Wire Size Calculator for Delaware
NEC 2020 wire size math for EV charger installers working in Delaware.
Wire sizing in Delaware 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 Delaware
A 50 A continuous EV branch needs a conductor whose corrected ampacity meets or exceeds 50 A. In Delaware's 0.88× correction, that means picking a conductor whose 30°C-rated ampacity is at least 57 A. For copper THWN-2 in EMT, that typically lands at #6 AWG; aluminum requires one to two sizes larger.
Code & Utilities
The applicable code in Delaware 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.
Delaware's primary EV-relevant utilities are Delmarva Power, Delaware Electric Cooperative, Delaware Municipal Electric. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Plan EV feeders against a 91°F ambient in Delaware — the resulting NEC 310.15(B) correction of 0.88× is what trims a #6 THWN-2 down to its true continuous rating. 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.
Delaware 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 Delaware.