📊 Calculate Voltage Drop
📊 Results
Voltage Drop
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Drop %
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Voltage at Load
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Recommendation
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📚 NEC Voltage Drop Requirements
The National Electrical Code (NEC) recommends:
3% maximum voltage drop for branch circuits
5% maximum voltage drop for feeder circuits
Total maximum voltage drop (branch + feeder) should not exceed 5%
📐 Formula
Single Phase:
VD = (2 × K × I × L) / CM
Three Phase:
VD = (1.732 × K × I × L) / CM
K = Resistivity (10.4 for copper, 17.0 for aluminum)
I = Current in amps
L = Length in feet
CM = Wire area in circular mils