PORTABLE GENERATOR SAFETY TIPS
When the power grid goes down, make sure you’re making all the right choices when you turn to that portable standby electric generator
By Bruce W. Smith
It’s eerily dark in the neighborhood.
The streetlights that normally bring a sense of serenity to our street stand as dark silhouettes against a gray sky and the only sense of life in neighboring houses is the occasional flicker of flashlights and lanterns through the windows.
We are more fortunate. While others are worrying about spoiled food, isolation and roughing it for an indeterminate time, life is near normal in our household.
The lights are on, the refrigerator and freezer are purring along, and the family is gathered around the TV and computers following storm news.
While power outages from the hurricane has put thousands around us in the dark, our portable Honda generator, purring away in the carport, is supplying stand-by power to run our home.
For anyone who lives where the threat of hurricanes, tornadoes, earthquakes, floods, snowstorms and rolling summer blackouts are a part of the seasonal life cycle, portable generators are a welcome step up from camp stoves, lanterns and flashlights.
But you have to do your homework to make the right choice when it comes to buying – and using – a portable generator.
Doing otherwise is sure to lead to disappointment, frustration and even serious injury.
SIZE TO FIT
The first step is to determine your electrical needs. Do you want the generator to power part or all of your home, shop or office?
“A back-up generator is a protective product, so purchase the biggest unit within your budget,” says Donnie Simpson, a certified electrician with 15 years experience taking care of the electrical needs of homeowners from Florida to Texas.
“Having a fundamental understanding of your wattage requirements can prevent you from either overspending or purchasing a generator that’s too small for the job,” said Tom Pernice of Honda Generators product planning.
A good starting point in determining generator size is checking out the Internet. Honda Power Equipment (www.powerequipment.honda.com/generators/wattage-calculator) and Plano Power Equipment (www.planopower.com/honda/generator_guide.html) list common wattages for different home appliances and an easy guide to do the numbers.
But these are just starting points-you need to look at your own home’s electrical appliances and setup.
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 1 kilowatt (1 “kW”).
The power requirements for other household appliances can be found on the operating manual or on the nameplate.
You also need to look for “starting” watts rather than “operating” watts; freezers, refrigerators, microwaves and gas-furnace fans require considerably more wattage to start then they do to run.
Such electrical appliances require as much as four-times the wattage to get started, placing a huge load on the generator.
For example, a refrigerator/freezer may require 800 watts to run, but 2,500 watts to start, while a 1/4-hp furnace fan might take 1,600 watts to startup and 600 watts to run.
Turn on the microwave and it can use 2,800watts to get going and 2,000 watts to continue the cycle.
Once you have a list of items you’d like to run when the power goes down, start adding everything up.
If you want to keep the refrigerator running (2200 starting watts,) a color TV (300 watts,) the computer and four 100-watt light bulbs (400 watts) – you would need a 3000-watt-plus generator.
(Powerhouse’s new Ri-series generators are ideal for powering sensitive electronic equipment.)
Plug in the coffee maker (1700 watts) without turning off something else, and your generator needs jump to 5,000 watts.
Most experts recommend getting a generator 20-25-percent larger than what your calculations show.
This allows for a small margin of error in determining operating loads in a home and keeps the generator running below its maximum load rating for better efficiency.
MAXIMIZING POWER MANAGEMENT
“What homeowners need to understand is there’s a limited supply of electricity on a stand-by power system,” says Jerry Paige, owner of Paige Electric in Long Beach, Mississippi.
“You have to learn how to manage the home’s electrical use with a portable generator. It’s a balancing act; if you want to turn one thing on in the house, then something else must be turned off first or the whole system overloads and shuts down.”
Paige recommends turning on the refrigerator first, followed by the freezer. Once those two appliances are operating, turn on a few lights and any other low-wattage electrical items as needed.
The freezer can be unplugged once it’s chilled down, allowing electrical use to be diverted to, say, a microwave or hotplate.
What most homeowners will find is a generator with 4,500- to 6,000-watt capacity is the minimum required for stand-by power applications. Anything smaller and the investment will be a disappointment when the power goes out.
An even greater consideration-and one many homeowners fail to recognize-is safety issue when it comes to the proper use and installation of a portable generator.
”There are a lot of homeowners who buy a generator and just plug it into the nearest outlet without thinking about the deadly situation they just put themselves and others in,” warns Paige.
When you plug an extension cord from the generator into the wall socket, you are supplying power to the house – and to the outside powerlines that feed the house.
So anyone in contact with those powerlines is now at risk of being electrocuted.
The local utility company uses a step-down transformer to drop incoming voltage to the home from 17,500-volts to 220. What homeowners don’t realize is the transformer can function just as easily in the other direction.
Hence the need for what is commonly called a “transfer switch.” A transfer switch is a manual three-position switching device that allows power to be channeled to the home’s electrical system either from the utility company power lines or from the generator-not both.
“A transfer switch is a key component of any home standby setup, as it simplifies the distribution of power to appropriate areas of the home, and minimizes the risk of shock to those repairing power lines,” said Clay Yeatman, model engineer for Honda Generators.
