Solar energy is growing fast across the Aiken area, and for good reason. South Carolina receives an average of 5.0 to 5.2 peak sun hours per day, making it an excellent location for residential solar. But before panels go on your roof, there are critical electrical requirements that determine whether your home is ready for solar and how much the system will cost. Understanding these requirements helps you make informed decisions and avoid expensive surprises.
As licensed electricians who handle the electrical side of solar installations, we see homeowners regularly underestimate the electrical work involved. Solar is not just about panels on the roof. It involves inverters, panel capacity, rapid shutdown systems, metering, and interconnection with your utility. Here is what you need to know.
Inverter Types: String vs Microinverters vs Optimizers
Solar panels produce direct current (DC) electricity, but your home runs on alternating current (AC). An inverter converts DC to AC, and the type of inverter your system uses affects performance, cost, and electrical requirements.
- String inverters: A single inverter mounted near your electrical panel converts the output from all panels. This is the most affordable option, typically costing $1,000 to $2,000 for the inverter alone. The downside is that shading on one panel reduces output from the entire string. String inverters require a dedicated 240V circuit and wall space near the main panel.
- Microinverters: Each panel gets its own small inverter mounted directly underneath it. Enphase is the dominant brand. Microinverters allow each panel to operate independently, so shading on one panel does not affect the others. They cost more upfront but simplify the electrical connections at the panel level since AC power comes directly from the roof.
- Power optimizers with string inverter: SolarEdge is the leading example. Optimizers on each panel maximize individual panel output, while a central string inverter handles the DC-to-AC conversion. This hybrid approach offers many benefits of microinverters at a moderate price increase over basic string inverters.
For most Aiken homes, microinverters or optimizers are the better choice because roof configurations often include partial shading from trees, dormers, or multiple roof planes facing different directions.
Electrical Panel Capacity: Is Your Panel Ready?
Your electrical panel must have enough capacity to accommodate the solar interconnection. This is one of the most common issues we encounter. The NEC requires that the total of all breaker ratings on a panel, including the solar backfeed breaker, cannot exceed 120% of the panel's bus rating.
For example, a 200-amp panel with a 200-amp main breaker can accept a solar backfeed breaker of up to 40 amps (200 x 1.2 = 240; 240 - 200 = 40 amps). A 40-amp breaker supports roughly a 7.6 kW solar system, which is adequate for many Aiken homes.
If your home has a 100-amp panel or a 150-amp panel, the math often does not work without a panel upgrade. Older panels may also lack available breaker spaces for the solar connection. In these cases, upgrading to a 200-amp panel before solar installation is the practical path forward.
We evaluate panel capacity as the first step in any solar electrical assessment. If an upgrade is needed, it is far better to handle it before the solar installation rather than discovering the issue mid-project.
NEC Rapid Shutdown Requirements
The 2020 NEC, which South Carolina has adopted, requires rapid shutdown capability for rooftop solar systems. This safety feature allows firefighters to quickly de-energize the solar array to prevent electrocution during roof operations.
Under current code, conductors within the array boundary must be reduced to 80 volts or less within 30 seconds of initiating rapid shutdown. This means each panel or small group of panels needs module-level shutdown capability. Microinverters inherently comply with this requirement since each unit can be individually shut down. String inverter systems require additional rapid shutdown devices at each panel.
The rapid shutdown system connects to a clearly labeled disconnect switch near the utility meter, giving firefighters a single point to de-energize the entire rooftop array. Your electrician must install and label this disconnect according to NEC and local requirements.
Net Metering in South Carolina
Net metering determines how you get credit for excess solar electricity sent back to the grid. In South Carolina, Dominion Energy (the utility serving most of the Aiken area) offers net metering for residential solar systems up to 20 kW.
Under current net metering rules, excess electricity you send to the grid earns a credit on your bill at the retail rate. This means a kilowatt-hour you send to the grid offsets a kilowatt-hour you would otherwise purchase. Credits roll over month to month, allowing summer overproduction to offset higher winter bills when solar production is lower.
To participate in net metering, your system must be interconnected through a bi-directional meter. Dominion Energy typically replaces your existing meter with a net meter at no cost after your system passes inspection and the interconnection agreement is approved. The electrical work on your side of the meter must be completed and inspected before the utility will process the interconnection.
The Interconnection Process
Connecting a solar system to the grid follows a specific process in Aiken County:
- Step 1: Submit an interconnection application to Dominion Energy with system specifications, site plan, and single-line electrical diagram
- Step 2: Receive utility approval (typically 2 to 4 weeks)
- Step 3: Install the solar system and complete all electrical work
- Step 4: Pass the local electrical inspection (Aiken County building department)
- Step 5: Submit the inspection certificate to Dominion Energy
- Step 6: Utility installs the net meter and grants permission to operate
Do not energize your solar system before receiving permission to operate from the utility. Operating without approval can create safety hazards for utility workers and may violate your interconnection agreement.
Solar ROI in Aiken
With Aiken's strong solar resources and current incentives, residential solar typically pays for itself in 8 to 12 years. The federal Investment Tax Credit covers 30% of the total system cost, including electrical work. South Carolina does not currently offer a state solar tax credit, but the federal credit alone makes a significant impact.
A typical 8 kW system in Aiken costs $18,000 to $24,000 before the tax credit and $12,600 to $16,800 after the 30% federal credit. This system can produce 10,000 to 12,000 kWh per year, offsetting $1,200 to $1,500 in annual electricity costs at current Dominion Energy rates.
The electrical work portion of a solar installation, including the panel interconnection, rapid shutdown system, conduit runs, and any needed panel upgrades, typically represents 15% to 25% of the total project cost. Choosing a qualified electrician for this work ensures your system meets code, passes inspection the first time, and operates safely for decades.
Get Your Home Assessed for Solar
Before committing to a solar installation, have your electrical system evaluated by a licensed electrician. We can assess your panel capacity, identify any needed upgrades, and ensure your home's electrical infrastructure is ready for solar. Unity Power & Light works with solar installers throughout the Aiken area, handling the electrical connections that make your solar investment safe, code-compliant, and fully optimized. Contact us for a free electrical assessment.