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#25 Reply
Posted by
Neper
on 22 Aug, 2021 19:37
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I live in the very centre of a West-German city of about a million, in a flat, surrounded by a bunch of much higher buildigs.
25 years ago, we had a hit in the close vicinity which toasted my Amiga 3000 computer (worth a few thousand in those days) and some assorted radio equipment. Luckily, all of that was insured.
A few weeks ago, we had another hit very close (too near for any discernible delay between flash and bang). At the same time, there was an audible 'Zapp!' in the corner below my desk, where the Fritzbox and all the comms and network equipment live. The victims: a temp sensor in the back yard, the Raspberry Pi it was connected to and the connected WIFI router. All of that on the backyard side of the building. The 'Zapp!' here in front must have been a spark gap or just a discharge from a wire to ground. Pheeewww...
Other tenants in the building reported various fried modems, routers and other small stuff.
I'll be 67 in a few weeks and I've decided I'm not overly concerned about the next hit in another 25 years.
Ralf
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#26 Reply
Posted by
Neilm
on 23 Aug, 2021 18:10
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I'm probably overly paranoid, but I do unplug the car if there is lightning around
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#27 Reply
Posted by
james_s
on 23 Aug, 2021 18:13
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Assuming you mean an EV charging cable I wouldn't say that's paranoid at all. Given the cost of a car and the fire risk of a lithium battery I'd say unplugging it from the charger during a lightning storm is probably a wise decision.
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#28 Reply
Posted by
rfclown
on 25 Aug, 2021 01:10
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Here in Florida, I pretty much try to only have things plugged in when I'm actively using them. Lost an ethernet port on a higher end Dell Precision laptop few years ago and have been paranoid ever since. Really should get around to fixing that someday, but the wifi still works. Cloud to ground lightning strikes are very common here. I think the only thing I leave plugged in all the time is my coffee pot just because it's cheap and I will fail at life if I forget to reprogram it.
Also live in Florida, Tampa Bay area (some consider as lightning capitol), our Stanley Cup Champion Pro Hockey team is the "Lightning"!
We've also lost some electronics, and agree the safest is unplug sensitive electronics. Also known a couple folks that have been "hit" indirectly by lightning, one was killed.
Best,
I'm another Floridian. All my test equipment are on power strips, and I usually turn off the strips when I'm not using the equipment. When lightning starts and I'm not sure if the strips are off I go and make sure they are. I've got lots of older gear that I want to keep working. The questions makes me wonder how much voltage it takes to arc across the off switch of the strip. Had a friend in the 80's that had foil wallpaper in the kitchen (rented house). Lightning hit the phone line and the wallpaper in his kitchen blew out.
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Somewhat ironically, forum member joeqsmith posted this video a few years back after a nearby lightning strike took out some of his gear. As a viewer i found myself fortunate to be able to watch his knowledgeable analysis and repair of some of the damaged equipment.
https://youtu.be/40TaqXOIrHoA cousin of mine that lives in the Atlanta area had a direct strike recently that took out all of their (consumer) electronics and unfortunately did a great deal of damage to their home's wiring. They are currently dealing with insurance and looking at lot's of work to get their home liveable again.
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#30 Reply
Posted by
james_s
on 25 Aug, 2021 05:49
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I'm another Floridian. All my test equipment are on power strips, and I usually turn off the strips when I'm not using the equipment. When lightning starts and I'm not sure if the strips are off I go and make sure they are. I've got lots of older gear that I want to keep working. The questions makes me wonder how much voltage it takes to arc across the off switch of the strip. Had a friend in the 80's that had foil wallpaper in the kitchen (rented house). Lightning hit the phone line and the wallpaper in his kitchen blew out.
A direct lightning strike will probably blow though the switch in a power strip like it isn't even there. Typically the contacts are going to have maybe 3-5mm of separation so you can look up the breakdown voltage of that distance through air. If I were in an area that had frequent lightning I would unplug it completely.
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You are all just arguing about the size of the "you are toast' zone. Unplugging vs turning off. That lightning bolt jumped an air gap somewhere between a few hundred meters to a couple of kilometers getting to the ground. It dissipates over a region that is more than a few meters, and may be guided by power lines for dozens or hundreds of meters. It is impossible to quantify the odds and nearly as hard to quantify the damage costs. The only thing you can do is make yourself feel a bit better about the situation. Each individual will have a different trade between the nuisances of a bit of extra protection and the comfort of feeling safe. No one here has mentioned putting their lab in a heavy duty Faraday box with large scale interuptors on all penetrations.
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#32 Reply
Posted by
1audio
on 27 Aug, 2021 04:00
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I was involved with the design and manufacture of surge protectors for a long time. I learned a lot. First the wiring in US outlets can arc over at around 750V and the peak current will be 3KA or less inside the building if the surge comes in the power line. However it can arc over a power switch or breaker. A company in the US was offering a product that would detect lighning (AMS has a nice chip for that) and upen a solenoit switch with a 2"/50 MM opening to ensure no arc. Second a surge protector that doesn't encompass all the incoming connections will make everything worse. The power, network cable (if TV), phone line all need to be protected together. Even if the lightning doesn't hit your house or the pole outside the 100KA can induce a lot of current in any nearby wiring. Third the damage to your equipment may not be the lightning but associated voltage surges as grounds and power connection get blown open in the power distribution system.
