Voltage Drop Calculator for New Hampshire
NEC 2020 voltage drop math for EV charger installers working in New Hampshire.
New Hampshire 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 New Hampshire
A 48 A Level 2 charger at 120 ft on 240 V single-phase #6 Cu shows roughly 2.4% drop. That's below the 3% NEC recommendation, so you'd stay at #6. New Hampshire's 0.88× ampacity correction is independent of voltage drop but applies on the same conductor pick.
Code & Utilities
New Hampshire currently enforces the NEC 2020 edition, 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.
New Hampshire's primary EV-relevant utilities are Eversource New Hampshire, Unitil, New Hampshire Electric Cooperative. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
New Hampshire's representative summer design ambient is around 87°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.
New Hampshire 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 New Hampshire will notice any drop above 5%.