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Is it safe to leave on your computer when it is lightning?

asked Jun 24 '10 at 20:18

DeltonOnline's gravatar image


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I used to work as an engineer at a local radio station. If you think a power strip, a surge suppressor, UPS, good grounding, or buried lines are going to protect you from a lightning strike power surge you are sourly mistaken.

We had power protection units costing many many thousands of dollars as well as massive buried ground wires in a radial pattern; and a hit to the tower, or even just a nearby hit a half-mile away would blow through them like they were nothing.

The only way to protect your computer is to unplug it from the wall, make sure the cord isn't near the outlet, unplug your router too, etc - unplug any outside connection (whether your lines are buried or not). Even a lightning strike a few miles away can damage your equipment.

The old rule of thumb - if you can hear thunder then your electronics aren't safe.

I've had so many people tell me that they never unplug their stuff during a lightning storm and never had any problems (and eventually a certain number of those people come to be with burnt-out motherboards, etc).

While statistically you probably aren't going to get a near-hit that will damage your computer - it's enough of a possibility to be concerned about.

answered Jun 25 '10 at 08:37

Lectrichead's gravatar image


edited Jun 25 '10 at 08:38

I usually wait until its within a 3 Km radius before i shut down and unplug my gear.

answered Jun 24 '10 at 23:47

DJ%20Tiger's gravatar image

DJ Tiger

I lived and worked in Florida for 10 years. Shutting down and pulling cords, ... all cords, is the only way to be fully safe. I'm now in Missouri and I still pull everything, especially the phone cord (high speed or dial-up) and/or the microwave links for extended WiFi - anything with cords leading to a "touch-point". As for running on batteries; remember that lighting is "white noise" Radio Frequencies, and - as such - it can affect your data transmission. I once ran Osborn computers on huge marine-cell batteries, but one strike which started inland around La Belle and made ground contact somewhere around Ft. Meyers Beach left me with a screen filled with weird characters top to bottom. Fortunately, I was doing a "read" from a floppy disk, but had it been writing, I would have lost my data and my FAT, so it's not just ground strikes that threaten your system(s); it's everything. A few minutes to a few hours of waiting safely is far better than lost data in a millisecond.

answered Jun 25 '10 at 11:50

Ted%20Bruner's gravatar image

Ted Bruner

This is a great question. For the most part, you're probably OK. The risk of course would be a power surge caused by lightening which would damage components of your computer. A good surge power strip can minimize this, and if it's really storming horrible outside, it might be a safe idea to power off while the worst passes. I used to think this was totally bogus, until just three days ago my mom's computer's motherboard shorted and failed due to horrible storms and a power loss. No joke. Now out of full honesty she was ready for a new computer anyway, but regardless I proved something to myself; it's real, storms can damage your computer. Use good judgement and make sure you're surge protected.

answered Jun 24 '10 at 20:26

Peter%20Murphy's gravatar image

Peter Murphy

If your house has a good ground source and protected from sudden intake of electricity, it should be fine with a power strip or better a UPS with grounding. BUT it is best just to turn off your computer at best.

answered Jun 24 '10 at 20:27

kevin's gravatar image

kevin ♦♦

edited Jun 24 '10 at 20:43

No, Let's say your power goes out. That power outage COULD cause your Power Supply to break.

answered Jun 24 '10 at 20:40

WindowsMojave's gravatar image


There is no guarantee that just turning it off will help. At least have a surge protector on it at minimum. Lightning can also get it if the plug from your computer is close to the outlet. Best solution I see is unplug.

answered Jun 24 '10 at 20:47

rocky05's gravatar image


If you have a laptop and you're worried about lightning, you can unplug the power cord. If you're on a desktop, you can turn off your computer and unplug the power cord. If you're on a UPS, you can unplug the UPS and still get at least 20 minutes of computer usage.

If there is no lightning in the area, I don't get worried about my computer. If there is lightning, I get a little bit worried, but I usually don't worry too much about it, but it only takes once for lightning to hit your computer, than it's too late.

answered Jun 24 '10 at 21:00

catchatyou's gravatar image


I usually unplug mine. Simply because I have had MULTIPLE computers burned out by lightning.

answered Jun 24 '10 at 21:16

kyle_on_the_radio's gravatar image


Power surges are what you should be afraid of, they will actually damage equipment because of voltage spike. They are hardly noticed and last only a second. Power surges are usually followed by brownouts which are drops in power (not to be confused with blackouts). Both cause damage to the computer system.

Turning your computer off won't protect it. You would have to completely unplug it or use a power strip.

I leave mine on because my entire house is well grounded.

answered Jun 24 '10 at 21:33

blackbird307's gravatar image


edited Jun 24 '10 at 21:47

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Asked: Jun 24 '10 at 20:18

Seen: 7,350 times

Last updated: Jul 22 '11 at 17:48