Voltage Drop Calculator for Oregon
NEC 2023 voltage drop math for EV charger installers working in Oregon.
Oregon EV installs frequently push past 100 ft of conductor — detached garages, parking-lot DCFC pedestals, and multifamily carport runs all add distance. NEC 2023 recommends a 3% branch / 5% total voltage-drop ceiling.
Worked example for Oregon
A 48 A Level 2 charger at 240 ft on 240 V single-phase #6 Cu shows roughly 4.7% drop. That's above the 3% NEC recommendation, so you'd upsize to #4 or #2 AWG to land back under 3%. Oregon's 0.88× ampacity correction is independent of voltage drop but applies on the same conductor pick.
Code & Utilities
The applicable code in Oregon is the NEC 2023, which the state adopted in 2024. That includes Article 625 (Electric Vehicle Power Transfer System) requirements: 125% continuous-load sizing on EVSE branch circuits, GFCI protection at outdoor receptacles, and provisions for energy management systems on shared circuits.
In Oregon, you'll most often interconnect with Portland General Electric, Pacific Power, Eugene Water & Electric Board. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Oregon's representative summer design ambient is around 88°F, which yields a 0.88× ampacity correction factor at 75°C terminations per NEC 310.15(B)(1). Because the correction is below 0.9, conductors that "look fine" on a 30°C ampacity table will not carry their nameplate current here — always derate explicitly.
Oregon takeaway
Voltage drop is a recommendation, not a hard NEC rule — but EVSEs throttle aggressively below ~228 V on a 240 V circuit, so customers in Oregon will notice any drop above 5%.