Voltage Drop Calculator for Arizona
NEC 2017 voltage drop math for EV charger installers working in Arizona.
Arizona EV installs frequently push past 100 ft of conductor — detached garages, parking-lot DCFC pedestals, and multifamily carport runs all add distance. NEC 2017 recommends a 3% branch / 5% total voltage-drop ceiling.
Worked example for Arizona
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%. Arizona's 0.75× ampacity correction is independent of voltage drop but applies on the same conductor pick.
Code & Utilities
EV installations in Arizona are governed by the 2017 National Electrical Code, in force since 2018. That includes Article 625 EVSE rules and the 125% continuous-load factor on charging branch circuits, though some 2020-cycle changes (like expanded EMS provisions) are not yet enforced statewide.
Major electric utilities serving Arizona include Arizona Public Service, Salt River Project, Tucson Electric Power. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Plan EV feeders against a 108°F ambient in Arizona — the resulting NEC 310.15(B) correction of 0.75× is what trims a #6 THWN-2 down to its true continuous rating. 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.
Arizona 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 Arizona will notice any drop above 5%.