Just as care must be taken to prevent the infection of your computer with malware and viruses, care must also be taken to prevent power problems from harming your computer. In this article, we will discuss the various options that are available to protect your equipment from errant power quality issues.
There are a variety of power problems that can cause different issues for modern computers and electronic equipment, and there are different products available to mitigate those power problems.
In Iowa, we are all familiar with power surges. These often accompany lightning strikes and even when your power company is in the process of fixing a blackout. Small power surges can also occur when equipment like air conditioners or large refridgerators cycles on and off. A power surge is a brief burst of higher voltage sent into the equipment from the wall outlet. A large power surge can cause current to jump connectors inside the electronic device and destroy its functionality. Small surges can also have a cumulative damaging effect. Power surges are most easily and inexpensively mitigated by surge protectors. The three primary statistics to look at when shopping for a surge protector are the clamping voltage (lower is better), energy absorption/dissipation (higher is better), and response time (lower is better). A good article on surge protector ratings can be found at howstuffworks.com.
Undervoltages can also cause problems with computers and electronic equipment. An undervoltage can happen when large power draws like an air conditioner or a refridgerator compressor starts or even when the power company cannot keep up with demand. More severe undervoltages are called "brown outs" and can be very damaging to electrical equipment such as large electric motors. Surge protectors offer no protection for undervoltages, but there are devices that can mitigate those problems.
The first such device is a line conditioner. A line conditioner takes the voltage at the wall outlet and will correct it to a constant voltage in the event of either a spike or an undervoltage. Line conditioners contain no batteries and are useless for blackouts. They are rather expensive when compared to surge protectors and are comparable in price to low-end uninterruptable power supplies.
An Uninterruptable power supply (UPS) has a battery pack and does the job of a line conditioner during surges and undervoltages as well as keeping your equipment running for a short time on battery power during a blackout. The ratings to pay attention to when looking at a UPS are the number of "VA" that it can support (VA = Volt-Amps - a measurement of power that it can allow to run through the UPS) and the runtime. Many UPS units have communications ports and will compe with software that will allow the UPS to do an orderly shutdown of your computer should you lose power. Inexpensive UPS units can keep a personal computer running long enough to shut it down, but often cannot keep them up long enough to do any real work during an extended blackout.
For longer black outs - periods where you have lost power from the grid - the best power security that you can have is access to a generator. Generators do nothing to protect your electronics and electrical equipment from surges or undervoltages, but they can provide enough power to keep a freezer or furnace running and allow for the use of your electronic equipment. Small portable generators are not greatly expensive, but sizes (and costs) have no ceiling depending upon your application. When considering the purchase of a generator, you must first "size" it to determine how much power you require to run what needs to be run. A sizing guide can be found here and at the website of any other company selling generators. Keep in mind that if you are going to run electronic equipment from a generator, you will need to make sure that it produces less than 10% harmonic distortion of its generated AC wave form.
Appliances and equipment can be plugged directly into a portable generator when it is needed, or a special switch can be wired into your home that will allow you to power some or all of your home from the generator. The "transfer switch" is a switch that will disconnect your home from the grid and take power from the generator during a blackout. These are required so that your generator is prevented from back-feeding power into the grid while the power company is working on it. You can obtain a manual transfer switch for portable generators or, if you have a permanent "built in" generator, an automatic transfer switch that will trip during a blackout and start the generator without any interference from the owner.
Two last things to keep in mind about lightning in Iowa. Most modern electronics lack a physical "off" switch, so shutting them down does very little to protect them during a lightning storm. It would be better to shut the equipment off and disconnect it from the wall should you prefer to do that before an approaching storm. The other thing is that a power surge can and does travel through telephone lines as well as power lines. Most new surge protectors, and even some line conditioners and UPS devices, come with RJ11 in and out connectors to allow for the filtering of spikes from those lines as well.