Voltage Drop Calculator for Michigan
NEC 2017 voltage drop math for EV charger installers working in Michigan.
Michigan 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 Michigan
A 60 A Level 2 charger at 240 ft on 240 V single-phase #6 Cu shows roughly 5.9% drop. That's above the 3% NEC recommendation, so you'd upsize to #4 or #2 AWG to land back under 3%. Michigan's 0.88× ampacity correction is independent of voltage drop but applies on the same conductor pick.
Code & Utilities
EV installations in Michigan are governed by the 2017 National Electrical Code, in force since 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.
In Michigan, you'll most often interconnect with DTE Energy, Consumers Energy, Indiana Michigan Power. Their make-ready, time-of-use, and demand-charge structures vary widely; pull the specific tariff before sizing service equipment.
Climate & Ampacity
Michigan'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.
Michigan 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 Michigan will notice any drop above 5%.