Voltage drop grows with distance — upsize the wire to fix it

Voltage drop is a long-run problem: it rises with amps and distance and falls as the wire gets fatter — upsizing is the fix.

A line graph of voltage versus one-way run length. A 12 AWG conductor drops steeply and crosses the 3 percent target line (232.8 volts) at about 130 feet, while a 10 AWG conductor drops more gently and stays above it. Voltage drop equals 2 times K times current times length divided by circular mils, so it rises with amps and distance and falls as the wire gets fatter. The 3 and 5 percent targets are recommendations, not code. — Source: K-factor method; NEC Informational Notes to 210.19/215.2

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A line graph of voltage versus one-way run length. A 12 AWG conductor drops steeply and crosses the 3 percent target line (232.8 volts) at about 130 feet, while a 10 AWG conductor drops more gently and stays above it. Voltage drop equals 2 times K times current times length divided by circular mils, so it rises with amps and distance and falls as the wire gets fatter. The 3 and 5 percent targets are recommendations, not code.

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