When the power goes out in Aiken, you have a decision to make long before the storm hits: how will your portable or standby generator connect to your home safely? You cannot simply plug a generator into a wall outlet or run extension cords to your appliances. That approach is dangerous, against code, and limited in what it can power. The two legitimate options are a generator interlock kit and an automatic transfer switch (ATS). Both are code-compliant, both protect utility workers from deadly backfeed, and both let you power your home's circuits through your existing breaker panel. But they differ significantly in cost, convenience, and how much involvement they require from you during an outage.
How a Generator Interlock Kit Works
An interlock kit is a mechanical sliding plate that mounts directly onto your electrical panel's cover. It physically prevents your main breaker and a dedicated generator inlet breaker from being turned on at the same time. When you want to run your home on generator power, you slide the interlock plate over, turn off the main breaker (which disconnects your house from the utility grid), and then turn on the generator inlet breaker. Power from your portable generator flows through a heavy-duty cord into a weatherproof inlet box mounted on the outside of your house, through the generator breaker, and into your panel.
Here is the important part: with an interlock kit, you use your existing circuit breakers to choose what to power. You manually turn off the breakers for circuits you do not need (like your electric dryer or oven) and leave on the ones you want (like your refrigerator, a few lights, the well pump, or your internet router). This gives you flexibility because you are not limited to a pre-selected set of circuits. You can change your mind and shift loads around as long as you stay within your generator's wattage capacity.
The installation itself is straightforward. An electrician mounts the interlock plate on your panel, installs a new double-pole breaker sized to match your generator's output (typically 30 amps for most portable generators), runs wiring from that breaker to a weatherproof power inlet box on the exterior of your home, and verifies everything is properly grounded. The whole job typically takes two to four hours.
How an Automatic Transfer Switch Works
An automatic transfer switch is a standalone electrical device installed between your utility meter and your breaker panel (or between the panel and a subpanel). It monitors your incoming utility power 24 hours a day. When it detects a power loss, it sends a signal to your standby generator to start. Once the generator is running and producing stable voltage, the ATS disconnects your home from the grid and connects it to the generator, all within about 10 to 30 seconds and without any action from you.
When utility power is restored, the ATS detects the stable incoming power, transfers your home back to the grid, and signals the generator to shut down after a brief cool-down period. You may not even realize the power went out if you were not home.
There are two main types. A whole-house ATS is rated for your full service amperage (typically 200 amps) and, when paired with a large enough standby generator, can power your entire home as if nothing happened. A load-center ATS powers a pre-selected set of circuits, usually 10 to 16 of them, that you and your electrician choose during installation. The load-center version is less expensive because it requires a smaller generator.
Cost Comparison: What to Budget
Cost is often the deciding factor, and the difference between these two options is substantial.
A generator interlock kit installed typically runs $800 to $1,500 in the Aiken area. That includes the interlock plate, the new breaker, the power inlet box, wiring, and labor. You do need to already own a portable generator (or plan to buy one separately), which adds $500 to $2,000 depending on size and fuel type.
An automatic transfer switch installed costs $2,500 to $4,500 or more, depending on the amperage rating and whether it is a load-center or whole-house unit. The ATS hardware itself accounts for roughly half of that cost, with the remainder going to labor, wiring, and permitting.
A complete standby generator system with an ATS, which includes a permanently installed natural gas or propane generator on a concrete pad outside your home, typically ranges from $7,000 to $15,000+ installed. The wide range reflects the generator's size (kilowatt output), fuel source, and the complexity of your installation, such as whether your electrical panel needs an upgrade to accommodate the new equipment.
Interlock Kit: Advantages and Drawbacks
Advantages: The interlock kit's biggest selling point is affordability. For under $1,500, you get a code-compliant way to power your home during outages. You also get flexibility because you are not locked into a fixed set of circuits. If you need to run the well pump for 20 minutes and then switch to the air conditioning, you can do that just by flipping breakers. The interlock works with any properly sized portable generator, so if you already own one, you are most of the way there.
Drawbacks: Everything is manual. When the power goes out at 2:00 AM, you need to get up, go outside, start the generator, come back inside, slide the interlock, turn off the main breaker, turn on the generator breaker, and then manage your loads. If you are away from home, nothing happens. Your refrigerator and freezer sit without power until you get back. You also need to monitor your generator's fuel level and refuel it periodically.
