Breaker Sizing Calculator for Delaware
NEC 2020 breaker sizing math for EV charger installers working in Delaware.
Every EVSE branch in Delaware is treated as a continuous load per NEC 2020 Article 625 — the OCPD must be sized at 125% of the EVSE's listed maximum draw.
Worked example for Delaware
A 40 A continuous EV load requires a breaker rated 50 A (40 × 1.25 = 50.0 A, rounded up to the next standard size). The conductor downstream must carry that 50 A after Delaware's 0.88× ampacity correction.
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
Use a 100%-rated breaker only when the panel and breaker are both listed for 100% continuous duty — otherwise the 125% rule applies. Delaware inspectors enforce this rigorously on Article 625 work.