The Effects Power Outages Can Have On Your Computer

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Do you unplug your computer during severe storms? If not, you may want to start.

It’s long been known that frequent electrical storms and power outages can damage electronic devices or full-out destroy them, and that includes computers. Anyone who claims otherwise is lying or misguided. The worst part is that power outages aren’t the only concern.

What are the risks of electrical failure? How do they impact your computer? And what can you do to protect your computer from being fried?

The Different Types of Electrical Anomalies

The electricity flowing through your home is not constant. Ideally it would be, but the reality is that electrical currents can ebb and flow, sometimes dropping in voltage and other times surging with extra power. All of these can have undesirable effects.

When power completely shuts off, it’s known as a blackout. These tend to occur due to issues beyond your control (e.g., power station disruptions, damaged electrical lines, etc.) but sometimes they can be self-inflicted (e.g., by shorting or overloading circuits).


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And then there’s a similar issue called brownout, which is when your electrical voltage experiences a temporary drop without fully blacking out. If you’ve ever seen your lights dim for unknown reasons, it was probably due to a brownout. Brownouts can be intentional as a way to reduce electrical loads and prevent blackouts, though they can be unintentional as well.

On the other side of the spectrum, we’ve got the power surge, which is when an appliance receives more electricity than intended for at least three nanoseconds. Surges can be caused by a number of factors, including short circuits and electrical line malfunctions. If the increased voltage only lasts one or two nanoseconds, it’s a power spike, which is most commonly caused by lighting.

Why Blackouts and Surges Are Dangerous

The real danger of blackouts and brownouts is the unexpected computer shutdown. Operating systems are complex and they must go through a “shutdown sequence” to make sure all running processes have correctly terminated before powering off. A sudden loss of electricity can interrupt important threads and leave your computer in an inoperable state.

System files are the largest concern. Consider what happens when a hard drive is writing data to the disk but suddenly shuts down in the middle of it. Suppose the file being written was a system file necessary for the booting process? Now that file is corrupted and you can’t boot up your computer without going through an involved recovery procedure.

Furthermore, frequent power outages can reduce a hard drive’s physical lifespan. The read-and-write head, which hovers over the spinning platters during operation, snaps back into its original position upon power loss. This sudden movement can cause tiny imperfections that accumulate over time, increasing the likelihood of a “head crash”: a malfunction that occurs when the head touches and scrapes the platter surfaces, effectively destroying the hard drive.

Solid-state drives can also suffer catastrophic damage from sudden power cuts. Issues can range anywhere from data corruption to total malfunction.

It should be noted that although power outages will not cause direct harm to computer hardware other than data drives, it’s possible for power outages to be accompanied by power surges, which can cause severe damage to hardware.


As far as power surges and spikes are concerned, your biggest worry should be lightning. Most homes are built with electricity lines that deliver somewhere around 120 volts. The current of a lightning strike, however, can exceed several million volts. That’s like trying to fit the flow of Niagara Falls through a straw.

Electronic devices aren’t designed to withstand that kind of influx and if the power of a lightning strike ever surges through your lines, you can be sure that any unprotected device will be fried beyond repair.

The next time you decide to use your computer during a storm, don’t be surprised if a spike hits and you have to say goodbye. It’s more common than you think.

Protecting Against Power Outages

The only foolproof way to protect your computer against electrical anomalies is to unplug it completely until the danger has passed. Seriously, it has to be physically disconnected. Flipping your power switch to “off” isn’t going to cut it. This is the only method of protection with a 100 percent success rate against power outages and power surges.

That being said, some of us are probably going to ignore the storm and stay plugged in regardless. It wouldn’t be the smartest move, but definitely understandable. In that case, there are two semi-effective alternative methods.


Against power surges, you’ll want a surge protector. This apparatus, which looks like a bulkier version of a power strip (the two are not the same), will attempt to divert electrical surges away from the devices plugged into it. Surge protectors are rated to withstand a certain maximum voltage and once they’re triggered, they must be replaced.

If you need help picking one, we have a guide to buying surge protectors. Note: No surge protector will protect you against lightning strikes!


Against power outages, you’ll want an uninterruptible power supply. This apparatus contains a backup battery that will continue to provide power to your computer even when your power goes out. Most UPS devices only last a few minutes, but that should be enough time for you to issue a proper shutdown.

UPS devices can also come equipped with surge-protected outlets, making them more of a two-for-one purchase and offering more value per dollar. If you live in a building or location that frequently experiences outages, surges, or both, a UPS will be a strong investment. If you need help picking one, we have a guide to buying uninterruptible power supplies.

Sudden changes in electrical voltage can cause real damage to your system and/or your hardware. Don’t fall into the trap of thinking it would never happen to you. Protect yourself early, protect yourself adequately, and don’t forget to backup your data!

Image Credit: Flashlight Via Shutterstock, Lightning Strike Via Shutterstock, Surge Protector Via Shutterstock

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