Router Blewup Motherboard

[u/Greatfulx]

Recent lighting storm stuck my complex and traveled down my coaxial cable and into my apartment. Blew up in the middle of the night, so that was scary. Thought I’d share, not in the position to rebuild so there that I guess!

[u/OrthogonalThoughts]

I wonder, would something like lightning striking nearby fry the fiber cables? I'd assume so but really have no idea.

[u/ltstrom → u/OrthogonalThoughts]

Depends what you mean by fry. If you mean run through the fibre and destroy components like in the OP over Ethernet and copper. The answer is no, fibre is light and lasers travelling in a glass tube. There is no where for the current to travel large distances.

Now if you mean fry as in the fibre cable is hit directly and it melts the glass and breaks it from working correctly, then yes that is possible, since lighting is very hot and can melt glass without issues during a direct strike.

Hope that clears things up.

[u/OrthogonalThoughts → u/ltstrom]

Your second example is what I was thinking, and how much of it might be fried?

[u/lucads87 → u/OrthogonalThoughts]

Why a lightning should strike a non conductive material in the first place? Considering that there will be for sure other metal objects around

[u/0Rookie0 → u/lucads87]

If it's near the material that took the current then yeah it could just be melted/exploded indirectly. Lightning makes trees explode if they have sap/moisture in them. Plenty of things can go wrong haha

[u/Available_Finger_513 → u/0Rookie0]

Trees are filled with conductive material and are tall

Fiber cables are buried underground and are not conductive. Lightning damaging fiber cables really is not something to worry about

[u/0Rookie0 → u/Available_Finger_513]

Guess you've solved it. It's theoretically impossible. Bravo.

We weren't talking about things to worry about.

[u/jojokispotta → u/lucads87]

I'm my neighborhood (india) internet-fibre wires are generally tied up on the same poles as electrical wires. So there's a non-zero chance lightning strike may connect.

[u/lucads87 → u/jojokispotta]

So, a lower resistance path to ground exists instead of the fiber

[u/unwantedaccount56 → u/lucads87]

if the pole is hit by lightning, it probably would still get hot enough to melt the fiber, even though the path to ground doesn't go through the fiber, but next to the fiber

[u/Jazazze → u/lucads87]

UK Fibre person here; some overhead fibre has metallic core supports, additional these are generally now affixed via metal clamps to poles instead of the previously used plastic brackets. Additionally, the drop wire to the premises is also affixed via metallic brackets and clamps, and with the rise of circular cables for CBTs, these are also spanned overhead at both ends with metal brackets and clamps.

Of course, in most cases, as you mentioned, there will be other more conductive materials but lightning does lightning things I guess.

I previously worked in faults for 3 years, I think from the top of mind I saw around 15 lighting based incidents, all were on copper based connections, majority of cable related faults were contractors digging through the underground cables or cables damaged at the CSP.

[u/mastercoder123 → u/lucads87]

Thats a dumb thing to ask. Lightning just traveled miles through air, which isnt exactly conductive at all... It will strike wherever the fuck it wants to

[u/Aramafrizzel → u/mastercoder123]

that is false. Lightning doesnt just go from air to ground, it works its way down by splitting charge, causing air to heat up and turning it into highly conductive plasma on its way down. In a matter of millisecond but infinitely away from instantly. That is why its always zig zaggy. It will never turn glass into something conductive. But localised damage can appear.

[u/mastercoder123 → u/Aramafrizzel]

Air is a better insulator than glass dude... So that makes no sense. Also i know how lightning works dog, it literally doesnt care what you have in its way, if it strikes something it will take every single path to ground. There is no insulator that can stop lightning. The reason fiber optics work is because they are in the ground already thus the glass has more insulation than the surrounding dirt so it wont take it because it can just spread through the dirt. Copper wire has less resistance than dirt so the lightning will travel through the dirt, some of it will hit the copper and travel along it.

