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Thread: Strange phenomenon happening to me - electric.

  1. #1

    Strange phenomenon happening to me - electric.

    Since July the internet modem in our house has gotten zapped 4 times.

    My BIL, who is a network technician, determined it is coming through the CAT5 cable which runs out to a wireless modem in my barn/shop. .

    Last time there was an apparent lightning strike very close that tripped the transformer fuse that feeds my shop + exploded (I mean exploded) an outlet box close the pole that feeds power to an automatic gate (which also got fried). That time the modem got fried.
    My BIL replaced the modem and also found a faulty junction in the line that was affected by the power surge. I have installed a grounded network surge arrestor, but last night it apparently didn't work.

    The weird thing that happened last night was a 40A breaker that feeds a subpanel in my shop was tripped.

    We have lived here for 29 years and I don't think we've ever had this happen once.

    All this has happened since I had 4 big pine trees removed in July.

    Is this just a fluke? Is there anything I can have my electrician check?

    Or are the tree gods taking their revenge?

    Do I need to install lightning rods (metal roof)?

    We thought it can't happen again, but from now on, we're unplugging the modem the first sound of thunder.

  2. #2
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    It would be strange that the network cable to the router/AP is causing electrical issues beyond it, but perhaps the cable is compromised and has connectivity to some other wire, either directly or indirectly. Lightning strikes can cause all kinds of weird things because of how powerful they are and how they can jump around between things that are even not directly connected. If your BIL thinks that the issue is centered around the network cable, perhaps it would be prudent to replace it...
    --

    The most expensive tool is the one you buy "cheaply" and often...

  3. #3
    Thx. Jim.

    Actually he already suggested that but didn't have time when he was here.

    The wire does travel partway along the metal electric conduit. Wonder if that could be an issue?

    The surge protector has a ground wire that runs to the outlet, which is, of course grounded to the metal box, and hence the conduit.

    The breaker controlling that outlet was not tripped.

    I'm thinking I should put a GFCI outlet in.



    Any idea what could cause the 220v breaker to trip?
    Last edited by Robert Engel; 09-11-2018 at 11:34 AM.

  4. #4
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    These kinds of problems can be really hard to track down....

    It would be simple for someone with an ohmmeter to check for continuity between any of the Cat 5 conductors and ground. If you end up replacing the cable, I suggest you use shielded cat 6 cable. The shield gets grounded (only on one end) and helps prevent electrical noise and surges from coupling into the signal conductors.

    If you don't have a lightning arrestor on your incoming cable line (for cable modem) or Telco line (for DSL) I would add that. Cable company usually installs one, but worth checking. Even if you have one, they can get blown so it would be cheap insurance to replace it. Surge suppressor on AC to modem would also be a good idea. Don't see a GFCI helping in this case.

    Note that unplugging the AC from the modem won't help if surge is coming in the cable/Telco line or the Cat 5 line.

    I would also check the grounding at your subpanel. If it was installed before code required ground rods to be installed at the outbuilding, I would add them there. And consider adding a hardwired whole house (barn) surge suppressor in the subpanel at the outbuilding.

    These are shotgun approaches, but often that's the only way to eliminate these kinds of problems.

    Not a big fan of lightning rods. They are really hard to install properly and when not installed properly they are likely to make the problem worse, not better.

  5. #5
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    I have worked in networking for 25 years. I would never run copper networking cables between buildings just because of problems like this. How far of a run is it to your barn? I would install a fiber optic media converter at your modem and then another at the wireless router in your barn. The cost for the gigabit converters seem to be around $40-$50 each on amazon. Since terminating fiber requires special tools I would just buy a long enough premade fiber cable and run it between the buildings. On amazon a 50 meter cable is $50, a 100 meter cable is $90 and a 200 meter cable is $160. So all in you are looking at ~$150 if your barn is <150 foot away. If you need help figuring out the right parts if you want to do this PM me and I can help you out. Good luck.

  6. #6
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    Where do you live, how common is lightening there? If it is something that will happen every few years or more I would consider adding a line filter(the proper name escapes me at the moment) to the line supplying the computer stuff.
    I mean the big isolation transformers. For most people back EMF from motors is more of a problem then lightening. I put one on my lathe that can handle 40? amps used for under $40 delivered. It will protect the vfd from any bad motor backfeed issues.
    Bill D
    Line reactor?

