How to Select and Operate a Portable Generator

When severe weather strikes power outages often follow. Depending on where you live you may have experiences prolonged power outages lasting 12 or more hours. Many homeowners opt for purchasing a small portable generator to power small appliances and lights during an outage.

Proper use and care for a portable generator is important to prevent injury, fire, or even death. Connecting a portable power generator to your home's main wiring panel can be dangerous if you don't follow the manufacturer’s wiring diagrams and instructions. The safest way to connect a portable power generator to your main panel is to have a transfer switch installed by a licensed electrical contractor and have the system tested and inspected by your local building inspector and fire marshal.

A transfer switch moves the power from the power lines of the utility company to the power from your portable generator. They can be automatic if you have a permanently installed stand-by generator or manual transfer switches that can be used with a portable generator. A transfer switch with circuit breakers may cost around $650 to $800, not including installation.

Typical Electrical Connections

Safety Considerations

When you're connecting a portable generator to your home’s electrical system you must never plug it directly into any standard household outlet. This could energize utility power lines and cause injury or death to utility personnel or neighbors. This is called “backfeeding” and it also bypasses some of the household circuit protection devices.

Each individual appliance should be connected directly to the generator, without overloading the generator. Or, use a heavy-duty, outdoor rated extension cord that is rated (in watts or amps) for the total electrical load of all the connected appliances and the generator output. Check that the entire cord is free of cuts or tears and that the plug has three prongs, especially a grounding pin.

Your generator should never be operated indoors or in any enclosed area. The carbon monoxide (CO) build up can be deadly and unnoticeable until it's too late. It should operate out of doors in an area that is dry and well ventilated. When you use a portable generator, remember that you cannot smell or see CO. Even if you cannot smell exhaust fumes, you may still be exposed to CO. If you start to feel sick, dizzy or weak while using a portable generator, get to fresh air immediately. The CO from portable generators can quickly lead to full incapacitation and death. If you experience serious symptoms, get medical attention immediately. Tell the medical staff that you suspect CO poisoning. If you experienced symptoms while indoors have someone call the fire department to determine when it is safe to reenter the building.

Follow these safety tips to protect against CO poisoning:

Never use a portable generator indoors, including in homes, garages, basements, crawl spaces and other enclosed or partially enclosed areas, even with ventilation. Opening doors and windows or using fans does not prevent CO buildup.

Never store fuel for your generator in your house. Gasoline, diesel, and propane should be stored outside of living areas in properly labeled safety containers. Do not store them near a fuel-burning appliance, such as a water heater or furnace. If the fuel is spilled or the container is not sealed properly, vapors from the fuel can travel along the ground and be ignited by the appliance’s pilot light or by arcs from electric switches in the appliance.

Before refueling the generator, turn it off and let it cool down. Gasoline spilled on hot engine parts could ignite.

Buying Tips

You may want to research magazines or Consumer Reports for the best rated generator in your price range. Look for ratings from Good Housekeeping and check that it is UL listed or certified from the Canadian Standards Association (CSA).

Portable generators can come equipped with wheels and folding handles for easy moving and storage. Look for safety features like emergency shutoffs, fuel gauge, battery gauge, low-oil warning light, over temperature warning light, electronic ignition, as well as the power capacity.

Mid-sized generators have more power and more functions such as automatic voltage regulation. Whichever generator you purchase look for the longest warranty available.

Generator Accessories

The purpose behind a cover for a portable generator is to protect it from inclement weather such as rain, wind, ice and snow, as well as pests and falling debris from trees.

Depending on the location of your portable generator you may also want to purchase cord covers. Many people try to use duct tape instead of buying a cover for their portable generator cord. This can damage interior floors and become a trip hazard when the tape comes loose. Cord covers for your portable generator are your most efficient and safest choice. They have a slit on the bottom of the cover where you insert the cord. Cord covers can be cut to length with a utility knife and they typically come in 6 or 15 foot lengths.

Fuels

Portable generators can be built to run on various fuels such as gasoline, propane, diesel, and natural gas. Some models are bi- or tri-fuel where 2 or 3 different fuels can be used if you run out of one and have to switch to another fuel.

Propane GeneratorMost portable propane generators are generator can run the lights and one or two small appliances. You will spend 40-50 percent less for each hour of operation with a portable propane generator than with a gasoline generator. The propane can be supplied from a separate tank or from a larger tank if you use propane to cook and heat your home.

3500W Propane Generator

You can expect to pay around $500 for a 3500W propane generator. A 6000W generator will cost around $900. The most common sizes are 3.5kw, 6kw, 12kw or 13kw.

Diesel GeneratorDiesel generators are typically permanently installed, but there are portable models available. These are usually a larger capacity, 5500W or 6500W with costs between $1,000 and $1,400. Diesel generators will usually run longer, but may be difficult to start in extremely cold weather.

6500W Diesel Generator

Gasoline Generator Probably the most popular type of generator, gasoline generators are usually less expensive than propane or diesel, but they may require slightly more maintenance. Many models have reduced emissions, referred to as California models. Power ratings can be as low as 600W up to 10,000W. Costs can be anywhere from $200 up to $900.

Gasoline Portable Generator

Power Consumption of Appliances

Before you try to power up your entire house, you may want to prioritize your electrical use and have these circuits installed on your transfer switch. Remember you can always unplug or turn off any unnecessary electrical equipment when the generator is running to conserve fuel. Most generators list their run times at full and half loads.

Most appliances and electronics have the power consumption listed on a label somewhere on the device, but here are power draws for common household appliances in watts:

• Coffee maker = 900–1200

• Clothes washer = 350–500

• Clothes dryer = 1800–5000

• Dishwasher = 1200–2400

• Dehumidifier = 785

• Electric blanket = 60 / 100

• Fans

    • Ceiling = 65–175

    • Window = 55–250

    • Furnace = 750

    • Whole house = 240–750

• Hair dryer = 1200–1875

• Heater (portable) = 750–1500

• Microwave oven = 750–1100

• Personal computer

    • CPU - awake / asleep = 120 / 30 or less

    • Monitor - awake / asleep = 150 / 30 or less

    • Laptop = 50

• Radio = 70–400

• Refrigerator (frost-free, 16 cubic feet) = 725

• Televisions

    • 19" = 65–110

    • 27" = 113

    • 36" = 133

    • Flat screen = 120

• Toaster = 800–1400

• Toaster oven = 1225

• VCR/DVD = 20–25

• Vacuum cleaner = 1000–1440

• Water heater (40 gallon) = 4500–5500

• Water pump = 250–1100

(Source: U.S. Department of Energy http://www.energysavers.gov/your_home/appliances/index.cfm/mytopic=10040 )