I posted this question on AVS forum, but though I would see if anyone had any ideas here:
Last Friday we had a lightning storm & lost power when our transformer blew, our phone went dead too (juice was restored about 4 hours later, phone about 2 days later). All of my AV & computer equipment was fine except for my router and all the ethernet cards that were plugged into it.
I’m curious as to what could have fried the router & the best way to prevent this in the futre. Electric, phone & cable lines were run through a surge suppressor, so I have two theories:
1) The nearby lightning hit induced a current in our ethernet lines thus toasting the router & all NIC’s. I don’t know how likely this is, because I thought the twisted pairs were to prevent induced current. If I’m wrong on this, how would I prevent this from occuring again?
2) Either when the power went out or came on, there were some wide voltage swings that caused the router to give up the ghost & in the mean time send out some toastage to all NIC’s that were connected to it. (I bought a UPS the next day that had an automatic voltage regulator in case this was the problem)
Anyone else have any ideas? If it was an electrical surge (or a cable surge), I would have expected all my cable connections to be fried or my TV, PC & other AV equipment to be toast.
Replies
Not real sure what the problem was, I do know that electricity can do really wierd things and lightning loves anything with a coil in it, which is what most of the protectors are. By the way what AV forum did you post this question on.
Wade
I mistakenly said it was AVS, but it I posted it on the byopvr forum.
I suspect that the surge went through the cable. Had the nearly identical thing happen to us about 3 years back -- left the cable modem OK but took out the router and 3 of 4 network cards.
There are Cat5/whatever surge suppressors available, don't know how effective they'd be. Sticking a cheap (sacrifical) ethernet switch between router and the rest of the system may help prevent network card damage.
I'd be kinda surprised if it was #2. I don't know why a router would send out that much current along the ethernet lines.
I suspect that #1 is probably the answer. Lighting seems to be able to generate fields in pretty much any form of wire or cable. About the only thing I can suggest is to make sure your cable system is grounded, perhaps at a point near the cable modem, use a router ONLY for connecting from the cable modem to a switch, and run you LAN cables to the switch, and not the router. I use a Linksys router for the firewall, and I make one connection from the router to a switch, but the rest of the connections are to the switch.
If you find out anything more definitive, come back and post the results. I'm very interested in what you figure out.
Cause could be a number of issues. I avoid some of that by using WiFi, that way if anything hits the router it stops there and the rest of the computers are ok.
I also have the router in a good UPS and have never had an issue with power faults since then
Was it a plunge or fixed based router?
And how did it relate to the network problems? Did you get the cable wrapped around the bit? Next time don't route when there is lighting.
Seriously the answer is none of the abover or all of the above.
Lightning could have induced enough voltage in network cables and fried both ends.
A surge could have come in the power line or cable and the surge arrestors are not "perfect" (and if they where they would not allow the desired signals through) and a surge could have come in will not damage what it is connected to, but maybe equipment 2 or 3 componets later.
But here is what is more lightly happened.
You got a strong hit on the power line. The surge protector worked and dumpped 1000's of amps in to the ground. The power line AND GROUND jump up to 1000's of volts for a fraction of a millisecond.
However, because of different paths the ground on the computer equipment did not respond at all or not until a few microseconds later. So for that short time there was a large voltage different between the different componets.
We had a direct hit next door on the telephone pole.
It took out the cable modem, my router, my wireless base station, and the printer. The TV which was also attached to the same cable had no issues.
What irks me the most about that situation is that the week before I had the cable company out here to verify the connection (frequent drop-outs) and the tech told me to disconnect the Cable surge protector in the APC UPS since it was causing the signal to drop 4.5db (!!!!). Now defenseless, lightning had to strike!
I now route the output from the modem into the UPS (ethernet) before connecting to the rest of the house. That ought to limit damage in the future.