Conduit Fill Calculator

Calculate conduit fill percentage per NEC Chapter 9. Supports EMT, IMC, and RMC conduit types.

Results

Fill Percentage

4.6%

Max Conductors

21

Status

✓ COMPLIANT

NEC Conduit Fill Requirements

Number of ConductorsMaximum Fill
1 conductor53%
2 conductors31%
3 or more conductors40%

Understanding Conduit Fill Calculations

NEC Chapter 9, Table 1 specifies the maximum percentage of conduit cross-sectional area that can be occupied by conductors. This ensures adequate space for heat dissipation and ease of wire pulling.

Why Conduit Fill Matters

  • Prevents overheating of conductors
  • Allows for easier wire installation and pulling
  • Ensures compliance with electrical codes
  • Maintains conductor insulation integrity

Related Tools

For box fill calculations, use our box fill calculator. Check the wire gauge chart for conductor volume allowances.