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Solar site surveys · South CarolinaA technician on the roof, in the attic and at the service panel, with the survey read against the code editions, AHJs and utilities that apply in South Carolina.
South Carolina's Building Codes Council sets mandatory codes for every city and county: the 2021 IRC and IFC and the 2020 NEC with state modifications through 2026, then the 2024 codes and 2023 NEC from January 1, 2027. Export terms depend on the utility: Dominion Energy South Carolina and Duke Energy use PSC-approved Solar Choice time-of-use netting, while state-owned Santee Cooper nets hourly with a fixed export credit. Coastal sites like Charleston design for 150 mph winds and high seismic risk.
The capture spec is the same everywhere. What the engineer and the plan reviewer read it against is not.
The City of Charleston's design criteria list a 150 mph design wind speed and place the city in wind-borne debris zone 2, so racking, attachments and uplift checks are engineered for coastal hurricane loads.7
Charleston is in Seismic Design Category D2, and Charleston County's solar requirements ask for design analysis for both wind and seismic loads.7,8
Coastal design loads are driven by wind rather than snow: Charleston lists a 5 psf ground snow load and a 66.1 F mean annual temperature.7
Charleston County and Berkeley County flood maps both cover parts of the City of Charleston, so equipment elevation near the meter and service matters on low sites.7
Who reviews the plan set, and what the state layers on top.
The utility decides the interconnection path and what an exported kilowatt-hour is worth.
Customers who applied on or after June 1, 2021 take the Solar Choice rider on Rate 5 time-of-use service, up to 20 kW AC. Installers use PowerClerk and the SC Generator Interconnection Procedures.13,9
Interconnection page ↗Residential Solar Choice (Rider RSC) customers are served on the R-STOU time-of-use schedule, with systems up to 20 kW AC and a non-bypassable charge based on nameplate kW DC.10,14
Interconnection page ↗The state-owned utility's Distributed Generation Rider DG-25 allows residential systems up to the lesser of 20 kW or the customer's estimated maximum monthly demand, requires an interconnection application and fee, and adds a standby charge.15,16
Interconnection page ↗One standard, one visit, the same record in South Carolina as everywhere else. What it gets checked against is the code stack above.
The 2020 NEC with SC modifications, statewide since January 1, 2023. The Building Codes Council has adopted the 2023 NEC for local implementation on January 1, 2027.1,3
January 1, 2027. The Council adopted the 2024 IBC, IRC and IFC and the 2023 NEC with SC modifications on August 26, 2025, and the modifications were published in the State Register on May 22, 2026.2,3
Customers who applied before June 1, 2021 can keep the old terms until May 31, 2029. New DESC and Duke customers take Solar Choice time-of-use tariffs, and Santee Cooper uses its own hourly-netting rider.11,9,16
State law and the DESC and Duke solar choice riders cap residential customer-generators at 20 kW AC; Santee Cooper uses the lesser of 20 kW or estimated maximum monthly demand.11,10,16
Only with Building Codes Council approval; unapproved local modifications are invalid, so solar code rules are the same statewide even though permit processes differ.1
Metro pages for South Carolina: Charleston.
Roof, attic and service panel in one visit
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Explore →Every local fact on this page links to where it came from. Codes, programs and tariffs change: confirm the current requirement with the AHJ and the utility before you design.
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