Construction
Voltage Drop Calculator
How much voltage loss over a wire run. Too much drop = dim lights, weak motors, tripped breakers.
Voltage drop
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- % drop
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- Voltage at load
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- Pass 3% rule?
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FAQ
Total loop length? +
Use one-way distance — the formula accounts for both directions (hot + neutral).
Why 12.9 / 21.2? +
Standard k values for circular-mil resistance at 75C for copper and aluminum respectively.