Most recent and current electronics have internal surge protection and are pretty good if the surge comes through the power. However I have seen the internals of electronics charred between the network/coax/phone connection and the power ground enough to always advocate for a full suppressor close to the equipment. There is no downside to having lots of surge suppressors all over the house/building. Just be sure to connect the network cables through them.
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#33 Reply
Posted by
james_s
on 01 Sep, 2021 23:57
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Most recent and current electronics have internal surge protection and are pretty good if the surge comes through the power. However I have seen the internals of electronics charred between the network/coax/phone connection and the power ground enough to always advocate for a full suppressor close to the equipment. There is no downside to having lots of surge suppressors all over the house/building. Just be sure to connect the network cables through them.
There is a downside, if not a major one. Most surge protectors are based on MOVs, and MOVs can fail such that they conduct enough to heat up but not enough to blow the fuse. I've seen surge protectors melt down more than once, and I've seen pictures of some that have caught fire. At a former job we had a loose neutral at the transformer in the parking lot at one point that resulted in an imbalance that caused the MOVs in a UPS to catch fire, it was caught and doused pretty quick but it still burned a hole in the carpet. More surge protectors means more potential ignition sources.
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#34 Reply
Posted by
Monkeh
on 02 Sep, 2021 00:01
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Most recent and current electronics have internal surge protection and are pretty good if the surge comes through the power. However I have seen the internals of electronics charred between the network/coax/phone connection and the power ground enough to always advocate for a full suppressor close to the equipment. There is no downside to having lots of surge suppressors all over the house/building. Just be sure to connect the network cables through them.
There is a downside, if not a major one. Most surge protectors are based on MOVs, and MOVs can fail such that they conduct enough to heat up but not enough to blow the fuse. I've seen surge protectors melt down more than once, and I've seen pictures of some that have caught fire. At a former job we had a loose neutral at the transformer in the parking lot at one point that resulted in an imbalance that caused the MOVs in a UPS to catch fire, it was caught and doused pretty quick but it still burned a hole in the carpet. More surge protectors means more potential ignition sources.
That's why all good equipment standards (should?) require thermal fusing.. I haven't seen a MOV without one in anything made recently.
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#35 Reply
Posted by
tkamiya
on 03 Sep, 2021 03:39
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Apopka, Florida here.... (near Orlando)
I don't unplug anything during storms. My house has a whole house surge protector at service entrance, lots more ground rods than code calls for, another surge protector at breaker panel, then few large rack mount UPS that feed my whole thing. I had no equipment loss in last 30 years.
I once lived in an apartment. Had a full size CB whip on balcony. Much lower than roof level. Apparently, I got an indirect hit. The antenna's tip was melted. Thick aluminum angle mount at bottom had major chunk blown away. Lost TV, stereo, modem, and few other things. Funny thing was, VCR lived.
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#36 Reply
Posted by
1audio
on 08 Sep, 2021 05:28
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Current UL approved surge protectors have thermal cutouts that are tested by UL to confirm they will disconnect the MOV's when the voltage misbehaves. That problem is the main cause of MOV failure not lightning surges. In normal use they don't degrade. If across a big motor's brushes it might be a different story.
However products do not need UL to sell in the US except in a few places. And its not unknown for fake approved products to land in the market.
Open neutrals is more common than anyone would think. Often in modular offices. It can be insidious since many products will still work and sort of balance the 220 to have around 110 on each leg. You don't know until some of the loads are off that its a problem.
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I do disconnect my gear during storm.
1. I own a lot of unique instruments and i want to save them. They are divided into two groups connected to two separate UPS devices.
If someone only has a only TV and a fridge he may not be as concerned as i am.
2. In my first job as a UPS service man, we were receiving a lot of devices after severe storms. Mostly replacing MOVs but occasionally worse 'deep' damage.
3. It is strongly dependent if you live in a village at the end of a grid or you live in a densely populated city area.
Presumably the energy of a lightning gets divided into more nodes in the second case so chances that your surge arresters will do their job increase.
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#38 Reply
Posted by
mansaxel
on 08 Sep, 2021 07:02
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Open neutrals is more common than anyone would think. Often in modular offices. It can be insidious since many products will still work and sort of balance the 220 to have around 110 on each leg. You don't know until some of the loads are off that its a problem.
Oh. Another. Say after me:
In single phase AC, there is no practical difference between phase and neutral in safety terms.
Always assume both are live and you too, shall live. 
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#39 Reply
Posted by
Gyro
on 08 Sep, 2021 08:32
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There is a nice article in this 1984 issue Wireless World, which covers an investigation of a direct lightning strike on a church.
https://worldradiohistory.com/UK/Wireless-World/80s/Wireless-World-1984-10.pdfSome nice observations on what happens at the bends in the copper strap from the lightning conductor, the distance it jumped to the internal mains wiring in the tower. The standing wave effect that cause the mains wiring to 'disappear' at certain intervals, and the strike current, based on the earth stake resistance!
