NEC 2026 Compatible

What is the voltage drop on a single-phase 120V circuit with 20A load, 100 feet of 12 AWG copper? (K = 12.9, CM of 12 AWG = 6,530)

Journeyman Level📋 NEC Chapter 9, Table 8Voltage Drop
Circuit Diagram
Voltage Drop Calculation — NEC 210.19(A) Info Note SOURCE PANEL 120V Hot — #12 AWG Cu Neutral — #12 AWG Cu 91 ft one-way LOAD 10A 116.4V Vd = 3.6V 3.0% Voltage Drop NEC recommends ≤3% branch circuit, ≤5% total (branch + feeder) Vd = (2 × K × I × D) / cmil K=12.9(Cu) I=10A D=91ft cmil=6530(#12) Vd = (2 × 12.9 × 10 × 91) / 6530 = 3.60V (3.0%)
A

2.37 volts

B

3.95 volts

C

5.29 volts

D

7.92 volts

Explanation & Direct Citation

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