Ever since I was a wee boy, my dad has always had us shut down and unplug all the computers in our house whenever a thunderstorm rolls through. He claims that a power surge from the lightning striking near a powerline could fry them. As I've gotten older, I've realized that I haven't ever heard anyone else talk about this. Is this my dad being paranoid, or is this actually a problem? I figure that most of you have probably put a good chunk of money into your computers, and would know what is/isn't a danger to them.

It's entirely possible that a lightning strike can cause a surge in the electrical net capable of knocking out electronic equipment, but such strikes are very infrequent.

I've read it can happen, but it's not just computers. Any of your electronics can be affected if a lightning strike causes a power surge. It's pretty rare though, from what I understand. I have my rigs each connected to an UPS, which also offer surge protection.

Lightning hits power lines about 1k times a second and 99.999999% of the time you're fine but if it hits those overhead cables you guys seem to love having in residential areas and your fuses/circuit breakers don't trip sure it can fry electronics if your that worried about it get a surge protector.

Not 100% sure but after moving to a location with power stability issues during storms I have had to repair a computer of ours on multiple occasions. The issues have gotten better and I haven't had any more trouble. So I'm open to the possibility of it being true.

I know (several) people who got their routers/modems fried during storms. All electronnic devices with 'cheap' power supply and/or without surge protec' shall meet the same fate.

Personally, regarding computers, I think that power supplies (from the present, not those from two decades) are meant to die before frying the MoBo.

An out of order PSU is probably one that 'jumped the grenade' on the lightning bolt, I daresay.

Yes, your dad isn't just quoting an urban legend, it's real. If your computer isn't protected it can be fried by a particularly bad lightning strike, so make sure you have a surge-guard power strip if you live in an area that has them on a regular basis.

http://en.wikipedia.org/wiki/Voltage_spike

About a year ago my computer got fried. It wasn't even plugged in - it was attached via ethernet to a router that was attached to the phone line. I went to ASUS to replace my motherboard - they told me that surges through the phone line is the single biggest cause of motherboard failure in my city.

My ADSL router got fried by storm few years ago. Also, I remember my friend telling me that almost all of her household electronics got fried, I'm not really sure if it was at the same time as my router.

So yes, it's true. You have 1:1000000 chances to happen to you. but if it does....

It doesn't even have to be lightning, it can be any voltage spike, but the ones that happen after a power outage are particularly bad. When power is restored, regardless of the cause of the outage, that power is going into ALL of the various things in your house that are plugged in and on, which can cause a huge spike as well. So unless you have a good surge protector/power strip, it's possible to fry any (or all) of your electronics even from a "standard" power outage. Direct lightning strikes provide a lot more oomph, though.

The phone company should have been the one to pay for that. They're supposed to ground the box where it enters your property specifically so this sort of thing doesn't happen. It's a good thing that nothing worse happened.

But, a more usually concern is the damage caused by dirty power to things like HDD.

Lightning fried my modem, router, and two out of three computer's network cards.

So, don't forget that it can come in through the cable either.

Normally when people think that it's the other way around, the lightning using the cable as a ground rather than entering through the house. Unless the installation was done incompetently, which could very well be, then it should be a case of the lightning strike getting in somewhere else and exiting through the cable.

Seeing as how this house got cabled many, many years ago and only recently had some issues corrected, the cable was definitely the path in.