How to Hook Up Generator to House Without Burning Down Your Neighborhood

I've been connecting generators to houses for about fifteen years now, and let me tell you, the number of times I've seen people nearly electrocute themselves or fry their entire electrical panel would make your hair stand on end. Last winter, during that brutal ice storm that knocked out power for three days, my neighbor Jerry decided he'd just run extension cords from his generator through the windows. By day two, he had melted outlets and a very expensive electrician's bill.

The thing about generators is they're simultaneously simple and complex. At their core, they're just engines that spin magnets to create electricity. But connecting that spinning magnetic field to your home's electrical system? That's where people get into trouble.

The Transfer Switch: Your Home's New Best Friend

You absolutely need a transfer switch. I cannot stress this enough. Without one, you're playing Russian roulette with your home's electrical system and potentially the lives of utility workers. A transfer switch is essentially a specialized electrical panel that prevents your generator from backfeeding electricity into the power lines.

I learned this lesson the hard way back in 2008. A buddy of mine thought he could save a few hundred bucks by skipping the transfer switch and just flipping his main breaker off. What he didn't realize was that his generator was sending power back through the transformer, stepping it up to thousands of volts on the utility lines. The power company showed up at his door with some very stern words and a hefty fine.

Transfer switches come in two main flavors: manual and automatic. Manual switches require you to physically flip the switch when the power goes out. They're cheaper, usually running between $300-$800 for the switch itself. Automatic switches detect when the power fails and switch over without any intervention. These beauties will set you back $2,000-$4,000, but if you've got medical equipment or just hate stumbling around in the dark, they're worth every penny.

Sizing Your Generator (Or: How I Learned to Stop Worrying and Love Watts)

Here's where most people mess up royally. They buy a generator based on what's on sale at the big box store, not what their house actually needs. You need to calculate your home's electrical load, and this isn't as simple as adding up the wattage on your appliance labels.

Motors – like those in your refrigerator, air conditioner, or well pump – draw significantly more power when starting up than when running. We call this surge wattage or starting watts. Your refrigerator might run on 700 watts, but it needs 2,100 watts to start. Miss this calculation, and you'll be wondering why your generator keeps tripping every time the fridge compressor kicks on.

I usually tell people to make a list of what they absolutely need during an outage. For most folks, that's the refrigerator, some lights, maybe the furnace blower, and a few outlets for charging phones. That typically requires a 5,000-7,500 watt generator. Want to run your central air? Now we're talking 10,000 watts minimum, and probably more like 15,000-20,000 for a larger home.

The Installation Dance

Installing a generator connection isn't a weekend warrior project unless you're already comfortable working with electrical panels. I've seen too many DIY disasters to recommend it. But understanding the process helps you communicate with your electrician and avoid getting ripped off.

First, you need to decide where your generator will live during outages. It needs to be at least 10 feet from any doors, windows, or vents – carbon monoxide is a silent killer. I've seen people put generators in garages with the door open, thinking that's enough ventilation. It's not. Ever. A family in my town nearly died this way during Hurricane Sandy.

The inlet box gets mounted on your home's exterior wall. This is where you'll plug in the heavy-duty cable that runs from your generator. The cable itself needs to be rated for the amperage your generator produces – typically 30 or 50 amps for residential setups. Don't cheap out here. I once saw someone use a dryer cord because "it looked the same." It melted within an hour.

Your electrician will run wiring from the inlet box to the transfer switch, which gets installed next to your main electrical panel. If you've got a newer home with a 200-amp service, installation is usually straightforward. Older homes with 100-amp service or funky panel configurations can get complicated fast.

Interlock Kits: The Budget Option That Isn't Always Cheaper

Some folks ask about interlock kits as a cheaper alternative to transfer switches. An interlock kit is a sliding metal plate that prevents your main breaker and generator breaker from being on simultaneously. They're legal in many areas and cost about $150-$300.

But here's the rub: you still need a generator inlet box, the proper gauge wire run to your panel, and a new breaker installed. By the time you pay an electrician for all that work, you're often within spitting distance of a manual transfer switch price. Plus, with an interlock, you're powering your entire panel, which means you need to manually turn off breakers for circuits you don't want to power. Forget to turn off your central air breaker, and your 7,500-watt generator will stall faster than a teenager learning stick shift.

