Breaker Sizing Calculator for Rhode Island
NEC 2020 breaker sizing math for EV charger installers working in Rhode Island.
Every EVSE branch in Rhode Island 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 Rhode Island
A 48 A continuous EV load requires a breaker rated 60 A (48 × 1.25 = 60.0 A, rounded up to the next standard size). The conductor downstream must carry that 60 A after Rhode Island's 0.94× ampacity correction.
Code & Utilities
The applicable code in Rhode Island 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 Rhode Island include Rhode Island Energy, Pascoag Utility District, Block Island Power. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Rhode Island's representative summer design ambient is around 86°F, which yields a 0.94× ampacity correction factor at 75°C terminations per NEC 310.15(B)(1). The correction is mild but still NEC-required; document it on the load calc so your inspector sees that 310.15(B) was applied.
Rhode Island takeaway
Use a 100%-rated breaker only when the panel and breaker are both listed for 100% continuous duty — otherwise the 125% rule applies. Rhode Island inspectors enforce this rigorously on Article 625 work.