Home Generator 101: How to Use a Generator Safely and Effectively

We provide the answers to the 10 most common generator questions.

Portable Electric Generator
Getty ImagesDonNichols

When a hurricane, flood, or other natural disaster starts to bear down, people get serious about shopping for a generator in case the power goes out. Here's a tip: Don't wait until you need a backup power supply. Buy a generator now and be ready for anything.

This is a big purchase, however, and there are numerous options for home generators as well as tips you need to know before you try to use one.

How Not To Die: The 5 Generator Safety Tips You Need To Know

Rule 1: Never use a generator indoors.

Don’t use a generator in the garage, even with the door cracked open several inches. For one thing, a prevailing wind blowing into the garage will push the carbon monoxide exhaust from the generator into the house. But even without that, you still risk the fumes infiltrating the house. So don’t do it. Ever. Porches are also off limits as are basements, obviously.

Use a generator outdoors, well away from the house. Run an outdoor-rated extension cord from the machine to the appliances you want to power or use a generator cord to connect to a transfer switch like this one.

The switch prevents the generator from back feeding out of the house and onto the grid, a mistake than can kill a utility worker. See Rule 2. A transfer switch should be installed by a licensed electrician.

Rule 2: Never backfeed.

Backfeeding means to make an extension cord with prongs at both ends. People then take this “hillbilly extension cord” and plug it into the generator on one end and an outlet in the house on the other end. Everything on the same circuit as the outlet is electrified. It’s a bad idea for a number of reasons. But the most deadly reason is that people often forget to throw the main breaker on the service panel and send electricity from the electrified circuit outside the house, onto the grid and through a transformer, which steps up the electricity (instead of stepping it down like it would normally). Now the high-voltage electricity moves out onto the grid. A utility worker coming to repair the grid can be injured or killed by that electricity.

Rule 3: Don’t use a damaged or undersized cord.

People put their money into buying a generator and often neglect the cord. Don’t use a damaged cord with electrical tape all over it and don’t use an undersized cord, especially one designed for indoor use.

Rule 4: Don’t fuel the generator when it’s hot, and don’t keep a gas container near the generator.

Store the fuel inside, like in a shed, not next to the generator. Again, this should be common sense, but people overlook it. A generator cools down quickly once you shut it off, and that’s especially true when the machine is used outside in the winter. All it takes is a small fuel spill on a red hot generator to cause a fire. And the power’s already out, and you have enough problems without having a house fire.

Rule 5: Don’t neglect your fuel supply. Use a fuel stabilizer.

Modern fuel chemically degrades rapidly unless you add fuel stabilizer to it. Bring the stabilizer with you to the gas station and just add it when you fill up the gas tank to ensure it’s properly mixed with the gas.

And while we’re on this topic of fuel, one of the safest and most convenient things you can do for yourself when it comes to fueling a generator is to treat yourself to a decent gas can, especially one with an integral spout.

FAQ: The 10 Most Important Questions About Generators

1. How Big a Generator Should I Get?

We're not talking physical size, but, rather, a generator's electrical capacity. This size depends on the sum of the electrical loads you want to power simultaneously, measured in watts. First, add up all the loads you know you want to be able to run simultaneously. Then, as a precaution, figure out which electrical item in your house requires the most electricity to start its motor and add that to your total. The reason for this is that large items like air conditioners tend to use a lot of juice when they start up—two or three times what they use while they're running. You want to make sure your generator can accommodate that extra electricity requirement; that way, larger items won't overload the system if they start up.

Every generator has two wattage ratings: running wattage and surge wattage. Generators are rated for surge wattage because they should have some excess capacity in case the load you need is temporarily larger than what you've calculated. When you buy a generator, choose the size based on the running wattage and its surge wattage should automatically fall into line with what you need. If you're worried about needing more surge wattage, buy a larger generator.

Ryobi Bluetooth 2,300-Watt Super Quiet Gasoline Powered Digital Inverter Generator
Ryobi homedepot.com

The provides 2,300 starting watts and 1,800 running watts, all of which you can monitor via your phone. For more power check out the which offers 6,500 starting watts and 2,500 continuous watts of power. Both generators are on the quiet side at 57 and 66 dba respectively, and are intended for homeowner use in emergencies as well as year round activities such as camping and tailgating.

