Voltage Drop Calculator
Compute the percentage drop across a feeder or branch circuit quickly.
Result
Volts dropped
5.99 V
Percent drop
2.50%
Status
ok
For long feeders use copper where possible, and target ≤3% on feeder and ≤5% branch (NEC 215.2 / 210.19(A)(1)).
About this tool
Estimate conductor voltage drop for copper or aluminum runs at any standard system voltage. Built around the recurring r/electricians debates about 80% rule loads and 3% feeder plus 5% branch NEC 215.2 / 210.19(A)(1) limits.
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