Plugging a generator directly into a wall socket instead of utilizing a transfer switch sets up several potentially deadly scenarios:
- a short-circuit and electrical fire in the home’s wiring when power is restored;
- a system short-circuit in the generator causing it to catch fire or explode when power is restored;
- and the possible electrocution of linemen working to restore power in your area.
“Placing power company workers harm’s way is something few, if any, homeowners think about,” says Simpson.
“The use of a double-throw (on-off-on) transfer switch is critical for home generator use. It protects everyone concerned-from the homeowner’s family to the power company personnel working to restore power-from ‘back-feeding’ the power grid.”
INSTALLING A TRANSFER SWITCH
The potential for electrocuting an unsuspecting person happens the instant the generator connects to the home’s electrical csystem.
The local utility company uses a step-down transformer to drop incoming voltage to the home from 17,500-volts to 220.
What homeowners don’t realize is the transformer can function just as easily in the other direction.
When you plug a home generator directly into the house circuit without using a transfer switch, that current feeds back to the power company’s transformer.
In turn, the transformer steps the generator’s voltage up to 17,500 volts and feeds it on into the power lines.
This stepped up voltage, backfeeding through the utility lines from the home’s stand-by generator, is more than enough to electrocute anyone coming in contact with lines they thought were dead.
A double-throw transfer switch, which isolates the utility company’s power from that supplied by the generator-and vise versa, prevents backfeeding from occurring.
That is why the use of a transfer switch is required by the National Electric Code when connecting an auxiliary power source (generator) to an existing system (home).
Buying a portable stand-by generator for home, cabin, or office use can range from $300 to $4,500 depending on make, output, design and amenities.
The bigger the output, the more sophisticated the design, and the more features a generator provides, the higher the price.
You must also factor in the cost of a transfer switch ($150 for a 30-ampere model designed for light-duty home applications),
a professional installation ($200-$400 depending on the location of your service meter box), and the heavy-duty power cable ($75-$125) that is required to connect the generator to the transfer switch box.
“We recommend using a water-resistant, Seoprene-covered 10/4 AWG cable with marine-style four-pin twist-lock plugs,” says Paige, who made up the 75-foot extension cable that runs from carport to the transfer switch box for our installation.
“Not only can it safely carry the heavy electrical load, it also provides protection from both the elements and abrasion.”
USING EXTENSION CABLES
Some generator users mistakenly think they can run a regular extension cord from their generator to a wall outlet in the home. Such a practice is a recipe for disaster.
According to Reliance Controls, the world’s leading supplier of transfer switches for portable generators, “This can be done as long as no connection exists between the generator and the utility and the appliance and the utility, i.e. there is no chance of back-feeding the utility.”
Making that direct connection from the generator to the house circuit with an extension cord sends power back to the service panel and on into the power lines.
It also energizes just one circuit in the house, where using a transfer switch connection energize the sub panel and related circuits.
Another safety factor is the typical extension cord is not heavy enough to handle the current or load placed on it by the larger portable generators.
The end result can be overheating of the extension cord and eventual short-circuiting of the system, potentially damaging both home and generator.
NEW HOME WIRING
If you are building a new home, consider having the contractor install a sub-panel that is already setup for stand-by power.
This saves you money because there’s usually no additional installation labor costs and the generator-ready panel eliminates the need for an additional transfer switch box.
Electrical parts suppliers, such as Square “D” and Reliance, offer sub-panels that already have the generator plug-in and transfer switch pre-wired into the unit.
Generator-ready service panels run $200-$300 more than standard units, but the labor and convenience factor more than make up for the cost difference.
Having your home’s electrical system set-up for stand-by power from a portable generator also adds to its resale value-especially in areas where power outages are a common occurrence.
GENERATOR BEST BUYS
The best time to shop is during the Fall and Spring when inventories are high and demand low. You can also save money by shopping on the Internet.
Most of today’s portable generators are powered by diesel or four-stroke gasoline engines, which, under maximum load, will burn up to a gallon of fuel per hour.
Fuel tanks are generally large enough to provide 5-7 hours of uninterrupted power.
“Factors homeowners should consider are buying a generator like yours that is going to be durable for the long haul, quite running, efficient in its operation, and provide ‘over-current’ protection,” Simpson said during the installation of the transfer switch so we could use an older Honda EX5500K2A for our home’s stand-by power.
Honda generators use state-of-the-art four-stroke engine design to minimize fuel use and noise while maximizing generator output. Four-strokes are also very low maintenance, adding to long-term reliability.
Top-of-the-line models, such as the Honda and Powerhouse generators, also provide such niceties as electric key start, circuit breakers with automatic over-load protection.
Just as important, they provide “clean” electrical power for computers and other sensitive electronic equipment, low-oil warning/protection, and automatic idle/throttle that adjusts the generator to the loads, maximizing efficiency.
Which brand and model of generator you choose depends entirely on needs and budget.
Whatever the choice, having a stand-by system in place is a nice security blanket that more than pays for itself when the power goes down.—Bruce W. Smith
About the author: Bruce W. Smith is a full-time, nationally known automotive, outdoors, marine and RV writer/editor/photographer with more than 30 years experience. Smith is currently the editor of Randall-Reilly’s ProPickup magazine. He lives in Long Beach, MS, and has spent his share of time with portable generators supplying power needs thanks to enduring the wrath of multiple Gulf Coast hurricanes including Hurricane Katrina.