Breaker Sizing Calculator for Connecticut
NEC 2020 breaker sizing math for EV charger installers working in Connecticut.
Every EVSE branch in Connecticut 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 Connecticut
A 60 A continuous EV load requires a breaker rated 75 A (60 × 1.25 = 75.0 A, rounded up to the next standard size). The conductor downstream must carry that 75 A after Connecticut's 0.88× ampacity correction.
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
Use a 100%-rated breaker only when the panel and breaker are both listed for 100% continuous duty — otherwise the 125% rule applies. Connecticut inspectors enforce this rigorously on Article 625 work.