Breaker Sizing Calculator for Pennsylvania
NEC 2020 breaker sizing math for EV charger installers working in Pennsylvania.
Every EVSE branch in Pennsylvania 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 Pennsylvania
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 Pennsylvania's 0.88× ampacity correction.
Code & Utilities
Pennsylvania 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.
Pennsylvania's primary EV-relevant utilities are PECO, PPL Electric Utilities, Duquesne Light, FirstEnergy Pennsylvania. Their make-ready, time-of-use, and demand-charge structures vary widely; pull the specific tariff before sizing service equipment.
Climate & Ampacity
In Pennsylvania, the 89°F summer ambient drives a 0.88× 75°C ampacity correction. Bake this into every Level 2 and DCFC conductor pick before you commit to a wire size. 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.
Pennsylvania takeaway
Use a 100%-rated breaker only when the panel and breaker are both listed for 100% continuous duty — otherwise the 125% rule applies. Pennsylvania inspectors enforce this rigorously on Article 625 work.