Automatic Transfer Switch: Advantages and Drawbacks
Advantages: Convenience is the ATS's clear strength. You do not need to be home, awake, or even in the state for your backup power to kick in. That matters for perishable food, sump pumps, medical equipment, and home security systems. A standby generator paired with an ATS can run indefinitely on natural gas or for days on a propane tank without any intervention. For homeowners who travel frequently or have family members with medical needs, this peace of mind is worth the higher cost.
Drawbacks: The cost is two to ten times higher than an interlock kit. A load-center ATS limits you to a pre-selected set of circuits, so if you later decide you want a different circuit on backup power, an electrician may need to reconfigure the wiring. Standby generators also require annual maintenance, including oil changes, filter replacements, and exercise runs to keep the engine ready.
When an Interlock Kit Makes More Sense
An interlock kit is the right choice for homeowners who already own a reliable portable generator and want a safe, legal way to connect it. It makes sense if your power outages are infrequent and you are typically home when they happen. Aiken homeowners on a tighter budget who still want whole-panel access during outages will get the most value from this option. It is also a practical choice if you are planning to upgrade to a standby system in the future but want backup power in the meantime.
When an Automatic Transfer Switch Makes More Sense
If you travel often, work away from home during the day, or have someone in your household who depends on electrically powered medical equipment like a CPAP machine or oxygen concentrator, automatic operation is not a luxury but a necessity. An ATS paired with a standby generator also makes sense if your home has a sump pump protecting a finished basement, if you keep significant amounts of food in freezers, or if you simply do not want to deal with the manual process of starting a generator and managing loads in the dark during a storm.
Aiken and the surrounding CSRA area experience severe thunderstorms, occasional tropical storm remnants, and ice storms that can knock out power for hours or days. Homeowners in more rural areas outside of town, where utility restoration tends to take longer, benefit the most from automatic standby systems.
South Carolina Code and Safety Requirements
Both interlock kits and automatic transfer switches are fully compliant with the National Electrical Code (NEC) when installed by a licensed electrician. South Carolina requires that any connection between a generator and your home's wiring go through an approved transfer mechanism. The reason is backfeed prevention. Without an interlock or transfer switch, your generator can energize the utility lines running from your house back to the transformer and into the grid. Utility workers repairing downed lines have been killed by backfed electricity from improperly connected generators.
An interlock kit prevents backfeed mechanically because the sliding plate makes it physically impossible to have both the main breaker and the generator breaker on simultaneously. An ATS prevents backfeed electrically because its internal switching mechanism creates a break-before-make connection that never allows utility and generator power to be connected at the same time.
Both installations require a permit in Aiken County. A licensed electrician handles the permit application and schedules the inspection, so you do not need to manage that process yourself.
Why Professional Installation Is Non-Negotiable
We cannot stress this enough: generator connections are not a DIY project. Improper installation can create backfeed that endangers utility line workers and neighbors. It can also damage your generator, fry sensitive electronics in your home, or start a fire. Beyond safety, Dominion Energy and other local utilities require that generator interconnections be installed by a licensed contractor and inspected before use. If your generator connection was not installed with a permit, your homeowner's insurance may deny a claim related to generator use.
A professional installation also ensures your wiring is sized correctly for your generator's output, your grounding is proper, and your inlet box is rated for outdoor use. These details matter, especially in Aiken's humid climate where outdoor electrical components are exposed to moisture year-round.
Making Your Decision
Start by asking yourself three questions. First, do you already own a portable generator, or are you open to purchasing a permanently installed standby unit? Second, are you typically home during power outages, or could you be away? Third, what is your budget? If you want safe, code-compliant backup power for under $1,500 and you do not mind the manual process, an interlock kit is an excellent solution. If you want automatic, hands-free operation and your budget allows for a larger investment, an automatic transfer switch with a standby generator is the way to go.
Either way, you are making a smart investment. Backup power protects your food, your comfort, your home's mechanical systems, and in some cases, your family's health. The key is getting it installed safely and legally by a licensed electrician who can match the solution to your home's electrical system and your specific needs.