EV Charger Load Calculator for Arizona
NEC 2017 ev charger load math for EV charger installers working in Arizona.
Sizing an EV charger circuit in Arizona starts with NEC 2017 Article 625 — the EVSE branch must be sized to 125% of the continuous load. Hot-climate extreme heat-band states like Arizona (108°F design ambient) also force a 0.75× ampacity correction at 75°C terminations.
Worked example for Arizona
For a 40 A Level 2 charger on a 240 V single-phase circuit, the OCPD is sized to 50 A (40 × 1.25 = 50.0 A, rounded up to the next standard breaker). The conductor must carry 50 A after Arizona's 0.75× correction — that typically lands at #8 AWG copper THWN-2 for a residential garage run, with conduit fill checked separately if you're stacking multiple home runs.
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
Always cross-check the EVSE manufacturer's listed maximum overcurrent rating; Arizona Public Service may also have specific service-upgrade or load-management requirements you'll need to coordinate before final inspection.