EV Charger Load Calculator for Connecticut
NEC 2020 ev charger load math for EV charger installers working in Connecticut.
Sizing an EV charger circuit in Connecticut starts with NEC 2020 Article 625 — the EVSE branch must be sized to 125% of the continuous load. Hot-climate mild-band states like Connecticut (87°F design ambient) also force a 0.88× ampacity correction at 75°C terminations.
Worked example for Connecticut
For a 40 A Level 2 charger on a 240 V single-phase circuit, the OCPD is sized to 50 A (40 × 1.25 = 50.0 A, rounded up to the next standard breaker). The conductor must carry 50 A after Connecticut's 0.88× correction — that typically lands at #8 AWG copper THWN-2 for a residential garage run, with conduit fill checked separately if you're stacking multiple home runs.
Code & Utilities
The applicable code in Connecticut 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 Connecticut include Eversource Energy, United Illuminating, Connecticut Municipal Electric. Always verify the applicable tariff and any utility-specific requirements (CT cabinets, metering enclosures, demand limiters) at design time.
Climate & Ampacity
Connecticut'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.
Connecticut takeaway
Always cross-check the EVSE manufacturer's listed maximum overcurrent rating; Eversource Energy may also have specific service-upgrade or load-management requirements you'll need to coordinate before final inspection.