Technology Explained

How Power Outages Can Damage Your Computer (And How to Protect It)

Simon Batt Updated 05-05-2020

Your PC relies on a consistent stream of power to stay on—but sometimes, your mains supply may not be so reliable. If you live in a neighborhood prone to outages, you might be wondering: can a power outage damage a PC, and what can you do to protect yourself from its effects?


Let’s explore the risks of a power outage and how to avoid them.

The Different Types of Electrical Anomalies

The electricity flowing through your home is not constant. Electrical currents can ebb and flow, dipping above and below what’s ideal. Both too much and too little power can cause problems.

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).

There’s a similar issue called a brownout 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. These can be intentional as a way to reduce electrical loads and prevent blackouts, though they can also be unintentional.


On the other side of the spectrum, there’s the power surge. This is when an appliance receives more electricity than intended for at least three nanoseconds.

Surges happen due to several 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 lightning.

Can a Power Cut Damage Your PC?

So, can a sudden drop in power cause problems for your PC? As it turns out, yes, both for your data and your hardware.

How a Power Cut Can Damage Your Computer

The sudden shutdown after a blackout is the primary danger to a computer’s health. 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 will interrupt this sequence and may leave processes “half-finished.” This has a chance of corrupting files and threads, which then damages the operating system.

System files are the largest concern. If the operating system is busy editing an important file when the power outage hits (such as during a system update), the sudden cut will corrupt the file. Then, when you try to reboot the computer, the operating system trips up over this corrupted file and fails to boot.

If you’re lucky enough that your system files are unscathed, you may still lose vital work. If you don’t get into a habit of constantly saving your work, a power cut could set you back to square one. Power cutting out mid-save may corrupt your work.

Furthermore, frequent power outages can reduce the 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.” This is when the head touches and scrapes the platter surfaces, effectively destroying the hard drive.

Solid-state drives How Do Solid-State Drives Work? In this article, you'll learn exactly what SSDs are, how SSDs actually work and operate, why SSDs are so useful, and the one major downside to SSDs. Read More can also suffer catastrophic damage from sudden power cuts. Issues can range anywhere from data corruption to total malfunction.

How Post-Blackout Power Surges Can Damage Your Computer

What’s worse, a power outage may not be the end of your problems. An outage is often followed-up by a surge once the electricity comes back online.

A power surge will overload and fry the electronics within your PC. While an outage doesn’t do a great deal of damage to a power supply or motherboard, the subsequent surge will. This will result in a computer that won’t turn on after a power outage occurs.


As such, if you want to stay safe from a power outage, it’s worth investing in power surge protection too. There’s nothing worse than skillfully negating a blackout, only for everything to fry due to the surge afterward!

Protecting Against Power Outages

While power outages won’t tear through a computer as a power surge will, they can still do damage. As such, if you want to take care of your data’s health, it’s a good idea to invest in some anti-outage precautions.

Using an Uninterruptable Power Supply (UPS) to Prevent Power Outage Damage

For protection against power outages, you need 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.

UPS devices can also come equipped with surge-protected outlets, making them a useful two-for-one purchase. If you live in a building or location that frequently experiences outages, surges, or both, a UPS will be a strong investment.

It’s important to note that a UPS unit only powers your electronics for a few minutes. This means it’s not a great solution if you want to continue working through an outage.

However, those few minutes give you plenty of time to shut down your computer manually to prevent damage. UPSs can sound an alarm to alert you of an outage, or even tell your PC to shut down immediately.

Using a Laptop to Work Through Outages

If you instead want to continue working through a power cut, why not use a laptop? Laptops avoid the power outage problem entirely; when the electricity cuts out, it switches to the battery.

As such, if you’re in an area that suffers from power cuts frequently, it may be worth changing to a laptop. While laptops aren’t as powerful as a full PC, they’re far more usable when the power drops out than a computer.

Of course, it feels bad to buy a laptop because your power situation isn’t ideal. Fortunately, grabbing a work laptop doesn’t have to break the bank. Be sure to check out the cheapest high-quality laptops The 7 Cheapest High-Quality Laptops for Students on a Tight Budget Finding a high-performing, affordable laptop is tough. Here are the best laptops for students that don't break the bank. Read More for an affordable way to continue working through outages.

Get a Good Surge Protector for Post-Blackout Power Surges

Whichever means you choose to protect your data from sudden shutdowns, you also should enhance it with surge protection.

