Home Electrical Engineering Cable Capacity Calculator

⚡ Cable Current Carrying Capacity Calculator

Calculate current carrying capacity, determine required cable cross-section area, analyze voltage drop, and apply derating factors for electrical conductors and cables.

Calculation Mode

Cable Parameters

Cable Configuration

Analysis Results

Select calculation mode and enter parameters to see results

Standard Cable Ratings (IEC 60364)

Current Carrying Capacity

The ampacity of a conductor depends on several factors:

I = I₀ × CF × CT × CG
Current = Base Current × Correction Factors
  • CF: Installation method correction factor
  • CT: Temperature correction factor
  • CG: Grouping/bundling correction factor

Cross Section Calculation

Cable cross-section is determined by current requirements and voltage drop:

A = (ρ × I × L) / (ΔV × 1000)
Area = (Resistivity × Current × Length) / Voltage Drop
A = I / J
Area = Current / Current Density

Voltage Drop

Voltage drop limits for different circuit types:

  • Lighting Circuits: 3% max voltage drop
  • Power Circuits: 5% max voltage drop
  • Motor Circuits: 10% starting, 5% running
  • Long Runs: May require larger conductors
ΔV = (ρ × I × L) / A
Voltage Drop = (Resistivity × Current × Length) / Area

Derating Factors

  • Temperature: Higher ambient temperatures reduce capacity
  • Grouping: Multiple cables reduce heat dissipation
  • Installation: Conduit vs. open air affects cooling
  • Soil Conditions: Thermal resistivity for buried cables
  • Load Factor: Continuous vs. intermittent loading