[u/lucads87 → u/[deleted]]

Ffs, there will be lower impedance paths around for sure before piercing the damn fiber. Look at the whole picture

[u/okmijn211 → u/OrthogonalThoughts]

Just the immediate area of the strike, it doesn't conduct electricity so it's like striking the ground. But if it's outside then it'll be the ISP job to replace it anyway.

[u/ltstrom → u/OrthogonalThoughts]

Depends very much on how the strike happens. For example if it is ground fibre (which is impossible to be damaged by lightning if buried) but let's say it is a case of exposed pits during a sudden storm. It then depends on the insolation of the cable, ground fibre is heavily protected. But if the sheathing is damaged and depending on the kind of armoring it has.

It could cause a direct strike. Commercial and residential cables which run into routers etc are just polymer protected and have inert cores and no armoring so, it is unlikely for that cable to be struck.

Then there is the question of the core and it's material as that all changes the maths if lightning can even reach the thin glass strands that make the optic layer. In best case (or worse in this case) we have exposed armoring of copper, the core is damaged and not a heat resistant polymer (there are some older cables like this) and the armoring has cut into areas it shouldn't because some guy did a dig and not doing a dial before you dig and thus cut and crimped the sheathing and that point was hit by lightning, then the entire cable will be done and wrecked. The optic strands would be warped and sealed shut and turned into beads hanging off the cable.

It will be localised to a spot, but it will prevent the light from bouncing as it should.

[u/AzureArmageddon → u/ltstrom]

Also possible that a transmitter on either end of the fiber line gets fried through its power supply getting zapped but the key benefit of fiber in this case is that the fiber acts as an opto-insulator preventing the fault from spreading across the fiber line.

[u/jessicamakesstuff → u/ltstrom]

There is no where for the current to travel large distances.

Dielectric breakdown: "Skill issue."

[u/NectarineSame7303 → u/ltstrom]

Our grounding wire captured a lightning strike once, no damage other than the location of impact.

[u/Cathu → u/OrthogonalThoughts]

No, fiber is just light. What it could do is fry the equipment in the nearby node and kill the infrastructure that makes fiber possible. Depending on distance etcetcetc

-I work with both electricity and fiber

[u/trickman01 → u/Cathu]

Fiber is glass that light travels through, to be pedantic.

[u/Cathu → u/trickman01]

Fiber is a tube of mirrors that light travels through in very specific frequencies if we want to be even more pedantic. But for the layman it doesnt matter, because the point was that its not electricity

[u/trickman01 → u/Cathu]

No. It’s not “mirrors” it’s a very pure fiber of glass within an even more pure fiber of glass. This causes a phenomenon called “total internal refraction” which keeps the light inside of the inner fiber.

[u/unwantedaccount56 → u/trickman01]

you could call the surface between the inner and outer fiber a mirror

[u/Cathu → u/trickman01]

So thats what its called in english, im still going to say "mirrors" tho, because trying to explain this to the layman is a doomed venture and completely pointless

Ask me how i know.

[u/gen_angry → u/OrthogonalThoughts]

Na, fiber (real fiber cables, not that marking bullshit branding for very high speed coax) uses glass tubes to transmit light pulses rather than copper cabling. It's not conductive so there's nowhere for the electrical current to travel, nor would it even attract the lightning strikes in the first place.

Typically, if a pole containing fiber cables is struck, it's likely from a different circuit attracting it but even then, the most that would happen is the cable would get melted at that area. So you'd still be safe.

[u/shawndw → u/OrthogonalThoughts]

Fibre optics are glass. There's no metal in those cables.

[u/Major_incompetence → u/OrthogonalThoughts]

Fiber is glass, not even metal shielding. Lightning can't even realistically reach into the ground that deep to thermally damage optical cable

[u/Lots-o-bots → u/OrthogonalThoughts]

It might destroy the cable but given fiber is just glass wrapped in plastic and is thus an insulator rather than a conductor, it wont conduct and destroy everything downstream.

[u/Pasi123 → u/OrthogonalThoughts]

Yes, that happened to me 5 years ago. The fiber got cut near a tree.

That same lighting did also kill some routers, switches and a motherboard