While this doesn’t protect your hardware from the actual blackout, it does shield it from any power surges that happen post-blackout. As such, grabbing a surge protector covers you from every danger that can occur during a blackout, while also stopping power surges in general.

Buying a surge protector can be a little confusing, as they come with specifications that detail how good they are at their job. If terms such as “UL Rating” and “Clamping Voltage” make your head spin, consult our guide on if surge protectors are necessary Are Surge Protectors Necessary? Here's What They Really Do A surge protector is not the same thing as a power strip! Here's how they're different and why you need a reliable surge protector. Read More .

Keeping Your Computer Safe

Power outages can damage system files and data and the subsequent power spikes can destroy hardware. As such, if you live in a neighborhood with unstable power, you should take the time to protect against both and save some headaches.

If you’re interested in other ways of keeping your computer safe, make sure you’re not making these common mistakes that will damage or ruin your motherboard 3 Common Mistakes That'll Damage or Ruin Your Motherboard These mistakes are simple and seemingly insignificant but can lead to motherboard damage, which will cut your computer or laptop's life shorter than you expect. Read More .

Related topics: Computer Maintenance, Computer Safety, Computer Tips, UPS.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. BODHI
    September 12, 2018 at 6:09 pm

    see next. Through this, we also become modest and realize how small the places we live in are.

  2. oksidarma
    November 13, 2017 at 5:46 am


  3. faith
    July 11, 2017 at 7:54 pm

    somedays electric cutting computer running during. solution what's?

  4. Sanchita
    January 11, 2017 at 2:24 pm

    I don't understand what this article is saying. Why should a power outage mean that power supply to the hard drive gets cut off? I am using a laptop, and if the laptop battery is charged, surely that would keep the hard drive going when there's a power outage? I shall know if the battery is about to go out, and will shut down the laptop before that happens. In that case, what's the damage to the hard drive? The article appears to talk about only desktop computers.

    • sergei
      February 14, 2017 at 3:30 pm

      It also speaks of laptops with external hard drives attached, which people in many situations do, often on constant basis due to their line of work, etc.

    • Noah Dove
      April 28, 2019 at 11:14 am

      Unless its a power surge then every device is effected.

    • JB
      December 20, 2019 at 11:29 pm

      Figured that out all on your own, congradulations...

  5. beverley Fielden
    August 1, 2016 at 6:27 pm

    I'm suffering from a real enigma of a problem
    I'm in the uk and we don't have many surges or electrical storms
    However over the past three years I have had over 30 components fail on computers and in not exaggerating
    This is not just one machine
    It has happened on various computers I have bought
    Brand new desktops two of these
    Second hand spare laptops two of these
    And my most recent purchase a £1000 laptop
    It appears the the most failed components on the desk tops is the graphic card followed by the motherboards
    The laptop fail on the motherboards
    I have had other small devices stop working too like modems and powerline adaptors

    I am using a surge protectors
    I have all the earthing in my house checked and it is all fine and connected to an RCD

    I'm at my wits end on where or what to try next

    • seth
      August 11, 2016 at 4:47 am

      Hi beverley,

      This answer is no fun, but I moved into an old home a while back and had a similar issue of frequent unexplained computer failure. The answer ended up being that the entire house needed to be rewired. Your grounding may be good, but the wires could be old(or just bad for some reason). Maybe get that checked and good luck.

  6. Clinton
    April 26, 2015 at 7:27 am


    Please could someone help me to understand the effect of a brown-out on hardware, as this was not clearly addressed in the otherwise very useful and informative article. I have an iMac 27" (Late, 2013).

    I would like to use a solar powered battery device with a 150 Watt External modified sine wave inverter. According to the Mac website, my model will use approx. 78W when idle, and 180W at CPU Max.

    So, because I live in South Africa, where we now have load-shedding (planned black-outs depending on national energy grid pressure) I have invested in an EcoBoxx 160 DC + [Broken URL Removed].

    My question is thus: If I use my Mac with the device, and it happens to demand more than the 150W generated by the EcoBoxx, would this cause damage to any of its component parts?

    I will only be using MS Word on my Mac under these conditions, so I imagine that if I close all other applications then the power demand of the Mac should not approach CPU max?

    Also, if I ran it through a surge protector, would this make a difference?

    I would be extremely grateful for any advice or suggestions, as I am desperately trying to complete my PhD dissertation, and cannot afford to continuously suffer the effects of load-shedding!

