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Can a Generator Damage Appliances?

OnGuard Generators technician with circuit list
Many people wonder if generators can damage ordinary household appliances such as refrigerators, HVAC systems, washing machines and ovens.  While any kind of appliance can potentially be damaged by a backup generator, the risk of appliance damage can be greatly reduced or eliminated with the selection of the right sized generator for your home or business and operating it safely and in line with the owner’s manual.

The Importance of Proper Generator Selection.

Remember that in selecting a generator, you can choose between a smaller portable generator or a larger permanent standby generator.  While each delivers power to your home or business in the event of a grid failure, a portable generator is designed to power only a select handful of appliances while a permanent standby generator is designed to power most, if not all, appliances within your home or business.
Choosing the proper size generator in terms of wattage output will eliminate the risk of overloading your generator.  Overloading your generator can not only damage the generator itself but can also cause appliances connected to the generator to be damaged.
Therefore, the selection of the right generator is very important, not just for providing enough power to the appliances you want to use during a power outage but also for protecting your appliances from damage.  Key decisions as you begin to shop for a generator will be the generator size required and the specific kind of generator you need.  Both decisions will factor into protecting all of your appliances, ranging from the ordinary (refrigerator, lights, space heater, power tools) to the most sensitive (computers, stereo, TV sets and smart phones).
With regard to size, you will need to buy a generator big enough to handle the load it is called on to deliver.  If you overload your generator, you can not only damage the generator itself but also appliances connected to the generator.  So, eliminating the risk of appliance damage from a generator can largely be eliminated upfront when you set out to purchase your generator.
As you begin to shop for a generator, you will first need to determine what items you want to operate during a power outage.  If your list contains a relatively smaller number of items that you consider “essential” such as a refrigerator, space heater, microwave oven and lights, then a portable generator should be sufficient.  However, if your list includes most if not all appliances in your home or business, then a more powerful permanent standby generator is the way to go.
Once you have made the basic decision between a portable generator or a permanent standby generator, you will then have to determine the total wattage required by appliances and electronics on your list.  In making this calculation, it is very important to be accurate so as to eliminate the possibility of generator overload.  As you go about this, remember that wattage requirements for some electrical appliances include both “starting” watts and “running” watts.  Both need to be factored in for each appliance you plan on running with your generator.   As an example, a water well pump can can have nearly 1,500 starting watts and only 600 running watts.  After you determine your total wattage requirement, it is advisable to increase it by a factor of 1.5x-2x so that you have a “cushion” that will protect your system from an overload situation.
With your total wattage requirement in hand, you can now start shopping for specific generator brands and models that will comfortably handle your load.  As a general rule, portable generators are available in a range of 1,000-4,000 watts and permanent standby generators are available in a range of 5,000 to 50,000 watts.  Again, by selecting a generator whose power capacity comfortably exceeds the load you will place on it, you have addressed the major risk factor in having your everyday appliances damaged by your generator.
Remember that portable generators are typically bought at your local “big box” home improvement store and are operated manually while permanent standby generators are purchased from a licensed electrician, who will also install and maintain your system.  In other words, you are pretty much on your own in selecting a portable generator that is the proper size, whereas with a large permanent standby system, you can lean on the expertise of your electrician in selecting a system that will adequately meet your power needs and keep your appliances safe.
A wrinkle in the appliance safety question comes in the form of newer electronic products that are built with sensitive microprocessors (computers, laptops, TV’s, iPhones, etc.).  Portable generators on the market today do a good job of generating electricity for basic appliances like refrigerators, power tools, lights and sump pumps without the risk of damaging these appliances (provided that you do not overload your unit). These “everyday” appliances typically do not contain sensitive microprocessors found in more “sophisticated” electronic products.  Many portable generators on the market today produce what’s called “dirty power” that can include voltage fluctuations and these fluctuations pose little risk to appliances that do not contain microprocessors.
With the growing number of microprocessor-based consumer electronic products being used, a new technology was developed for portable generators called inverter technology, which turns “dirty” power into “smoother, cleaner” AC power that is free from voltage spikes and drops, protecting the most sensitive electronics devices.  Again, while most portable generators pose minimal risk to most standard appliances, a portable generator with inverter technology eliminates the risk of damage to your more sensitive electronics. So, if you plan on using your generator to deliver power to more sensitive electronic products, it is a good idea to consider a portable generator with inverter technology.  You should be aware that in addition to protecting your electronics, inverter generators have other advantages over traditional portable generators as they are smaller, lighter, operate more quietly and tend to be more fuel efficient. The primary drawback of inverter generators is that they cost more than traditional portables.
If you go the route of a larger permanent standby generator system, you should know that virtually all large permanent standby generators today are built with technology that produces “clean” power that is equivalent to what you receive from your utility.  This clean, smooth power will not only work well with your everyday appliances but will also protect your most sensitive electronic appliances.
Proper Generator Operation Can Also Reduce the Risk of Damage to Appliances
As mentioned above, all portable generators are operated manually by the homeowner or business owner.  For this reason, it is very important that portable generators are operated safely and properly so as to reduce or eliminate the risk of damage to your appliances.  Always start with the “cardinal rule” of not overloading your generator with too many appliances as you can damage both your generator and your appliances.  Beyond that, the use of surge protecting power strips can go a long way in protecting your appliances from damage caused by power surges.  There are other common safety precautions that will be covered in your Owner’s Manual and some of the more important ones include: grounding your generator is properly grounded, don’t plug appliances into your generator before starting it, using properly rated outdoor type extension cords when connecting appliances to your generator, always use a portable generator outdoors in a well-ventilated area to eliminate the risk of carbon monoxide poisoning and never re-fuel a generator that is hot from running as it presents a fire and explosion risk.  Always consult your Owners Manual before using your generator.
Because permanent standby generators operate automatically without human intervention, there is much less risk of damage to appliances from operator error.  When these systems detect a loss of power from the utility, a transfer switch disengages your home or business from the utility and hands over the responsibility of providing electricity to the generator.  The risk of appliance damage from overload should have been eliminated with the selection of the proper sized generator in consultation with your electrician.  Recall that these larger systems are installed by a licensed electrician, who makes sure upfront that they are the proper size relative to the load and that they protect all of your appliances, including those with sensitive microprocessors.  And with respect to sensitive microprocessor-based electronics, virtually all standby generators have “smooth, clean” power technology  that ensures no damage to these kind of devices.
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