Panel Load Calculation Calculator for South Carolina
NEC 2017 panel load calculation math for EV charger installers working in South Carolina.
Adding EV chargers to an existing South Carolina service triggers an NEC 220 load calculation under 2017. 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 South Carolina
On a typical 320 A single-family or small-commercial service in South Carolina, 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
The applicable code in South Carolina is the NEC 2017, which the state adopted in 2018. 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 South Carolina include Duke Energy Carolinas SC, Dominion Energy South Carolina, Santee Cooper. Their make-ready, time-of-use, and demand-charge structures vary widely; pull the specific tariff before sizing service equipment.
Climate & Ampacity
South Carolina's representative summer design ambient is around 94°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.
South Carolina takeaway
Duke Energy Carolinas SC's service-upgrade timeline is the long-pole item here in South Carolina — 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.