Cable Duct Size Calculator

Accurate cable duct sizing for electrical installations

Cable Duct Size Calculator

Compliant with NEC and IEC Standards

Results:

Total Cable Area: 0.00 mm²

Required Duct Area: 0.00 mm²

Recommended Duct Size: 0.00 mm

How to Use the Calculator

Power Cables

  1. Select "Power Cable" type
  2. Enter cable outer diameter
  3. Specify number of cables
  4. Choose appropriate fill factor
  5. Select duct shape preference

Control Cables

  1. Select "Control Cable" type
  2. Enter cable diameter including jacket
  3. Input total cable count
  4. Use standard 40% fill factor
  5. Choose optimal duct configuration

Data Cables

  1. Select "Data Cable" type
  2. Measure cable outer diameter
  3. Count all cable runs
  4. Consider future expansion needs
  5. Select appropriate duct shape

Cable Duct Sizing Fundamentals

Fill Factor

Fill factor determines cable density:

  • 40% - Standard installations
  • 50% - High density applications
  • 60% - Maximum allowable fill

Duct Shapes

  • Round - Most efficient space usage
  • Square - Easy installation
  • Rectangular - Multiple cable layers

Key Formulas:

Cable Area = π × (D/2)² × N

Duct Area = Cable Area / Fill Factor

Round Duct: D = √(4 × Area / π)

Calculation Formulas

Total Cable Area:
A_cable = π × (D/2)² × N

Required Duct Area:
A_duct = A_cable / (Fill Factor / 100)

Round Duct Diameter:
D_duct = √(4 × A_duct / π)

Example Calculation

Power Cable Installation:

Cable Diameter: 25mm

Number of Cables: 4

Fill Factor: 40%

Cable Area = π × (25/2)² × 4 = 1963.5 mm²

Duct Area = 1963.5 / 0.4 = 4908.7 mm²

Round Duct Diameter = √(4 × 4908.7 / π) = 79.0 mm

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