Panel Load Calculation Calculator for Utah
NEC 2023 panel load calculation math for EV charger installers working in Utah.
Adding EV chargers to an existing Utah service triggers an NEC 220 load calculation under 2023. The good news: NEC 220.83 and 220.87 both allow you to use the existing service's measured demand, but the EV load enters at 100% of its 125%-sized branch.
Worked example for Utah
On a typical 200 A single-family or small-commercial service in Utah, the existing demand plus a new 48 A Level 2 charger (60 A continuous-rated branch) fits comfortably under the service rating in most cases. When you add a second EVSE or a 19.2 kW charger, you usually need either a service upgrade or an NEC 625.42 energy-management system.
Code & Utilities
Utah currently enforces the NEC 2023 edition, adopted in 2024. 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.
Utah's primary EV-relevant utilities are Rocky Mountain Power, Murray City Power, Logan Light & Power. Their make-ready, time-of-use, and demand-charge structures vary widely; pull the specific tariff before sizing service equipment.
Climate & Ampacity
Utah's representative summer design ambient is around 99°F, which yields a 0.82× 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.
Utah takeaway
Rocky Mountain Power's service-upgrade timeline is the long-pole item here in Utah — running the panel-load math early lets you decide between an EMS-managed shared circuit and a full upgrade before you're past the point of no return.