How to Protect a PC in a Thunderstorm

Four Parts:Removing power sourcesUsing surge protectorsPreventing data loss during outagesAssessing storm damage to computing equipment

The Earth has 100 lightning strikes per second - about 3.6 trillion per year. Lightning damage to home electronics happens when a strike brings an excess of energy to utility poles. This energy then surges through our power and telephone lines right to our outlets. It's an unfortunate fact that someone, somewhere is going to have their computer fried by lightning. Read on to find out how you can prevent such damage.

Part 1
Removing power sources

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    Unplug all cords connecting your computer to the wall before the thunderstorm begins. Both power cords and modem cords need to be removed.
    • Unplugging before the thunderstorm is ideal, but it may be the case that you are not near your computer when the storm is threatening. Fear not, there are other preventative measures.

Part 2
Using surge protectors

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    Use a surge protector. This is not to be confused with a power strip. A surge protector will look like a bulky power strip. When your home receives a power spike, the surge protector takes this spike and pushes it away from the outlets and your computer.
    • For ultimate protection, if you happen to be home, unplug the surge protector in the case of a threatening storm.
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    Make sure you're buying a good surge protector. Look for the following features:
    • The surge protector should cover lightning strikes. Some do not.
    • If you regularly connect your computer to a modem, ensure the surge protector has a modem outlet.
    • Look for a surge protector that offers insurance to cover the loss of properly attached equipment.

Part 3
Preventing data loss during outages

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    Determine if your electronic set up requires an uninterruptible power supply device, also know as a UPS device. Whereas surge protectors protect surges of power, these UPS devices protect against outages. Outages and dips in power, even if minor, can cause hard or soft damage (like data loss) to certain equipment - for example, external hard drives or advanced telecommunication equipment.
    • A UPS will be particularly beneficial if you have a home office or continually run operations on your electronics.
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    During thundery seasons, do long term data backups on a more opportunistic basis. Do it well before days with a threat of lightning make it a risky thing to be doing.
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    Unplug important equipment if going away for a day or two in thundery seasons.

Part 4
Assessing storm damage to computing equipment

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    Consider if damage has already occurred. Even if your computer appears to be working you should still give it a check over in case a strike has left it in a dangerous state that might result in electric shock or fire.
    • If any of your telephones or other electronics show signs of damage, it's wise to assume that your computer took a hit too.
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    Unplug the computer and check the outside of the case for signs of smoke or burn marks (especially around the power supply at the back).
    • Use your sense of smell. If your computer smells acrid, there may be invisible damage.
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    If you suspect damage, bring your computer to a local repair shop to get a professional opinion. You may be able to recover your data.


  • Consider habitually unplugging your valuable electronics before you leave the house, even if you use surge protectors.
  • During a thunderstorm, use an old laptop connected thru WiFi if you really need to use it for emergency information. That way, if something goes wrong with it, it's not such a big loss.
  • Put a couple of meteorological lightning tracker sites on your mobile to watch what's over the horizon.


  • Never touch cords or wires, or the things connected to them, during a thunderstorm—even to unplug your equipment. People have been electrocuted while unplugging their electronics during thunderstorms. Better your computer than you!

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Categories: Hardware | Maintenance and Repair