Quick question:
Can lightning damage a laptop adapter or cellphone charger inside an apartment even if no devices were attached and drawing power from the adapter/cables/charger at the time?
Yes.
Sure, lightning could damage most anything; but it would practically have to hit your house to fry your electronics if they’re unplugged. Whereas, if they’re plugged in, it would only have to hit the power line.
Lightning already jumped through a few miles of open air. At those insanely high voltages, things that you don’t normally think of as a conductive path (like air) become conductive.
Lightning does have a tendency to follow wires and plumbing, but it can easily jump from a wire inside the wall to a power cord or an unplugged electronic device. It will usually only do that kind of jumping on a direct strike.
If the lightning hits further away, it is much less likely to jump over huge air gaps, since the voltage will decrease. Decreasing voltage is relative, though. Lightning strikes at a few million volts. If a spike of “only” a few thousand volts comes down the line, that is still more than high enough to completely fry anything plugged into an outlet, regardless of whether the device was turned on or not. For these types of indirect strikes, having things unplugged when not in use is usually adequate to protect them.
It is possible to almost completely protect a building from even a direct lightning strike, but it is ungodly expensive and I’ve never heard of it being done for anyone’s home. If you are curious, google things like Ufer grounds, Faraday cages, and Halo/Ring grounds. We’re talking hundreds of thousands of dollars or more to install some of this stuff.
For your home, nothing you can buy (economically) will protect you from a direct lightning strike. There’s just way too much energy in a typical lightning bolt. You can protect a lot of things with a surge protector. Note that not all power strips have surge protectors in them, and the el-cheapo power strips that advertise having surge protectors may have fairly wimpy protection. What these power strip type surge protectors actually do is they have a thing called a metal oxide varistor (MOV) between each wire. When the voltage gets too high, the MOV effectively “turns on” and provides a direct short circuit, which snubs the incoming power spike. This also usually fries the MOV as it does so. El-cheapo power strips won’t have any indication on them if the MOVs are blown. Cheapie power strips also might only have one MOV in them. What you really want are MOVs on all of the wires, between each wire, so that they’ll snub any kind of spike. A good surge protector will have an indicator light telling you that the MOVs are still functional.
The clamping voltage is the voltage at which the MOVs turn on. If the surge protector has a higher clamping voltage, then it will let a higher and more powerful spike through before clamping it, which is a bad thing. So the lower the clamping voltage, the better.
The higher the joule rating, the better. A cheapie surge protector may protect you from a couple hundred joules. A better one may be closer to a thousand. To put it in perspective though, a typical lightning bolt has about a billion joules of energy in it, which is why nothing you can buy from ye ol local Home Depot can protect you from that. A lightning strike half a mile away might travel down the power lines and hit your house with a few hundred joules of energy still in it though, and that is what these surge protectors will stop.
You can also get whole house surge protectors, which is basically like what is in the power strip, except it installs at your electrical box and has a much higher joule rating. Some of the cheaper ones aren’t much better than a cheapie power strip though, so shop carefully if you are considering one of these. Whole house surge protectors often require an electrician to install them.
How much current the surge protector can handle also matters. Typically they’ll shunt up to something like a few tens of thousands of amps, but only for a short time. The higher the number, the better. And again, a typical lightning bolt has a few hundred thousand amps behind it, so nothing you can practically buy will protect you from a direct strike.
Power surges from lightning can also go thru phone lines.
I did an IT support call to a small office that lost multiple modems and a fax machine.
Back to the OP, I think what Velocity may not realize–and this seems to be the crux of the question–is that if a charger is plugged in, even if no device is plugged into it, the power supply itself is completing a circuit and drawing current. It doesn’t draw much, but there is a complete circuit, and if there is a big voltage surge on the line it can fry the charger.
Absolutely.
Electricity can also jump gaps, roughly 1 cm for every 20,000 to 30,000 volts or so (varies depending on humidity, shape of the electrical conductors, and other factors). This means that if you have a power strip and you turn it off, a large enough voltage, like a few thousand volts from a spike, can easily jump across the switch contacts.
