Grounding Conductor Calculator for South Carolina
NEC 2017 grounding conductor math for EV charger installers working in South Carolina.
EGC sizing in South Carolina follows NEC 2017 Table 250.122, indexed off the upstream OCPD rating, with parallel rules for parallel sets and increased-conductor adjustments under 250.122(B).
Worked example for South Carolina
For a 100 A EVSE branch, Table 250.122 calls for a minimum #8 Cu equipment grounding conductor. If you upsize the phase conductors for voltage drop in South Carolina's long runs, NEC 250.122(B) requires the EGC to be upsized proportionally.
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
On DCFC sites with parallel feeder sets, each parallel raceway needs its own full-size EGC — a detail inspectors in South Carolina catch frequently on commercial submittals.