  7. #7
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    Quote Originally Posted by Chris Fairbanks View Post
    I have worked in networking for 25 years. I would never run copper networking cables between buildings just because of problems like this. How far of a run is it to your barn? I would install a fiber optic media converter at your modem and then another at the wireless router in your barn. The cost for the gigabit converters seem to be around $40-$50 each on amazon. Since terminating fiber requires special tools I would just buy a long enough premade fiber cable and run it between the buildings. On amazon a 50 meter cable is $50, a 100 meter cable is $90 and a 200 meter cable is $160. So all in you are looking at ~$150 if your barn is <150 foot away. If you need help figuring out the right parts if you want to do this PM me and I can help you out. Good luck.
    I think that you have a very good idea of getting rid of the copper between buildings. Fiber is a good solution. Wifi might be a stretch unless you used a gain antenna or an repeater/extender.

    The OP commented: "The surge protector has a ground wire that runs to the outlet, which is, of course grounded to the metal box, and hence the conduit. The surge protector "might" protect you against some minor surges but when lightning is involved, it is likely to be much more than it can handle. Also a ground wire that goes to an outlet that is grounded to the metal box might be very ineffective on a high-current fast rise-time pulse.

    I'm thinking I should put a GFCI outlet in." Go ahead, but it is unlikely to help very much.

    So I think that you, Chris, have given very good advice.


    (My house was hit by lightning twice - - really strange damage. Vaporized wiring, melted things, and things that failed a month, six months or a year later.) I was actually indirectly "hit" by lightning once - - there was about a 1" arc between some electronic equipment and me. Yikes !

  8. #8
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    If you're going to have to trench for a new cable, run a length of black polyethylene piping as a conduit to pull it in. Suck a mason's line through it by tying a little piece of cloth on the end, and use a vacuum cleaner. Any time in the future, when things change, or for whatever reason you need another cable, you'll be ready. Lightning can do some strange modifications for you.

  9. #9
    You have had one verifiable lightning strike. The damage from this will not always be immediately obvious. It seems you have stray currents reeking havoc on your electrical and low voltage systems. That lightning strike could be the culprit but where is hard to say. I've been on jobs where these poltergeists have resulted in the replacement of nearly every electronic device connected when the strike took place. Do some sleuthing. Pay close attention to devices directly involved with problems you are having problems with, or simply replace them. It takes time to weed out problems like this.

    The only way I can see the removal of pine trees being involved in the problems is if in doing so some overhead wiring connection loosened. Loose connections can create arcing. At first things seem to work fine but over time they usually worsen. With overhead wires, the movement of those wires can affect the loose connection, kind of like when your corded drill only works when holding it in certain positions. So maybe an overhead splice at the pole is faulty.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  10. #10
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    I will also note that I think you mentioned that your Ethernet connection is strapped to your electrical conduit. That says you have no physical separation between the low voltage and the high voltage lines. That's not generally a good thing and with the lightning strike potentially compromising the cable, it could be exacerbating any interaction between these two systems. "Best Practice" is for low voltage and high voltage to have a reasonable air gap between them...like 12" minimum. Changing the network line to fiber as has been suggested can help alleviate this, although some outdoor rated fiber cables also have metal reinforcement in them which can still have inductance potential.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  11. #11
    Quote Originally Posted by Julie Moriarty View Post
    You have had one verifiable lightning strike. The damage from this will not always be immediately obvious. It seems you have stray currents reeking havoc on your electrical and low voltage systems. That lightning strike could be the culprit but where is hard to say. I've been on jobs where these poltergeists have resulted in the replacement of nearly every electronic device connected when the strike took place. Do some sleuthing. Pay close attention to devices directly involved with problems you are having problems with, or simply replace them. It takes time to weed out problems like this.

    The only way I can see the removal of pine trees being involved in the problems is if in doing so some overhead wiring connection loosened. Loose connections can create arcing. At first things seem to work fine but over time they usually worsen. With overhead wires, the movement of those wires can affect the loose connection, kind of like when your corded drill only works when holding it in certain positions. So maybe an overhead splice at the pole is faulty.
    Underground service. All other electronic devices (chargers, window ac's) working fine.

    BIL coming out Sat. Plan is to replace the entire run of network cable & use a surge protector (duh!) that also has plug ins for network. The wireless router in the barn will power up, but there is no internet connection, so I'm thinking maybe the network cable is fried.

    Which is making me think the surge is coming through the network cable, NOT the electric supply.

    I think fiberoptic is going to be too expensive right now. Like I said, the really weird thing is we've had this exact set up for 4 or 5 years with no issues until this year. We just put the 4th replacement modem in since July when I cut the trees.

    Would plugging into an outlet on a different circuit be advisable?

    And does anyone have any idea why the 220v breaker was tripped? I checked everything yesterday and couldn't find anything.

    There are two pecan trees on each end of the barn. Couldn't find any evidence of a strike.

