Why thunder damages lan port of pc and tv cable adapter?

Thread Starter

jraju

Joined Jul 23, 2017
91
It was a week ago. The climate was cloudy, when all of a sudden there was a lightning and a deafening sound of thunder. It was as if the thunder struck near my house.
I was viewing tv and the cable signal stopped and the power adapter to the set top box has gone.
Similarly the Lan port on my computer goes off, giving no internet access, as the Ethernet light not glowing in the modem/router. I tried reset but still could not get the Ethernet light on the modem.
My query is , how it damages selective ports in some devices.
My neighbour has lost his tv, and set top box totally in the impact.
Is there anything I could do avoid this .
The TV and the set top box adapter have been connected thro the stabilizers
 

SamR

Joined Mar 19, 2019
4,485
The problem is lightning at from 40kV - 120kV per stroke. Thunder is the noise generated by the supersonic lightning stroke. That is a LOT of electromotive potential which gets induced into any nearby metal including your house wiring and the conductors leading to the house. To help ameliorate the damage we use surge suppressors. Both at the main panel and also for each device that may need protection by use of a suppressor at the panel and a surge protector power strip for the devices that need protection. The surge suppressors will drain the excess induced and damaging voltage down to the house voltage to hopefully prevent any induced overvoltage damage.
 

Thread Starter

jraju

Joined Jul 23, 2017
91
Is it not normally done during electrical wiring work?
I am having a earthing done properly at the main panel . Is that not enough?
I also wish to state that both devices are connected to power inverter.
Is that a possible cause.
what is surge suppressors, please
 

SamR

Joined Mar 19, 2019
4,485
No, it is not normally done during initial construction. Unless, as I did, it is put into the construction requirements. As to what it is it can be, an Air Gap device that arcs over on overvoltage to ground. Or, more typically, high voltage metal oxide varistors that do basically the same thing. Bing is your friend... (1) panel surge suppressor - Bing images They have become a bit more specialized and sophisticated than the one I installed on our main panel ~40 years ago. And I have had lightning strokes ~20' from the house and not had any damage to our electronics which are substantial these days. At the very least use surge suppressor power strips which are also needed even with a main panel suppressor as the overvoltage can be induced in the house wiring after the main panel. A bit of a belt and suspenders approach but cheap compared to the damage that can occur without them.
 

nsaspook

Joined Aug 27, 2009
10,679
Is it not normally done during electrical wiring work?
I am having a earthing done properly at the main panel . Is that not enough?
I also wish to state that both devices are connected to power inverter.
Is that a possible cause.
what is surge suppressors, please
The usual villain is a ground potential difference between the CATV ground (or external communications cable) and the house electrical ground during a strike. It's a sneak-path that's toasted lots of equipment over the years as the potential voltage discharges from the elevated ground potential of the isolated cable into the signal path of computers and receivers . Every ground reference (cable shield) needs to be a the same equal potential bonding point so they can rise and fall together. Communications cabling grounding blocks (a NID for digital cables) with surge suppression need to be installed outside the home/facility with a direct connection to the electrical system grounding point outside to provide a direct shunt path for electrical energy.
https://www.polyphaser.com/Themes/P...ges/2020_TTR_PP_Surge_Protection_Brochure.pdf


https://www.varia-store.com/en/prod...evice-esd-protection-and-grounding-point.html
https://tiitech.com/nids/enclosures/


https://www.ppc-online.com/blog/bonding-and-grounding-for-catv-whats-the-difference
https://www.polyphaser.com/search?Category=RF+Surge+Protectors&sort=y&view_type=grid
 
Last edited:

nsaspook

Joined Aug 27, 2009
10,679
I think the "stabilizer" is used in a far way country because the electrical voltage is not regulated as it is in Western countries.
Also, far away countries still have electrical wiring up in the air between poles but Western electrical wiring is usually underground.
Yes, I've used many a line stabilizer overseas in the house. It's usually a auto-transformer with a simple auto tap switcher. The provide zero protection from lightning surges but it will keep the AC running during the daily power brown-outs.
 

ronsimpson

Joined Oct 7, 2019
2,523
My query is , how it damages selective ports in some devices.
It seems that all your things are connected to ground. There is the power company/house power ground. The cable company has a ground. The phone company has a ground. Maybe there is a different wire for internet with its ground.
When lightening hits there could be 10000Volts difference between grounds for 1uS. (or 1mS) You set top box sits inbetweener two different grounds.
There can be large differences between the grounds in one room to the next room.
In the news they showed a picture of lightening exiting a bathroom light fixture and jumping to plumbing pipes. There had to be some serious voltage differences between (power & ground) compared to (plumbing & ground) to jump 4 feet.
 

Reloadron

Joined Jan 15, 2015
7,079
I can share this. Long ago when people were using phone line modems the house next door to my sisters too a direct lightning hit. My sister's computer by some miracle only lost the dial up modem card and also lost a few of her wired phones. Her neighbor lost everything and anything plugged in. You can figure things this way. You can buy all sorts of lightening arrestor devices and many will work to some extent. However in the path of a direct lightening strike anything and everything will be toast. Years ago, I believe it was a member here had a home surrounded by large tall trees, trees extending higher than their house. The chimney took a direct hit. The hit produced super heated steam and the bricks in the fireplace exploded. Surge protectors are not a guarantee of magical protection in the path of a direct strike.

