About Wire Size Calculation

The wire size calculator helps you select the correct gauge of electrical wire for your project. It considers factors like current, voltage drop, conductor material, and operating temperature.

Key Principles

Wire size is determined by its cross-sectional area. A larger area allows more current to flow with lower resistance. The calculation is based on:

• Ohm's law (V = IR)
• Pouillet's law for wire resistance
• Temperature effects on wire resistivity

Important Considerations

The calculator provides recommendations to ensure safe electrical installations:

• Supports both DC and AC (single-phase and three-phase) systems
• Calculates wire size based on voltage drop (recommended max 5%)
• Accounts for wire length and operating temperature
• Supports copper and aluminum conductors

Example : Standard DC Circuit

Input

• Voltage: 120 V
• Current: 25 A
• Distance: 100 m
• Material: Copper
• Voltage Drop: 3%
• Temperature: 50°C

Calculation

The wire cross-sectional area is calculated using the formula:

A = Iϱ2L/v

=25×1.88×10^−8 × (2×100)/ 0.03 × 120

​

=2.61×10^−5m^2 × 1000000

=26.1 mm^2

=51.6 kcmil

=3 AWG

Output

Required Wire Cross-sectional Area: 26.16 mm²

Recommended Wire Gauge: 3 AWG