  12. #12
    Quote Originally Posted by Robert Engel View Post
    Underground service. All other electronic devices (chargers, window ac's) working fine.
    On one job the 480v man lift wasn't working the morning after a storm. I checked the three legs and got 277v on all of them. Turned out the 24v controller was fried. Little things always seem to go first.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  13. #13
    Quote Originally Posted by Robert Engel View Post
    And does anyone have any idea why the 220v breaker was tripped? I checked everything yesterday and couldn't find anything.
    I'll give it a shot but I need some more info...

    "Last time there was an apparent lightning strike very close that tripped the transformer fuse that feeds my shop + exploded (I mean exploded) an outlet box close the pole that feeds power to an automatic gate (which also got fried). That time the modem got fried."
    By transformer fuse, do you mean at a pole mounted transformer feeding your shop?

    "My BIL replaced the modem and also found a faulty junction in the line that was affected by the power surge. I have installed a grounded network surge arrestor, but last night it apparently didn't work."
    You mean it didn't work because the 40A breaker tripped or is there something I missed?

    "The weird thing that happened last night was a 40A breaker that feeds a subpanel in my shop was tripped."
    When the transformer fuse blew, was that 40A breaker tripped? If so, did you replace it? Were any other breakers tripped and did you replace any of them? Have you checked the other loads in the shop for anything unusual, like not running like they used to?

    If you have an amp probe, turn off all the breakers in the sub-panel and check to see if you get any readings on the legs at the 40A breaker. Then check the voltage coming into the shop and compare it to the line (at the main panel or however you are feeding the shop panel.) You're looking for leaks in the feeder cables.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  14. #14
    Quote Originally Posted by Julie Moriarty View Post
    I'll give it a shot but I need some more info...

    By transformer fuse, do you mean at a pole mounted transformer feeding your shop?
    Yes. That time was the first incident. Loud strike real close. Nothing was affected except the outlet box near the pole, and the modem.

    We've lost the modem 3 more times since then. And none of those did we hear a really close lightning strike, just some loud thunder.

    You mean it didn't work because the 40A breaker tripped or is there something I missed?
    Totally separate incident. The modem didn't work because there was a fault in the network line. At a junction connector, you could see scorch marks. So that tells me high voltage got into the CAT5 cable.

    When the transformer fuse blew, was that 40A breaker tripped? If so, did you replace it? Were any other breakers tripped and did you replace any of them? Have you checked the other loads in the shop for anything unusual, like not running like they used to?
    No, separate incident as I said above. The only breaker tripped was the 4th incident. The 2nd & 3rd just involved the modem.

    If you have an amp probe, turn off all the breakers in the sub-panel and check to see if you get any readings on the legs at the 40A breaker. Then check the voltage coming into the shop and compare it to the line (at the main panel or however you are feeding the shop panel.) You're looking for leaks in the feeder cables.
    Unfortunately I don't have one, just a voltmete.

    I've talked to my electrician about coming to take a look. He said he would have to test a few things. Problem is, he is so busy all the time + he's a friend of mine, so he knows I won't get (too) mad at him LOL.....

    I have good friends who are: 1)HVAC (actually 3), 2) Plumber, 3) Electrician, 4)Land clearing, 5) Roofer, 6) Auto mechanic. You would think I'd have it made.

    They always treat me really good and do very good work, but getting them to come out sometimes is like pulling teeth!!! But its nice to have someone who will talk to me I guess. I always pay them more than they ask, but that's the way it goes.
    Last edited by Robert Engel; 09-12-2018 at 2:39 PM.

  15. #15
    Is the 40A sub-panel breaker located in your main house panel or somewhere else?

    Was there anything out of the ordinary preceding the 40A breaker tripping? Electrical storm, high winds, heavy rains...?

    When you reset the 40A breaker, was it a solid click or did it feel a little sloppy or weak?

    You can do some tests with your voltmeter that would help. Test the voltage before the 40A breaker. If it's in the house panel, remove the cover and put the test leads across the main lugs. Then check the voltage on the load side of the breaker (the lugs on the breaker). Then test the voltage where it enters the shop. If you see any unusual voltage drop, more than a couple of volts or so, you may have a bad breaker (if the drop is at the lugs of the breaker) or bad connection somewhere or open insulation underground that's bleeding to ground.

    It could very well be there was a spike and that breaker picked it up. I once had a 2000A, 480V disconnect fail to trip and it went through every current protection device upstream until it finally tripped a 112kV transformer and shut the whole site down. There were some very angry people that day.

    Anyway, if you can't find anything unusual, you'll have to wait and see if it happens again. It may not.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

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