Breaker Sizing Calculator for Kentucky
NEC 2020 breaker sizing math for EV charger installers working in Kentucky.
Every EVSE branch in Kentucky 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 Kentucky
A 80 A continuous EV load requires a breaker rated 100 A (80 × 1.25 = 100.0 A, rounded up to the next standard size). The conductor downstream must carry that 100 A after Kentucky's 0.88× ampacity correction.
Code & Utilities
Kentucky currently enforces the NEC 2020 edition, 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 Kentucky include LG&E and KU, Kentucky Power, East Kentucky Power Cooperative. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Kentucky's representative summer design ambient is around 92°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.
Kentucky takeaway
Use a 100%-rated breaker only when the panel and breaker are both listed for 100% continuous duty — otherwise the 125% rule applies. Kentucky inspectors enforce this rigorously on Article 625 work.