Wire Size Calculator for New Jersey
NEC 2020 wire size math for EV charger installers working in New Jersey.
Wire sizing in New Jersey is governed by NEC 2020 Table 310.16, with the state's 91°F summer ambient driving a 0.88× correction factor at 75°C terminations per Table 310.15(B)(1).
Worked example for New Jersey
A 70 A continuous EV branch needs a conductor whose corrected ampacity meets or exceeds 70 A. In New Jersey's 0.88× correction, that means picking a conductor whose 30°C-rated ampacity is at least 80 A. For copper THWN-2 in EMT, that typically lands at #4 AWG; aluminum requires one to two sizes larger.
Code & Utilities
New Jersey currently enforces the NEC 2020 edition, adopted in 2021. 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.
In New Jersey, you'll most often interconnect with PSE&G, Atlantic City Electric, JCP&L, Orange & Rockland. Always verify the applicable tariff and any utility-specific requirements (CT cabinets, metering enclosures, demand limiters) at design time.
Climate & Ampacity
New Jersey's representative summer design ambient is around 91°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 Jersey takeaway
Don't forget conduit-fill derating per NEC 310.15(C)(1) when more than three current-carrying conductors share a raceway — a common condition on multifamily and workplace EVSE home-run racks in New Jersey.