Voltage Drop Calculator for Ohio
NEC 2017 voltage drop math for EV charger installers working in Ohio.
Ohio 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 Ohio
A 40 A Level 2 charger at 320 ft on 240 V single-phase #6 Cu shows roughly 5.2% drop. That's above the 3% NEC recommendation, so you'd upsize to #4 or #2 AWG to land back under 3%. Ohio's 0.88× ampacity correction is independent of voltage drop but applies on the same conductor pick.
Code & Utilities
Ohio currently enforces the NEC 2017 edition, adopted in 2020. 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.
Ohio's primary EV-relevant utilities are AEP Ohio, Duke Energy Ohio, FirstEnergy, DP&L. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Ohio's representative summer design ambient is around 89°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.
Ohio 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 Ohio will notice any drop above 5%.