Electricity, once a luxury, is
now essential. To beat weather-related electrical outages, many households and
businesses are investigating back-up power generators for use in an emergency.
Generators are widely available in a range of sizes and configurations. Some come equipped with gasoline, diesel or propane engines. Others operate from the power takeoff attachment found on many tractors. These devices all have one thing in common—they produce electricity at levels high enough to cause injury, death and property damage. That does not mean they should not be used. But, like any other electrical equipment, they must be correctly sized and properly installed. Generators are rated by the wattage they produce—usually expressed in kilowatts—and are sized according to the loads they need to serve.
To determine the size of the
generator needed, total the rated watts of the appliances and fixtures you will
want to operate during an outage. Some loads are easy to determine—a
100-watt light bulb, for example, uses 100 watts. Ten 100-watt bulbs would
require 1,000 watts or one kilowatt. The power requirements for appliances are
often provided in the operating manual.
While the power needs of
individual appliances vary, those that produce heat or use large motors tend to
require higher wattage. Power need for motors, such as those powering well
pumps, furnace fans and refrigerators and freezers are more difficult to
determine. Electric motors require more current when starting than they do in
continuous operation. Without sufficient starting power, motors may overheat,
burn out or trip the generator's circuit breaker.
In most instances, it will not
be economical or practical to try to supply the entire usual electrical needs of
a home or business from a standby generator. Instead, only selected, essential
loads should be served from the generator to serve the minimum possible heating,
refrigeration, water supply and lighting loads. More important than sizing is
correct installation. Auxiliary power sources must be completely isolated from
the cooperative's lines attached to your meter to avoid backfeeding into your
cooperative's system.
During an outage, line crews
trying to restore power—or anyone who contacts a downed line—could be
seriously injured or killed by backfeed from an improperly installed generator.
A special switch is used to transfer a building's wiring from normal to a
standby power source. The device—called a double-throw switch—is
designed to prevent a generator's output from backfeeding through the
cooperative's transformers and lines. The switch makes it impossible to connect
the main power source to the generator. The use of a double-throw switch is
required the National Electric Code when connecting an auxiliary power
source to an existing system.
If you are considering
installing an emergency back-up generator, contact a generator equipment dealer
and a licensed electrician. They can help you select a system that will safely
provide temporary power when needed without creating additional problems or
hazards.
Every year, people are killed
by carbon monoxide poisoning caused by operating
generators within their homes or near a window or door. Please be safe, always
operate generators outside with adequate ventilation.
A double-throw switch ensures that electricity from your generator does not backfeed onto your cooperative's power lines where it can cause injury or death to cooperative line personnel repairing lines or any person who happens to be in contact with a power line when you start your generator.
