Storm and lights dimming - pc still on

[lpiotrowski211]

Hello. I have an question. There was a storm in my country yesterday. Power was on . But there was random 1 second lights dimming in my house. Pc was still on, and laptop was still on. So why both computers was on and wont turns off when lights was dimming? Thanks. And is this harmful to pc?
How can i check that nothing damage in my pc?
Ah i dont have UPS.

Psu is Corsair 750RM and MB: Asus Z170-P

[xeromist]

In the US we call this type of issue a brownout. Rather than the power going out completely the voltage dips. This is very dangerous for electronics and appliances as incorrect input voltage can stress or damage components. It's most dangerous for motors like refrigerators. Officially all ATX components should be able to mitigate this but compliance and robustness varies. It's best to have some sort of UPS that will kick into battery mode when the voltage dips. A UPS will also protect you if the voltage spikes as the brownout ends. At the very least you should use a surge protector in case the voltage spikes.

If you don't have any form of power conditioning the best thing to do is power down and/or unplug electronics and appliances until the lights stop dimming. This will protect your stuff from voltage spikes and unprotected appliances from undervoltage (like your refrigerator compressor).

In answer to your question about checking damage: if your PSU is working then it's probably OK. Electronics can handle 10% variation in voltage by design. So as long as it never got below 90% nominal everything is fine. Also, the way power is delivered to homes it's possible your lights were undervolted but your PC was not (depending on how your house is wired). If you are concerned, there are PSU testers available for purchase. They aren't cheap but it doesn't hurt to have one around if you build a lot of your own machines.

[Korth]

Your laptop has a large battery, it always runs off this battery with or without external power. It effectively already has a battery UPS.

The desktop has a PSU has some "hold time" which can sustain power delivery and regulation during momentary electrical failures.
ATX standard requires a minimum of hold time of 16.67ms (1/60 of a second, one 60Hz AC power cycle).
Flickering lights and blinky clocks don't have PSUs which provide adequate (if any) hold time.

You really should have a battery UPS if lightning storms and sudden power transients are common. Or at least avoid using your AC-powered computers during lightning storms, lol. The risk of electrically fried hardware is low, the risk of permanent data loss/corruption is low, but they are entirely avoidable risks.

[lpiotrowski211]

My laptop have not battery. Its plugged to cord. Also according to my pc. I must now run stability tests to be sure that something wrong happened or not?

[Korth]

If it still works then you don't need to run tests to see if it still works.

[lpiotrowski211]

So it can harm pc if during storm my lights in house flickered for 1 seconds? How can i check if my pc is ok? But like i said pc not shutdown during this day with huge WIND. Only lights in house flickered few times for 1 seconds,thats all.*

Ps:
That was not storm,but only huge WIND.*

[Korth]

http://www.wikihow.com/Protect-a-PC-in-a-Thunderstorm