Tension Calculator?

Definition: This calculator estimates the tension required to pull wire through conduit based on friction, wire weight, length, and sidewall pressure.

Purpose: It helps electricians and engineers determine the pulling force needed for proper cable installation without exceeding maximum tension limits.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( T \) — Total pulling tension (newtons)
• \( \mu \) — Friction coefficient (dimensionless)
• \( W \) — Weight per unit length (N/m)
• \( L \) — Length of pull (meters)
• \( SWP \) — Sidewall pressure (newtons)

Explanation: The friction coefficient multiplied by the weight and length gives the basic friction force, plus any additional sidewall pressure from bends.

3. Importance of Tension Calculation

Details: Proper tension calculation prevents cable damage during installation, ensures worker safety, and helps select appropriate pulling equipment.

4. Using the Calculator

Tips: Enter the friction coefficient (default 0.5), wire weight in N/m, pull length in meters, and any sidewall pressure (default 0). All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical friction coefficient?
A: For lubricated pulls, μ is typically 0.2-0.5. For dry pulls, it can be 0.5-1.0 depending on materials.

Q2: How do I find wire weight per unit length?
A: Check manufacturer specifications or use standard tables based on wire gauge and type.

Q3: When would sidewall pressure be significant?
A: SWP becomes important when pulling through conduit bends (typically 0.5-1.5 N per degree of bend).

Q4: What's the maximum tension limit?
A: Generally 0.5-0.75 kN for copper, but always check cable specifications to avoid damage.

Q5: Does this account for multiple bends?
A: No, for complex pulls with multiple bends, use specialized software or consult NEC guidelines.