Short answer: A whole-house (standby) generator is wired into your home’s electrical system through a transfer switch. That means it needs an electrical permit and an inspection, and a gas permit if it runs on natural gas or propane. Sizing depends on what you want to keep running during an outage: the whole house, or only the essentials. The cost depends on five things: the generator’s size, the fuel it runs on, the type of transfer switch, the permits, and the installation work at your house. An article cannot price your job, so below we explain what moves the price. A site visit gives you the actual number.
Standby generator or portable generator?
- A standby generator sits on a pad outside the house, runs on natural gas or propane, and is wired to an automatic transfer switch. When the power goes out, it starts on its own and takes over the circuits it is wired to.
- A portable generator runs on gasoline or another fuel you add, and you start it by hand. Connecting one to your house wiring safely takes a transfer switch or an interlock, plus a generator inlet outside, installed by an electrician. Never plug it into a wall outlet.
Both have to be kept away from the house. The U.S. Consumer Product Safety Commission says to run a portable generator outdoors only, at least 20 feet from the house, with the exhaust facing away from the house. Never run one inside the house or in a garage, even with the doors open. A standby unit is placed according to the manufacturer’s clearances and local code.
Sources: CPSC: Protect your family from carbon monoxide, Mecklenburg County: Generator safety.
Why the transfer switch is not optional
A transfer switch keeps generator power in your house and off the utility lines. Without one, a generator can send power back onto the lines, which is called backfeeding. That puts line workers fixing the outage at risk, and it can damage the generator when utility power returns. Duke Energy advises against connecting a generator directly to a breaker panel, fuse box or meter box because of the hazard to utility line workers, and recommends a licensed electrician for standby generators. Mecklenburg County Code Enforcement says the electrical code requires a transfer switch when a generator is connected to a building’s wiring.
Transfer switches come in a few types:
- Automatic transfer switch (ATS). Used with standby generators. It senses the outage, starts the generator and switches the house over, then switches back when the utility power returns.
- Manual transfer switch or interlock. Common with portable generators. You switch over by hand at the panel.
- Whole-house or selected circuits. A service-rated switch can carry the entire house. A smaller switch carries a chosen set of circuits.
Sources: Duke Energy: Generator safety, Mecklenburg County: Generator safety.
Permits around Rock Hill, Fort Mill and Charlotte
Connecting a generator to the house wiring is electrical work, so it needs a permit and an inspection everywhere in our area. A gas-fired standby generator usually needs a gas permit for the fuel line as well.
- Charlotte and Mecklenburg County: the county says in capital letters that permits and inspections are required to install a generator to the permanent wiring of a building. Mecklenburg County Code Enforcement handles permits for Charlotte, Matthews, Mint Hill and the rest of the county.
- Unincorporated York County, including Lake Wylie: York County Building and Codes requires a permit to install electrical or gas systems. Mechanical, plumbing, electrical and gas permits are issued through the county’s Evolve portal.
- Rock Hill: electrical work in a home must be done by a licensed contractor, who pulls the trade permit.
- Fort Mill and Tega Cay: each town issues its own permits. Owner rules are narrow, so plan on a licensed electrician pulling the electrical permit.
Many neighborhoods also have HOA rules about where outdoor equipment can sit. Check them before you pick a spot.
Sources: Mecklenburg County: Generator safety, York County: Residential permits, City of Rock Hill: Information for property owners, Fort Mill permitting FAQ, Tega Cay permits and inspections.
How sizing works
Generator size is measured in kilowatts (kW). The right size depends on what you want to run at the same time during an outage, not on the size of the house.
- Decide what you need. Some homeowners want the whole house to run as normal. Others want only the essentials: the refrigerator, freezer, some lights, the internet router, a sump or well pump, the furnace fan, and medical equipment.
- List the big loads. Central air conditioning or a heat pump, an electric range, an electric water heater, a dryer, a well pump and an EV charger draw the most. Motors such as AC compressors draw a burst of extra current when they start, and the generator has to handle that.
- Do a load calculation. An electrician adds up the loads from your panel and appliances to find the size that will carry them.
- Consider load management. With an automatic transfer switch, the electrical code requires the generator either to carry everything the switch connects, or to use an automatic load-management system that keeps the load within the generator’s capacity. Load management can let a smaller generator cover more of the house by holding off big loads, such as the AC or the water heater, until there is capacity.
Source: NC Office of State Fire Marshal: Optional standby systems (NEC Article 702).
Fuel: natural gas or propane
- Natural gas comes from the utility line, so you never refuel. It needs a gas service large enough to supply the generator alongside your other gas appliances, and the gas utility may need to check the meter.
- Propane works where there is no natural gas. It needs a tank sized for how long you want to run, set at the distances the propane supplier and code require.
Either way, the fuel line to the generator is gas work with its own permit, done by a licensed gas installer.
What drives the cost
Every job is priced on site, but these are the factors that move the number:
- Generator size. A unit that runs the whole house, including central AC, costs more than one that covers the essentials. Load management can sometimes reduce the size you need.
- Fuel type. Natural gas or propane changes the gas work. A new propane tank, a longer gas line or a larger gas meter all add to the job.
- Transfer switch. An automatic, service-rated switch for the whole house is a bigger part of the job than a switch for a few circuits. Load-management modules add parts and labor.
- Permits and inspections. Electrical and gas permits, inspections, and any HOA approval are part of every installation.
- Installation work at your house. The distance from the generator spot to the meter and the panel, a concrete or composite pad, trenching or conduit, and whether the panel or service needs an upgrade to accept the transfer switch. Our guide to the signs your home needs an electrical panel upgrade explains when that comes up.
- Ongoing care. Standby generators need regular exercise runs and maintenance on the manufacturer’s schedule. Ask what that involves before you buy.
Prices and fees change, and every house is different, so this article does not give price figures. The estimate is what counts.
Get a quote from J&E
We install whole-home standby generators and portable generator hookups for homes in York County and the Charlotte area. If your generator needs a gas line, we can coordinate with a plumber to install it, so the whole project is handled in one job. A recent job was a portable generator connection in Lake Wylie. We are licensed in South Carolina (M110118) and North Carolina (27147-U).
Call (803) 965-8714, Monday to Friday from 8 am to 5 pm, or request an estimate online. We come and look, then you get a quote before any work starts.
Request an estimate · Related service: Specialty Electrical Services
