Breaker Sizing Calculator for New York
NEC 2017 breaker sizing math for EV charger installers working in New York.
Every EVSE branch in New York is treated as a continuous load per NEC 2017 Article 625 — the OCPD must be sized at 125% of the EVSE's listed maximum draw.
Worked example for New York
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 New York's 0.88× ampacity correction.
Code & Utilities
New York currently enforces the NEC 2017 edition, adopted in 2020. That includes Article 625 EVSE rules and the 125% continuous-load factor on charging branch circuits, though some 2020-cycle changes (like expanded EMS provisions) are not yet enforced statewide.
Major electric utilities serving New York include Con Edison, National Grid, PSEG Long Island, NYSEG, Central Hudson. Their make-ready, time-of-use, and demand-charge structures vary widely; pull the specific tariff before sizing service equipment.
Climate & Ampacity
New York's representative summer design ambient is around 88°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.
New York takeaway
Use a 100%-rated breaker only when the panel and breaker are both listed for 100% continuous duty — otherwise the 125% rule applies. New York inspectors enforce this rigorously on Article 625 work.