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277V Voltage Drop Calculator

Preset for 277 V single-phase — commercial lighting circuits fed line-to-neutral from 480Y systems. A 3% budget at this voltage is 8.3 V.

Voltage Drop
Find Wire Size
Max Length
Advanced — units, power factor, parallel sets, energy cost
PASS
Voltage Drop
Percent Drop
Voltage at Load
Power Lost
Wire Resistance
Ampacity 75°C
0%3% branch5% total8%+

Max one-way distance at 3% (8.3 V) — copper

Size \ Amps15 A20 A30 A50 A100 A
14 AWG9068
12 AWG144108
10 AWG229172114
8 AWG363272181109
6 AWG564423282169
4 AWG899675450270
3 AWG1131848565339170
2 AWG14281071714428214
1 AWG17991349899540270
1/0 AWG227017031135681341
2/0 AWG286521481432859430
3/0 AWG3616271218081085542
4/0 AWG4556341722781367683

Cells are blank where the size is below the 75 °C ampacity for that load.

Frequently Asked Questions

What is 3% of 277 volts?

8.3 V — the recommended maximum branch-circuit drop at this voltage. The 5% total budget is 13.9 V.

Built & maintained by Murugan Vellaichamy · Every calculation verified against NEC Chapter 9 Table 8 & Table 310.16 published values · Informational reference — not engineering advice