Voltage Drop Calculator for Rhode Island
NEC 2020 voltage drop math for EV charger installers working in Rhode Island.
Rhode Island EV installs frequently push past 100 ft of conductor — detached garages, parking-lot DCFC pedestals, and multifamily carport runs all add distance. NEC 2020 recommends a 3% branch / 5% total voltage-drop ceiling.
Worked example for Rhode Island
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%. Rhode Island's 0.94× ampacity correction is independent of voltage drop but applies on the same conductor pick.
Code & Utilities
The applicable code in Rhode Island is the NEC 2020, which the state adopted in 2022. 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.
Major electric utilities serving Rhode Island include Rhode Island Energy, Pascoag Utility District, Block Island Power. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Rhode Island's representative summer design ambient is around 86°F, which yields a 0.94× ampacity correction factor at 75°C terminations per NEC 310.15(B)(1). The correction is mild but still NEC-required; document it on the load calc so your inspector sees that 310.15(B) was applied.
Rhode Island 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 Rhode Island will notice any drop above 5%.