Isn't the lightning causing both high voltage AND high ampers? I am complete ignorant in physics, sorry.

my dad always said that as well, and always shut down computers and TVs during particularly bad thunderstorms, but nothing ever happened, even when we kept electric appliances running.

my PSUs are surge-protected. the building is equipped with a roof-mounted lightning arrester, and we don't have overhead power lines, it's all underground here. and i've never heard of anyone in the vicinity loosing electric appliances in this way.

From personal experience I can say that my PC has survived a lightening strike while powered on. The ADSL modem I had at the time, though, was not so lucky.

Said lightening strike also managed to set off one of those novelty birthday cards that play a tune when opened. No idea how it managed that one!

Long time ago, I almost had my desktop PC fried by a "lightning", but the surge came from the telephone line, not the electric network. So, it actually fried my modem, but my PC also tilted at the same time. Luckily, the PC itself ran fine many years after the incident. Where I lived, it was quite normal that the fixed line telephones would "ring" during lightning storms, meaning there were surges on the telephone line.

My understanding is that this is usually a problem only if the telephone lines go on poles, not underground. This was the case in my incident too. If you live in a city where all the lines go underground, I think you should be safe.

One clarification from my memory: the surge doesn't really (usually?) come from an lightning actually hitting the line, but when a storm cloud is "fully loaded", it's electric pulling power packs electrons and shit to the pole phone line hanging below it in the air. So when a lightning strikes from that storm cloud elsewhere and the electric pulling power of the cloud is gone, the surge from the phone line is released. Just from my memory, maybe someone has first-hand experience on it.

There are quite a lot of beliefs related to this. For example, for some reason in SE Asia it seems to be quite usual to believe that when a lightning storm comes, you should switch off your mobile phone, even if you are indoors. The legend claims that a lightning can hit the mobile phone if it is on (especially if it is active). For some reason I haven't heard such warnings elsewhere (not even on official "how to protect yourself in a lightning storm" pages), so I'm sceptical about them.

As for TVs... if you have an actual antenna on the roof of your house, yes it is a good idea to unplug the antenna cord I think.

No, you're correct about that, I double checked it and yes, you've got both high voltage and high amperage going on there.

Fun fact, as a general rule if you can see an electric spark you're looking at thousands of volts, so if you're in the dark and you shock somebody with static electricity you've got a ton of voltage, but basically no current.

First comes the very high voltage which fry the equipment because his isolation is not rated for such a voltage. After the isolation is destroyed a high current will appear and the circuit breaker (or fuse) will trip but as you can see that would be too late anyway as the equipment is destroyed. The circuit breaker does a good job anyway because in some cases it will prevent a fire from starting.

The reason for the ringing is most likely related to insufficient shielding and or an improper ground. Whenever you have charged particles moving they will generate a magnetic field and a moving magnetic field will then induce current in cabling. If you have a sufficiently strong field it could do that. Keep in mind that phones are low voltage equipment. If they're in the ground then it shouldn't be a problem as that's where the charges are trying to get to. There may be cases where the charge does go up, but for that to even be plausible you'd have to be right at the site of the strike for that to be at all plausible. This is rather complicated, the problem with the idea that lighting is causing this is that it's rather unlikely to be the case. Electricity flows through the path of least resistance to ground and will generally take the power cables which are higher capacity over low voltage gear. The low voltage gear also generally sits lower on the pole for reasons do to worker safety. Any voltage that does travel down the line would be meeting substantially higher resistance from the tiny phone line and when it hits the ground at the house, would then be directed downward to the ground.

Induced current is a much more reasonable explanation, and would be caused by the static in the air during the thunderstorm rather than by the lightning itself. Although whenever you get that sort of pulse of electricity there is an accompanying EMP blast that can also damage equipment or induce those sorts of currents.

I live in a flat where we have/had lightning arresters too, but now the copperprices are so high there were thieves that nicked it from the building. It's crazy, they even steal the powerlines from the trains and bronze statues from squares.

you build a new motherboard?

thats helluva impressive. I just can't imagine the amount of work and number of people you had to hire just to do that. Also arranging an access to hundreds of factories, processing plants and assembly lines...

wow. I am speechless.

Exactly.

It is, but circuit protection has a another, lesser-known rating: arc-over. This is the voltage at which you will experience an arc even though the protection device (fuse, circuit breaker, or overload) has tripped. If you've ever seen a little spark when flipping a switch, this is kinda what arc over is. Take a look at a typical small fuse (not sure if household screw-in fuses display this rating) and you'll see something like "5A 250V". That means it's made to trip at 5 Amps and is tested to not arc unless the incoming voltage exceeds 250V. Now, it's probably going to protect from arc at much higher than that, but 250V is a pretty standard tested rating over here.

If we think about it this way, lightning itself is just a giant arc-over event so crossing that gap from an open fuse or breaker is pretty small potatoes for a lightning bolt that traveled a mile or more through open air.

Thanks for clarification. I plug out my laptop during the storms anyway, but it's good to know that common fuses (not screw in, but with switches, actually) can't protect me from the storm if I'm unlucky.