2. What Loads Should I Consider Powering with the Generator?

PM contributor Pat Porzio installs generators for a living. He's a mechanical engineer, a plumber and an electrician and is HVAC (Heating, Ventilation and Cooling) manager for Russo Brothers Plumbing in East Hanover, N.J. Here are the circuits he typically powers:

  • First-floor bathroom
  • A couple of lighting circuits
  • Refrigerator
  • Furnace
  • Garage door opener
  • Well pump

    Other loads to consider are a sump pump, a sewage ejector pump or a circuit into which you can plug a window air conditioner.

    3. How Do I Calculate All This?

    Generator manufacturers and retailers post helpful sizing worksheets or wattage calculators on their websites to help you figure it all out; .

    4. Do I Need to Hire an Electrician to Set Up a Generator Safely?

    The safest way to run a generator is to plug it into a piece of electrical equipment called a . This is a combination switch and electrical subpanel. It's wired directly into the house's service panel, and the generator is plugged into it. When you throw its switch, it does two things. First, it disconnects the house from the grid outside. This prevents power from the generator from flowing outside the house, where it can injure or kill a utility worker. Second, it sends power only to house circuits that you've designated. That way, the generator won't be overloaded.

    Unless you're an experienced amateur (you have previous electrical and mechanical training but lack an electrician's license), it's best to have a licensed electrician install a transfer switch.

    5. Can't I Just Plug My Generator into a Wall Outlet?

    No. This is known as backfeeding, and it's blatantly dangerous for a variety of reasons. For instance, if someone forgets to throw the main circuit breaker to electrically isolate the house from the grid, then the generator could send electrical power beyond the house and out onto the grid. When that happens, the electricity you're generating could injure or kill a utility worker who has come to repair the downed grid.

    6. What's the Difference Between a Standby Generator and a Backup Generator?

    A is permanently installed apparatus, much like a compressor for a central air- conditioning system. Its engine runs on natural gas or propane. A is a small, gas-engine generator that you wheel into position outside the house and then plug into the transfer switch. Or it can be connected to electrical loads via heavy-duty extension cords.

    Briggs and Stratton
    Briggs & Stratton 30675A Q6500 Inverter Generator - 6500 Starting Watts QuietPower Series Portable Generator for Home Backup
    Briggs & Stratton amazon.com

    Battery powered generators are another option, albeit an expensive one. Unlike a gas generator, the can be operated indoors and is silent. At 1,500 running and 3,000 surge power, the Goal Zero isn't as powerful as the gas models, but it has more than enough juice to power a few lights, a small fridge, and your personal electronics. Add the solar panel, and you've got unlimited fuel as long as the sun is out.

    7. If It's Raining or Snowing Outside, Can I Put the Generator in the Garage and Run it There, as Long as the Door Stays Open?

    No. Never run a generator inside a house, inside a garage, under a carport, on a porch, inside a screened porch or near an open window. Even with the garage door open, the carbon monoxide (CO) in the generator's exhaust can sicken somebody inside the house or, in the worst case, even kill someone.

    8. What Other Safety Tips Should I Keep in Mind?

    Have working smoke and CO detectors in the house when using a generator.

    Keep the generator at least 10 feet from the house to minimize risks from CO and also the risk of the generator's hot muffler melting vinyl siding.

    Never fuel a generator while it's hot. Remember: "Let it cool before you fuel."

    9. Generators are Loud. What Can Be Done About That?

    Unfortunately, not much. More mechanically advanced generators do a better job than older ones at adjusting engine rpm to their electrical output. This reduces their running speed, which is quieter and conserves fuel. Some home tinkerers are experimenting with putting mufflers from motorcycles and ATVs on their generators. This can be done if you have the requisite metalworking skills. But be warned: In most cases it will void the generator's warranty.

    You have to do your part, too: The simplest way to reduce generator noise is to reduce the electrical load you're imposing on it. Besides, it's unrealistic to think you can maintain your typical lifestyle on a small gas-engine generator outside your house.

    10. Does the Generator Need to Be Grounded?

    Follow the instructions in the owner's manual. If the manual calls for grounding the generator, that's relatively easy to do. One simple way is to run a 12-gauge ground wire from the grounding terminal on the generator to a copper ground rod you've driven into the soil next to the generator. (The generator will have a grounding terminal symbol to help you identify the terminal's location.)

    As an alternative, the manual may ask you to run a ground wire from the generator's grounding terminal to the ground bus inside the house's service panel. As long as you follow the instructions provided in the manual, the generator will be safely grounded.

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