EV Charger Load Calculator for Wyoming
NEC 2017 ev charger load math for EV charger installers working in Wyoming.
Sizing an EV charger circuit in Wyoming starts with NEC 2017 Article 625 — the EVSE branch must be sized to 125% of the continuous load. Hot-climate warm-band states like Wyoming (90°F design ambient) also force a 0.88× ampacity correction at 75°C terminations.
Worked example for Wyoming
For a 48 A Level 2 charger on a 240 V single-phase circuit, the OCPD is sized to 60 A (48 × 1.25 = 60.0 A, rounded up to the next standard breaker). The conductor must carry 60 A after Wyoming's 0.88× correction — that typically lands at #6 AWG copper THWN-2 for a residential garage run, with conduit fill checked separately if you're stacking multiple home runs.
Code & Utilities
The applicable code in Wyoming is the NEC 2017, which the state 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 Wyoming include Rocky Mountain Power, Black Hills Energy, Wyoming Rural Electric Cooperatives. Always verify the applicable tariff and any utility-specific requirements (CT cabinets, metering enclosures, demand limiters) at design time.
Climate & Ampacity
Wyoming's representative summer design ambient is around 90°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.
Wyoming takeaway
Always cross-check the EVSE manufacturer's listed maximum overcurrent rating; Rocky Mountain Power may also have specific service-upgrade or load-management requirements you'll need to coordinate before final inspection.