So even if the device can be turned off with a hard mechanical switch, it still could be damaged. It doesn’t necessarily even have to be a charger or a laptop power supply type of device, although those are more easily damaged.
Yes it certainly can. Such a device is plugged into the wall outlet, but the current flow is interrupted by a switch, which has a gap of maybe 1/4th inch between the switch contacts. That’s nothing to a lightning bolt, that has already jumped a gap of several miles between the clouds an the ground.
Years ago, a friends’ house was struck by a lightning bolt that hit the electrical mast where the power wires entered the house. Afterwards, you could walk through the house and see the path of all the wiring in the house – on the plaster walls, there were scorch marks going from the switches up the walls and across to the ceiling lights, scorch marks from one outlet to the next, etc. They were very lucky that the house didn’t burn down. (Incredibly, much of the electrical wiring still worked after that. But they had to move out for weeks, while the house was entirely rewired & then walls repaired.)
And thats why lightning can damage things are not even switched on or even plugged in.
If that thing presents a path to ground, better than the other, it may get the lightning’s power through it. The thing is that the buildings designated ground connect may already have been destroyed, and the lightning seeks out 2nd, 3rd, 4th etc paths, and even in parallel as conductors increase in resistance with temperature AND amperage… So thats why it would decide to travel through an otherwise insignificant cable… just because it was a path to ground , not neccessarily the best or even good path to ground.
If something is plugged in to the socket, it really doesn’t matter whether it’s turned on or off: it’s still at risk for being fried if lighting hits somewhere on the power line. Surge protectors might help, if it’s a very mild pulse, but nothing will help a if there’s a nearby direct strike.
If something electrical/electronic is not plugged into an outlet (laptop sitting on a wooden table, not plugged in to any socket), then it’s at no more risk than anything else in your house (and it doesn’t matter whether it’s off or running on battery power). Sure a direct strike on the house could destroy the laptop, but only by destroying the table and floor, too (either directly or by starting a fire that burns it all), and that direct strike is pretty rare, compared to a surge along the power lines.
Bottom line: unplugging electronics in a thunderstorm could help, but turning them off won’t make any difference.
as engineer_comp_geek said, lightning just jumped through a few miles of air. if you experience a direct strike, you should be more concerned about your house burning down instead of whether your laptop survived.
Jerry Pournelle many years ago described an incident where someone a few blocks away hit a high-voltage power pole and dropped the 15,000 volt lines onto the local house power lines. He said everything in the house (and the neighbourhood) exploded - appliances, light bulbs, computers and monitors - except some devices plugged into a particular set of surge protectors.
Think about the make-up of a typical switch. There’s a rocker (usually) or a push-button, which moves a piece of metal a fraction of an inch to make contact. Lightning, as others point out, has already jumped through a mile or more of air; that fraction of an inch won’t stop it. Plus, so many devices now are “instant-on”. Your TV when off, still has live circuits drawing minimal power and looking for the remote’s infrared signal. Modern computers provide power so the network card can provide “wake on LAN” even if 99.9% of computers never use it. (Just look - odds are the indicator lights on your PC’s network port are blinking away even though the power is off) Those circuits are live, providing lightning a much easier path to blow up the innards.
(I have seen a PC which sustain some serious burn marks from a lightning strike near the building. The power supply was toast, but techs swapped in a power supply from a compatible PC and it booted up. It depends on exactly how much power made it to the device. The Network switch was not so lucky, several network ports had burn marks around them and it was dead, dead, dead…)
And that’s the surge protector I want.
I remember that issue of “Computing at Chaos Manor.” I was a Byte subscriber at the time, long ago and far away.
Anyway, I found that column (August 1989) online. Ye cats, that was 30 years ago!
Pournelle identifies it as a “Compuguard” brand. After 30 years, I make no guarantee that anything you google up by that brand name would have anything to do with the original surge protectors in that column.