Cable Selection Calculator
Professional cable sizing with derating factors for electrical installations
Cable Selection Calculator
Compliant with IEC Standards & Cable Derating Factors
Results:
Full Load Current: 0.00 A
Total Derating Factor: 0.00
Required Cable Current: 0.00 A
Recommended Cable Size: -
Cable Derating Current: 0.00 A
How to Use the Calculator
Load Information
- Enter the total load power in kW
- Select system voltage (415V/400V for 3-phase, 230V/240V for single phase)
- Input power factor (typically 0.8 for motors)
- Specify cable length in meters
Environmental Conditions
- Select ambient temperature
- Choose ground temperature
- Pick soil type (affects thermal conductivity)
- Set cable burial depth
Installation Details
- Number of cables in same trench
- Cable spacing (affects heat dissipation)
- Calculator applies all derating factors
- Recommends appropriate cable size
Cable Derating Fundamentals
Derating Factors
Cable current capacity is affected by:
- K1: Air temperature correction
- K2: Ground temperature correction
- K3: Soil thermal resistance
- K4: Soil type correction
- K5: Cable depth correction
- K6: Cable distance correction
- K7: Cable grouping factor
Cable Selection
- Calculate full load current from power
- Apply all derating factors
- Select cable with adequate capacity
- Verify voltage drop is acceptable
Key Formulas:
Full Load Current = Power / (√3 × Voltage × PF)
Total Derating = K1 × K2 × K3 × K4 × K5 × K6 × K7
Cable Derating Current = Cable Current × Derating Factor
Calculation Formulas
Full Load Current:
I = P / (√3 × V × PF)
Total Derating Factor:
Kt = K1 × K2 × K3 × K4 × K5 × K6 × K7
Required Cable Current:
Ireq = I / Kt
Example Calculation
80kW Load, 415V, PF=0.8:
Full Load Current: 80,000 / (1.732 × 415 × 0.8) = 139A
Derating Factors: K1=0.94, K2=0.89, K4=1.05, K5=1.0, K6=1.0, K7=1.0
Total Derating: 0.94 × 0.89 × 1.05 × 1.0 × 1.0 × 1.0 = 0.88
Required Cable Current: 139 / 0.88 = 158A
Select cable with capacity ≥ 158A
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