Wire Size Calculator | PES Supply

Wire Size Calculator

Find the correct AWG wire size for any amp load and distance

Recommended Wire Size
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How Wire Size is Calculated

The calculator uses NEC Table 310.16 ampacity ratings and voltage drop formula:

Step 1: Find minimum AWG that can carry the current (ampacity check)

Step 2: Calculate voltage drop: VD = 2 × L × R × I / 1000

Step 3: If VD > max%, increase wire size until within limit

Copper Wire Ampacity (75°C, NEC Table 310.16)

AWG Ampacity Resistance (Ω/1000ft)
14 AWG 20A 2.525
12 AWG 25A 1.588
10 AWG 35A 0.999
8 AWG 50A 0.628
6 AWG 65A 0.395
4 AWG 85A 0.249
2 AWG 115A 0.156
1/0 AWG 150A 0.098
2/0 AWG 175A 0.078
4/0 AWG 230A 0.049