Ron
 

SamR

Joined Mar 19, 2019
4,485
I had a HAM buddy from upper NY whose house got hit. It went through the roof, through the kitchen ceiling and floor, and into the basement floor. Not following the house wiring or structure at all. It is sneaky and hard to predict. Like the clear sky lightning they get in Florida on a sunny day. As they say, The only thing that will protect you from lightning is to hold a 1 Iron over your head. Because, Not even God can hit a 1 iron but sometimes even he gets lucky! That's why they call it suppression and not prevention.
 

Reloadron

Joined Jan 15, 2015
7,079
Long, long ago when wife and I were dating we were in a large park system which surrounds Cleveland, Ohio (The Emerald Necklace), Severe thunderstorm rolled through and we hopped into the truck. Flash bang of a lifetime hit a tall tree. Sounded like a long string of firecrackers. Storm passed and tall tree was reduced to a few million toothpicks. Never saw anything like it and contrary to much belief lightening is not at all predictable. :)

Ron
 

SamR

Joined Mar 19, 2019
4,485
I was on the computer one day when a tall pine tree just outside the house was hit. A huge explosion which startled me so badly it lifted me up off the chair. About the time my butt came back down into the chair it hit again. Double stroke. Sorta rare but they do happen. Tree wasn't splintered but had a 6" strip of bark blown off down the length of it. A few upper limbs died quickly but that tree did not survive and it was a BIG heart pine around 3' in diameter.
 

Reloadron

Joined Jan 15, 2015
7,079
Lightning hit the neutral on the supply pole.
A few takeaways on the damages done. If I had all that data of importance on a home computer I would be backing it up daily to a NAS box or similar and if I had a prior lightening experience my backup device would only be connected during backup times and never during storms. Even an external HDD would work. Just disconnect whatever you use when not in use and always during severe weather. I can't imagine a business less backup. Especially in a wide open area prone to lightening strikes.

I had a little MiFi for my Internet backup when I had Verizon and now my smart phone serves as a hot spot when we lose internet. It works well. Wife has the same phone just in case.

Ron
 

Thread Starter

jraju

Joined Jul 23, 2017
91
From all the answers and comments, it seems that nature is super powerful and it is not possible to predict, how it affects different devices differently.
As one says, it was a sunny day, when all of a sudden a lightning and thunder struck in this month in my place.
During casual conversation, i heard so many houses has lost different devices totally damaged in the impact.
compared to their losses, my loss seems to be minimum and nearby houses experienced tv just became black screen, led lights fused, and fac become not operational.
Earthing is the only way to get minimum damage, I think
 

MisterBill2

Joined Jan 23, 2018
13,740
Indeed, nature is super powerful." With half a million volts, or so, and 100,000 amps, lightning will go wherever it chooses.
T have any sort of adequate protection for a computer, a wireless link to a modem is a safe choice, along with internal battery power for the computer.
Any wired connection is subject to the will of the high voltage generated by that high current flowing through the resistance of whatever path it follows.
Consider that 100,000 amps through one ohm produces 100,000 volts.
 

MrSalts

Joined Apr 2, 2020
2,599
From all the answers and comments, it seems that nature is super powerful and it is not possible to predict, how it affects different devices differently.
As one says, it was a sunny day, when all of a sudden a lightning and thunder struck in this month in my place.
During casual conversation, i heard so many houses has lost different devices totally damaged in the impact.
compared to their losses, my loss seems to be minimum and nearby houses experienced tv just became black screen, led lights fused, and fac become not operational.
Earthing is the only way to get minimum damage, I think
There are some areas of the US where there is very little soils but rocky / gavel hills. Without the moist soil around the whole grounding rod, there is no good connection to "ground".
 

nsaspook

Joined Aug 27, 2009
10,679
There are some areas of the US where there is very little soils but rocky / gavel hills. Without the moist soil around the whole grounding rod, there is no good connection to "ground".
We would 'salt' the grounding system to improve grounding performance. Back in the day the transmitter station at KW was built on coral. The chemicals used for the ground planes still create dead-zone circles decades later.
https://www.google.com/maps/place/S...698938674bc31c!8m2!3d24.6483528!4d-81.5736265

https://www.google.com/maps/@24.630...347.46045&pitch=0&thumbfov=100!7i13312!8i6656
 

Reloadron

Joined Jan 15, 2015
7,079
There are some areas of the US where there is very little soils but rocky / gavel hills. Without the moist soil around the whole grounding rod, there is no good connection to "ground".
Been there and played that game. About a year before I retired it was decided we needed a new sub station for our facility. I was sucked into that nightmare. Well not a nightmare for a facilities engineering type which I wasn't. I did get a crash course in power sub station ground planes and ground in general. The actual work was contracted out. This is a pretty good read on the subject. We started with soil analysis drilling out soil core samples which are sent to a lab. Then you drag in a backhoe and start building an "earth mat" with a mountain of copper bar stock. Once you create all of this you fill in the hole and built your sub station on your hallowed ground. Lightening arresters come later. :) We buried plenty of copper.

We only brought in 13.3 KV. The option for 25 KV was also on the table. Buying 25 KV service is a little lower cost than the 13.3 KV but the 25 KV switchgear has a much higher cost. I was looking at a 20 year cost turn around so went 13.3 KV.

While none of this has much anything to do with residential lightening it is interesting and amusing. :)

Ron
 
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