    Thanks and Warmest Greetings,

    • Afitz
      April 28, 2015 at 4:05 am

      No damadge should occur, your computer will start to have artifactingnproblems, where white boxes appear randomly on screen, and your computer may crash because its not pulling enough power.

  7. Kamakshi
    April 14, 2015 at 7:55 pm

    Yes,I think this true

  8. ED
    September 23, 2014 at 8:06 pm

    Maybe I missed it or someone already posted a comment. You also have to unplug (or at least protect) your network connections such as a cable modem or DSL because electrical anomalies
    are just as likely to come in from them as the power during a lightning storm.
    Electrical anomalies can crash your system but they can also cause latent failures that may only show up months later or as intermittent failures which may not be associated with the spike or surge.

    • Joel L
      September 25, 2014 at 12:28 am

      Yes, absolutely. Most people who unplug their computers forget to unplug their modems/routers/ethernet cables. It's a terrible feeling when you think you've taken the proper precautions only to return to a lightning-zapped computer.

  9. Adrian
    September 15, 2014 at 12:18 am

    Honestly, I've never lost data due to a power outage...that doesn't mean that it'll never happen though.

    I have lost 2 tvs, a computer, a router and a modem to a freak electical storm though. Sad thing I wasn't home when it hit. I think it's good practice to unplug your expensive equipment when you're going to be away for a while.

    • Joel L
      September 16, 2014 at 5:27 pm

      Did all of those losses occur during the same storm? If so, that's crazy!

    • Kamakshi
      April 14, 2015 at 7:57 pm

      That's cool

  10. Jim Horn
    September 13, 2014 at 12:21 am

    Laptops take the external power and send some to the battery to recharge it and the rest to the computer circuitry. If the external power fails, the battery takes over. But "all the electricity is" NOT "being channeled through the battery" so anything that overstresses the input circuits will cause laptop failure. And repairs are almost always more expensive than replacement of the whole laptop (sigh).

    (from an electrical engineer who has the schematics for his and has rebuilt the internal supplies more than once)

    • Kamakshi
      April 14, 2015 at 7:56 pm


  11. Tajwar H
    September 12, 2014 at 7:30 pm

    I've moved away from Desktops permanently in the last few years. Since Laptops run on batteries anyway, should one be worried about Power Outages/Voltage Spikes (since all the electricity is being channelled through the battery to the circuitry)?

    • Kamakshi
      April 14, 2015 at 7:56 pm

      So what

  12. A41202813GMAIL
    September 12, 2014 at 4:34 pm

    For Turning Off, I Just 'Pull The Power Cord' 99% Of The Time.

    Sometimes The PC Refuses To Boot, So I Have To Load The BIOS Default Settings And Reset The Boot Order For All My Devices.

    Sometimes, Disks Need To Do Some Auto CHKDSK Before Normal Proceedings.

    No Big Deal - So Far.


    • Joel L
      September 16, 2014 at 5:26 pm

      You really shouldn't "pull the power cord" as it doesn't give your computer enough time to properly shut down system services, which is why you often run into boot issues. It could harm your disks as well. Always use the operating system's Shutdown procedure.

    • A41202813GMAIL
      September 16, 2014 at 11:08 pm

      Thank You For Responding.


    • Fart
      February 3, 2015 at 3:19 pm

      Worst advice every, do not follow this persons advice.

      Source: I am a software engineer, and have been dealing with computers for decades.

  13. dragonmouth
    September 11, 2014 at 10:34 pm

    All great advice ASSUMING one is by one's computer 24/7/365. Most of our power outages/power surges occur when when the weather is calm, very few during storms. a few occur during the night. I have two choices, either plug all my hardware into a generator or unplug everything when not in use. Neither choice is very useful.

  14. KT
    September 11, 2014 at 10:09 pm

    I actually had a software issue from a blackout. It was Windows XP about 8 years ago. I was on a "less than family friendly" website when the power went out. When it came back on, my pc had over 4,000 detected threats on it and the fake "fix your pc" windows took over! That's when I changed to Linux btw, I needed a more secure and free way to keep visiting those "less than family friendly" websites! GFCI receptacles are a good choice too for protecting your hardware.

  15. Amrit K
    September 11, 2014 at 6:21 pm

    If power fluctuation happens more often then it may fry your hardware... nice and crispy.
    Also it may cause fire hazards.