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Transfer of Power

A portable gas-fired generator and a transfer switch will keep your house up and running while your neighbors remain in the dark.

Photo by Ron Chapple

A bright flash of lightning, a loud clap of thunder, then suddenly your home is plunged into total darkness. The electricity is out, the silence is deafening, and all you can do is sit and wait.

Sound familiar? Power outages are unavoidable and indiscriminate. Fortunately, in most cases, the electricity is restored in less than an hour. But if you live in an area where power outages occur often or if they last for prolonged periods, losing power is much more than just an occasional inconvenience.

An outage of more than a few hours can spoil refrigerated foods and cause frozen items to thaw. In a very short time, a house can become bitterly cold in winter and suffocatingly hot during

during summer; both are potentially dangerous conditions for infants, the elderly, and the infirm. And for a household that relies on a well pump, a loss of electricity means no water for drinking, bathing, or flushing the toilet.

Perhaps the worst part is that a power outage leaves you feeling helpless and vulnerable, especially when it strikes at night. But there is a way to take charge of the situation and keep much of your home up and running until the power is restored. The most practical way to beat the blackout blues is to create your own power with a portable gasoline-fired generator. The next step is to hook the generator directly to the circuits in your home with an electrical-transfer switch.

Power Options

Gasoline-powered generators are rated according to the number of watts of electricity they produce. The most popular size for home-emergency use is a 5,000W unit ($600 to $2,000). Smaller, more affordable generators are available, but they can only handle one or two small appliances. A 5,000W unit is large enough to power several circuits, including most refrigerators and freezers, and it will run up to 10 to 12 hours on its 7-gallon tank of gas.

On the downside, these generators are heavy and noisy compared with the type you might have used to run a small power tool. Most 5,000W generators weigh between 150 and 200 lbs., making them virtually impossible to move by yourself. Some manufacturers sell a bolt-on wheel kit (starting at about $40) that makes it much easier to move the unit.

The most common way to use a portable generator is to place it outdoors, then run an extension cord through an open window or door to the chosen appliance. (Generators produce deadly carbon monoxide gas, so you should run your unit only outdoors and never in an enclosed space, including a garage or basement.) That approach works well, but it's very limited because you can only plug in one or two items. Plus, the extension cord can't be plugged into a furnace, well pump, or ceiling-light fixture.

<p>A six-circuit transfer switch is designed for a 5,000W generator, like this Campbell Hausfeld unit (Model GN5031, $899).</p>

A six-circuit transfer switch is designed for a 5,000W generator, like this Campbell Hausfeld unit (Model GN5031, $899).

Photos courtesy of Campbell Hausfeld

Power Switch

About 20 years ago, electrical-sales engineer Paul Schnackenberg, founder of Gen-Tran Corporation, invented an electrical device called a transfer switch. It allows homeowners to use a portable generator to safely run several electrical circuits, including a furnace or well pump. The transfer switch is installed beside the main electrical panel, then it's connected to the appliances and circuits you think you'll want running during a blackout.

When the power goes out, you simply crank up the generator and run an extension cord from it to the transfer switch. Better yet, you can eliminate the cord by installing a power inlet box ($52) on the exterior of the house and plugging the generator into it.

Once the generator is running, you can pick and choose which appliances and circuits you want to use simply by flipping the switches on the transfer switch. It's important to keep track of what's being powered because the transfer switch typically is wired into more circuits than the generator can handle all at once. Plus, overloading the circuits can shorten the life of an appliance and burn out its motor. Carefully read the owner's manual that comes with the generator. Some manufacturers recommend operating the unit at no more than 80 percent of full capacity.

It's also important to match the transfer switch to the generator. For example, Gen-Tran makes several transfer switches and each has a maximum-wattage capacity. Its most popular unit is the six-circuit switch (Model 20216, about $260), designed for use with a 5,000W generator. For a home that requires greater capacity, Gen-Tran makes a 10-circuit switch (Model 302110, about $390) that runs off a 7,500W generator.

A transfer switch is relatively easy to install, but for safety's sake, we strongly recommend that you call in a licensed electrician. A typical installation will only take about an hour. Our job was a bit more complicated because it included the installation of a power inlet box. It took the electrician almost three hours and cost about $400. Still, it's an investment that will be fully appreciated the next time the power goes out.

<p>This 4,800W Makita generator ($2,229) has four different receptacles and push-button electric starting.</p>

This 4,800W Makita generator ($2,229) has four different receptacles and push-button electric starting.

Photos courtesy of Makita

How Much Juice Do You Need to Produce?

The chart below shows how many watts of electricity it takes to run various household appliances. Also listed are the number of watts needed to start up appliances that have motors. When using any generator for emergency power, be sure that the total running watts and starting watts of all the appliances

being used at one time doesn't exceed the design maximum.

However, the total number of watts (running and starting) hooked up to the transfer switch can exceed this limit; you just won't be able to use all the appliances at the same time. For example, powering a 3,000W electric water heater with a 5,000W generator leaves you barely enough juice to run your coffeemaker. And remember, an 800W refrigerator will require an additional 2,300 watts each time the compressor kicks on.

Coffeemaker: 1,750 running watts, add 0 watts for starting

Freezer: 500 running watts, add 750 watts for starting

Furnace (1/4-hp fan): 600 running watts, add 1,000 watts for starting

Furnace (1/2-hp fan): 875 running watts, add 2,350 watts for starting

Lights: running watts are printed on bulb, add 0 watts for starting

Microwave Oven: 600-1,500 running watts, add 0 watts for starting

Refrigerator: 800 running watts, add 2,300 watts for starting

Room Air Conditioner: 2,000 running watts, add 6,000 watts for starting

Security System: 100-500 running watts, add 0 watts for starting

Space Heater: 1,100-1,500 running watts, add 0 watts for starting

Sump Pump: 800-1,050 running watts, add 1,300-2,500 watts for starting

TV/VCR: 400 running watts, add 0 watts for starting

Water Heater (electric): 3,000 running watts, add 3,000 watts for starting

Water Heater (gas): 500 running watts, add 1,500 watts for starting

Well Pump (1/2 hp): 1,000 running watts, add 2,100 watts for starting

<p>This powerful 7,500W Generac unit ($1,899) creates enough juice to power a 10-circuit transfer switch.</p>

This powerful 7,500W Generac unit ($1,899) creates enough juice to power a 10-circuit transfer switch.

Photos courtesy of Generac

When Only Full Power Will Do

If your neighborhood seems to be the last to have its power restored or you just like the idea of having all circuits available without even venturing out in inclement weather to start your generator, you might want to consider getting a whole-house, standby power unit installed.

Standby generators offer the ultimate in blackout protection by supplying electricity to your entire house, not just to a few selected circuits. These personal power plants come in various sizes up to 40,000W, and run on natural gas, propane, or diesel fuel. They get installed outside on a concrete slab or pier blocks and are wired through a transfer switch to the main electrical panel. When the power goes out, there's a slight delay of 15 to 20 seconds, then the generator automatically kicks on and continues running until power is restored.

Of course, you pay a premium for all this convenience and peace of mind. The average-size home will require a 12,000W to 15,000W generator, which costs $6,000 to $8,000. Installation can easily run another $2,000.

For specific information regarding generator size and installation costs, consult a local electrician or check out

And, finally, the installation of a whole-house generator must be specifically designed for your home. Disregard any price quote given by an electrician who hasn't personally inspected your electrical system and site.