Lightning strike enters apartment through coaxial internet cable, blows up gamer's PC — surge causes extensive damage to motherboard, destroys router, and leaves burn marks on the wall
Internet cabling turns into a conduit.
A lightning strike has reportedly turned an internet connection into a destructive pathway for thousands of volts, leaving behind a damaged router and PC motherboard. The rare incident was shared on Reddit by user u/Greatfulx, who claims that during a recent thunderstorm, lightning entered their apartment complex through its coaxial cable infrastructure before damaging their network equipment and desktop PC.
According to the shared photos, the Ethernet port on their PC appears to have suffered extensive damage, leading them to believe the surge traveled from the router into the PC via the Ethernet cable. Notably, the damage on the motherboard appears to be concentrated around the Ethernet port rather than the entire board. While most modern Ethernet ports include surge protection designed to shield devices from electrical faults, an extremely high voltage power surge can potentially overload such safeguards. Additionally, the photos showcase the damaged router alongside large burn marks on nearby walls and the coaxial cable outside the apartment.
Router Blewup Motherboard from r/pcmasterrace
"Recent lighting storm struck my complex and traveled down my coaxial cable and into my apartment. Blew up in the middle of the night, so that was scary," the user wrote. "Thought I’d share, not in the position to rebuild so there that I guess!" The user told onlookers in the comments they were chasing up parties over possible negligence after one user pointed out a grounding/earthing attachment outside the building didn't appear to be connected properly.
The incident draws parallels to similar lightning-related hardware damage stories shared on Reddit. In one case, a user reportedly lost internet connectivity after a loud thunderstorm and initially assumed the issue was limited to their network connection. After some inspection, they discovered that the motherboard's dedicated LAN protection component, branded as "LAN Guard," had reportedly detached from the board. The user claimed that a surge possibly traveled through the Ethernet connection and was absorbed by the protective circuitry, potentially preventing more extensive damage to the rest of the PC. A similar lightning-related incident was shared by a user on Reddit who reported that a thunderstorm damaged their PlayStation 5’s Ethernet port while the console was connected via a wired network connection
Such incidents highlight a common vulnerability that is overlooked in most home electronic setups. While many users protect computers and other components with surge-protected power strips or uninterruptible power supplies (UPS), surges can enter through network and communication lines as well. If a lightning strike enters through a coaxial cable, modem, router, or switch, the resulting electrical energy may bypass protections designed primarily for AC power outlets.
Although no consumer-grade protection device can guarantee safeguard against a direct lightning strike, it is highly recommended that coaxial lines are properly grounded and that the use of surge protection for both power and data connections is used where possible.
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Kunal Khullar is a contributing writer at Tom’s Hardware. He is a long time technology journalist and reviewer specializing in PC components and peripherals, and welcomes any and every question around building a PC.
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bit_user LOL, this is why I have my cable modem on a separate UPS. Then, the Ethernet cable goes through a grounded Ethernet surge protector to connect to my router, which is on the same UPS as my main PC setup. And everything that's electrically connected to my PC is plugged into the same UPS that it's on, including my audio system.Reply
I think this is the one I bought, quite a while ago. It seems to pass a 2.5 Gbps signal just fine:
https://www.amazon.com/dp/B00805VUD8
It's grounded to the UPS which the cable modem is plugged into. -
TechieTwo Lightening can follow any electrical path and cause damage. I once experienced leghtening hitting a 120v wall outlet circuit blowing the recepticle right out of the box.Reply -
bit_user Reply
Yeah, depending on how close the strike is, there might be nothing you can do. However, the law of probability says that most lightning-related power surges will not be that close. In which case, the level of precaution taken can make all the difference.TechieTwo said:Lightening can follow any electrical path and cause damage. I once experienced leghtening hitting a 120v wall outlet circuit blowing the recepticle right out of the box. -
dwd999 The unanswered question is whether or not the computers were on at the time of the strike. When I had my strike in 2017 my computer was off, so the strike only blew out my cable modem and router, didn't go down the lan cable. No big deal; but it also blew out my garage door opener and the circuit board in my furnace. Those were expensive!Reply -
kanewolf Reply
Lightning is scary stuff. When our house was hit (antenna), it exploded the braid on the coax all the way to the pole. It put a burn mark on the house where the coax was run. It MELTED the ground wire for the antenna. Something (EMP, static, ????) killed an HP41 calculator which was not connected to anything. It fried motors in the AC unit. If it hadn't been raining so hard, the house would probably have burned down from the fire started where the guy wires were attached to the house.TechieTwo said:Lightening can follow any electrical path and cause damage. I once experienced leghtening hitting a 120v wall outlet circuit blowing the recepticle right out of the box. -
USAFRet Reply
And that does not always help/prevent.bit_user said:LOL, this is why I have my cable modem on a separate UPS.
Lighting strike in my backyard a few years ago:
Industrial surge protectors and UPSs.
UPS/surge protector 1:
PC, 3D printer, 3 monitors, 4 port switch.
Killed parts - Ethernet port on the PC motherboard
UPS/surge protector 2:
NAS, TV, cable box, AV receiver, laserjet printer, a few other things.
Killed parts - HDMI port in the AVR, ethernet port in the printer
UPS/surge protector 3:
PC + 2 monitors
Nothing killed.
Other weirdnesses:
Unused and unplugged Invisible Fence control box. The cover was blown across the garage
Battery powered laser level. Was OFF. In the middle of a room upstairs, on a tripod.
Voltage/EMP through the air apparently turned it ON. -
Gururu Not terribly worried about the fiberoptic feeding my service, but I guess the old coax lines running along house siding is risky. Kind of second guessing my ONTs which are connected to my router.Reply -
USAFRet Reply
My service coming into the house is fiberoptic.Gururu said:Not terribly worried about the fiberoptic feeding my service, but I guess the old coax lines running along house siding is risky. Kind of second guessing my ONTs which are connected to my router.
All the damage I noted above still happened.
Electricity follows whatever pathway it wants. -
Penfolduk When it's a lightning strike, or even a big surge along a power cable, even the most robust surge protection or UPS set-up won't always protect the hardware. My ADSL Line is surge protected.Reply
Guess it's back to the old advice with TV during thunderstorms - physically unplug the power and aerial (comms) cables.