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#40 Reply
Posted by
Zucca
on 08 Sep, 2021 11:37
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Why nobody already mentioned the SPD 1,2 and 3?
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#41 Reply
Posted by
Jan Audio
on 08 Sep, 2021 15:23
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Lighting can hit you from somewhere else.
If there is storm around your town, you better unplug.
If i hear thunder eveybody laughs at me that nothing will happen.
People act like everything is replacable if something happens.
Yes you can download a digital equalivent for everything on your phone, i know.
My opinions on this:
If your house is susceptible to being struck by lightning directly, then you need lightning rods at least. I used to live in a house near the top of a ridge and we had them on all the roof peaks.
It can hit somewhere else and go thru the power line to your house.
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#42 Reply
Posted by
guenthert
on 08 Sep, 2021 16:43
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[..]
My opinions on this:
If your house is susceptible to being struck by lightning directly, then you need lightning rods at least. I used to live in a house near the top of a ridge and we had them on all the roof peaks.
It can hit somewhere else and go thru the power line to your house.
Different means for different risks. The surge protectors are meant to prevent the attached appliances from being destroyed, the lightening rods are meant to protect the house from burning down.
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#43 Reply
Posted by
tkamiya
on 08 Sep, 2021 17:04
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For even better protection, you'll need to protect from near by hit traveling via ground, too.
I was given a design diagram for lightening protection system at work. (2 floor concrete large building). Lightening rods at certain interval, ground wires completely surrounding the building in ground, ground rods every few feet, bus bars and connection to main electrical panel.... It's not something someone can casually do.
Also, grounding on regular housing is extremely poor. At most places, builders can install 2 grounding rods and call it done. Also, ground wire in house hold wiring is very neglected. I've seen someone just stuck in ground wire into a screw hole (without screw). Ground connections with just twisted wires are common, too. (without wire nuts).
Surviving direct hit without damage is possible. Empire state building in US get hit over 100 times a year, according to something I read. Cellular base antenna towers get hit on regular basis. Of course, they don't unplug anything.
I have an ongoing plan to add a room to my house for lab use. This thread made me think about all this. Thanks to OP for bring it up.
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#44 Reply
Posted by
David Hess
on 08 Sep, 2021 17:55
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To install a ground rod for the masts attached to my chimney, I attached a water hose to a 10 foot length of 1/2 inch copper water pipe to hydraulically drill it into the ground. The original ground rod at the line power hookup is pretty wimpy in comparison.
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#45 Reply
Posted by
Larryc001
on 09 Sep, 2021 22:55
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Some very good information in this discussion. The worst lightning I ever saw was around New York City. I guess the tall buildings with lightning rods on top may provide a lot of protection. I grew up on the prairies, lightning was very bad there I guess due to the flatness. Scary stuff when it is that close. Remember when your telephone was on a land line? Where it entered the building the first thing it was connected to was a lightning arrestor. However the worst electricity disaster I ever experienced wasn’t from lightning. The power company was replacing a power transformer in our neighborhood and hooked it up backwards! Needless to say the step-down transformer worked equally well as a step-upper. When they switched the power on it blew every electrical device in the neighborhood. Appliances which were on like the microwave just exploded. It was fortunate that nobody was killed or injured and no houses caught fire. They did reimburse affected customers but I can’t remember how long it took or how much they paid. I don’t think the percentage was very high. I have whole house protection as well as units protecting TVs, computers etc. But a agree nothing can provide 100% against Mother Nature.
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#46 Reply
Posted by
DaJMasta
on 10 Sep, 2021 01:47
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I'm surprised so many people unplug, but I wonder if just the grids that I've been on have been made to be somewhat better at dissipating surges or mitigating risk. In all my years I've never seen a piece of consumer or industrial gear on a home power connection get cooked by a lightning strike (though I've seen lightning take out a transformer on a pole across the intersection and we get heavy lightning with power loss yearly).
My stuff is on surge protectors, but I've never once unplugged it for a storm. Computers and consumer stuff included. I have really only lived on municipal power networks that seem to be maintained reasonably, but even at my current location with above ground lines and now three notable outages in the past year from storms... no tripped breakers, GFCIs, surge protectors and no damaged equipment. I assume a direct hit to the house would definitely be bad, but I at least haven't seen hits to nearby poles or substations to have any impact on the home power connection aside from knocking it out for a while.
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#47 Reply
Posted by
Neper
on 10 Sep, 2021 10:58
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Remember when your telephone was on a land line? Where it entered the building the first thing it was connected to was a lightning arrestor.
I remember the days when there was a note in the phone book advising people not to make phone calls during a thunderstorm. And no, that wasn't before WW2.
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#48 Reply
Posted by
MathWizard
on 10 Sep, 2021 12:05
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This reminds of another reason to get a laptop, or a backup battery for my PC. It gets really boring in my house if I don't have the computer going. Especially if it's payday or the weekend when I lose the power or want to unplug for a storm.
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#49 Reply
Posted by
Jan Audio
on 10 Sep, 2021 12:35
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I rather watch the lighting then a computer screen, rarity.