Portable vs. Standby: The Eternal Debate

Portable generators are what most people think of – those units on wheels that you drag out of the garage when the power fails. They run on gasoline, propane, or sometimes both (dual fuel). They're cheaper upfront, usually $500-$3,000 for a decent residential unit.

But let's talk about the reality of portable generators. During extended outages, you're constantly hunting for gas. Gas stations need electricity to pump fuel, so when the power's out widespread, good luck finding an open station. I keep 20 gallons of stabilized gas on hand, which gives me about two days of runtime. Then I'm driving 30 miles to find more.

Standby generators are permanently installed outside your home, connected to your natural gas line or a large propane tank. They start automatically when the power fails. No dragging equipment around in a storm, no gas runs, no extension cords. The downside? They start at about $3,000 for a small unit, and installation typically runs another $3,000-$5,000.

I finally bit the bullet and installed a standby generator after the 2011 Halloween nor'easter. We lost power for nine days. NINE DAYS. I spent more on gas for my portable generator than I would have on a year of natural gas for a standby unit.

The Permit Question Nobody Wants to Ask

Yes, you need a permit. I know, I know – permits are a pain. But here's why you should care: insurance. If you have an electrical fire and your insurance company discovers you did unpermitted electrical work, they can deny your claim. I've seen it happen. A $150 permit suddenly looks pretty cheap compared to rebuilding your house out of pocket.

Most jurisdictions require a permit for installing a transfer switch or interlock kit. The inspector will check that your installation meets code, which varies by location but generally follows the National Electrical Code. They'll verify proper grounding, appropriate wire gauges, and correct breaker sizing.

Maintenance: The Unsexy Part That Matters Most

Generators are engines, and engines need love. I run my portable generator monthly, even in summer when storms are less likely. Stabilized gas goes bad after about a year, so I rotate my supply. Oil changes every 50-100 hours of runtime, depending on your manual's specifications.

For standby generators, most manufacturers recommend weekly self-tests. The unit runs for about 15 minutes to circulate oil and charge the battery. Annual professional maintenance runs about $200-$400 but can prevent that sinking feeling when you need power and nothing happens.

My Final Thoughts After Too Many Dark Nights

Connecting a generator to your house isn't rocket science, but it's not something to approach casually either. The consequences of doing it wrong range from expensive to deadly. Hire a licensed electrician, get the proper permits, and size your equipment correctly.

I've learned that the best generator setup is the one that matches your actual needs and budget, not what your neighbor has or what some salesperson pushes. My elderly parents need automatic everything because Dad can't pull-start a generator anymore. My brother the prepper has a massive diesel unit that could power half the neighborhood. Me? I've got a reasonable standby unit that keeps the essentials running without breaking the bank.

Remember Jerry from the beginning? He eventually hired an electrician and got a proper transfer switch installed. During the last outage, he was the one making coffee for the neighborhood while everyone else was eating cold cereal. Sometimes learning the hard way leads to doing things the right way.

The peace of mind that comes from knowing you can safely power your home during an outage? That's worth more than any amount of money saved by cutting corners. Trust me on this one.

Authoritative Sources:

National Fire Protection Association. NFPA 70: National Electrical Code. 2020 ed., National Fire Protection Association, 2019.

Occupational Safety and Health Administration. "Using Portable Generators Safely." OSHA Fact Sheet, U.S. Department of Labor, 2017, www.osha.gov/sites/default/files/publications/OSHA3286.pdf.

Consumer Product Safety Commission. "Portable Generators and Carbon Monoxide." CPSC Safety Alert, U.S. Consumer Product Safety Commission, 2021, www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center/Portable-Generators.

Electrical Safety Foundation International. "Generator Safety." ESFI Consumer Resources, Electrical Safety Foundation International, 2022, www.esfi.org/resource/generator-safety-418.

U.S. Department of Energy. "Installing and Maintaining a Small Renewable Energy System." Energy Saver, U.S. Department of Energy, 2021, www.energy.gov/energysaver/installing-and-maintaining-small-renewable-energy-system.