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Heard popping sound and saw a flash after a thunder strike near my equipment
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FlevasGR:
Hello all,

Today i had the worst experience of my life (yet). The power went down and as always i flipped the switch which is located on the outlet (Australian outlets) to avoid high voltage once it comes back. I didn't think to pull the cord because it was just a simple power outage. That was the main outlet by which my computer, my server and my networking equipment draws power from.

Within few minutes thunder strikes started popping right and left and i totally forgot that i was still connected to the wall. I know that i may be over-reacting but even with a single thunder strike i always shut down everything.

At some point i saw a blue flash and heard a popping sound near the shelve where my networking gear is and right after i heard the sound of the thunder strike. My heart dropped to the floor. I knew that something bad had happened to my stuff and i could not wait for the power to come back to test and assess the damage.

After half an hour the power comes back and after waiting for 15 minutes to make sure that everything was okay i plugged everything back and flipped the switch. Ty my surprise, nothing was damaged. Both switches, my server, my pc and my access point were functioning as intended. I still cant wrap my head around what happened. I don't really have good protection yet. Only a single, decade old, Belking surge protected power strip.

I feel very uncomfortable not knowing what happened.

Do you have any ideas what caused the sound and the flash?

Note: All windows and blinds where closed. It didn't came from the outside.
engrguy42:
The thunder sound you heard was extremely high voltage lightning. It can hit the utility wires and set up a very fast (microseconds) extremely high voltage wave travelling and bouncing all over the power system from the point where it strikes.

The utility has "lightning arrestors" placed at various points on the power lines. These are typically MOV's (metal oxide varistors) that are basically nonlinear resistors that will act as a very low resistance to super high voltages, thereby shunting those high voltages to ground. Older ones are just like arc gaps that shunt the wave to ground.

However, sometimes there's no MOV around, and these travelling waves of high voltage can bounce around the power system, and when they hit a high impedance they can even double in magnitude.

It's possible one of those waves got past the transformer feeding your house and into your 230V wires and into your house. We're talking maybe thousands of volts in a wave that lasts maybe 10 microseconds or something. ZAP!! Your wall outlets and switches might not be rated for something that high.

BTW, don't count on those surge arrestors in the outlet strips. Often they tend to respond so slowly that the damage is done before they wake up.
FlevasGR:

--- Quote from: engrguy42 on May 21, 2020, 08:33:40 pm ---The thunder sound you heard was extremely high voltage lightning. It can hit the utility wires and set up a very fast (microseconds) extremely high voltage wave travelling and bouncing all over the power system from the point where it strikes.

The utility has "lightning arrestors" placed at various points on the power lines. These are typically MOV's (metal oxide varistors) that are basically nonlinear resistors that will act as a very low resistance to super high voltages, thereby shunting those high voltages to ground. Older ones are just like arc gaps that shunt the wave to ground.

However, sometimes there's no MOV around, and these travelling waves of high voltage can bounce around the power system, and when they hit a high impedance they can even double in magnitude.

It's possible one of those waves got past the transformer feeding your house and into your 230V wires and into your house. We're talking maybe thousands of volts in a wave that lasts maybe 10 microseconds or something. ZAP!! Your wall outlets and switches might not be rated for something that high.

BTW, don't count on those surge arrestors in the outlet strips. Often they tend to respond so slowly that the damage is done before they wake up.

--- End quote ---

Well, isn't it weird the no damage was made? I don't trust these strips either and the switch on the outlet will definitely not prevent high voltages from arcing over.
engrguy42:
Keep in mind a lot of electronics devices in your house have their own MOV's internally for stuff like this as well as other overvoltage protection. And the high voltage can flash over to ground at any point in your house wiring, so it might not even get to the important stuff.

But whenever I hear the boom-booms start I go unplug all my computers and electronics and stuff.  :D
Syntax Error:
My theory, a nearby lightning strike may have electrified your building, and even the air inside your room. So the blue flash was real! Your kit would have escaped because it's casing was at an equal potential to the electrified air. The popping sound could have been the charge finding it's way to earth - a bit like the way static used crackle away when a cathode ray television was turned off. Isn't nature shocking?

P.S. you might be able to your storm event here: http://en.blitzortung.org/historical_maps.php?map=22
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