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On taking a lightning strike and the EMP(Electro Magnetic Pulse)

with 14 comments

Or, don’t mess with Mother Nature

About  a decade ago at home, during a thunderstorm, I was using a computer with a CRT monitor.  All of sudden there was a huge loud cracking sound.  In an instant, my CRT monitor was a rainbow of colors. 

Long ago, having experimented with a magnet and a television set, I know that placing a magnet close to a television (CRT) and turning the magnet can produce this same rainbow of colors. 

Some CRTs had a degaussing feature that would remove any significant magnetism from a CRT.  There used to be degaussing loops used to accomplish the same for televisions.  These are also used to erase magnetic tapes.

During that crack of lightning, in addition to creating a rainbow of colors on my computer CRT monitor, I found that a VCR was fried as was my C Crane radio.  The computer continued to work as normal even though it was on during the event.

After this event, not wanting to mess with Mother Nature, I purchased surge protectors, and a UPS for some of my equipment.

However, this was not enough to protect my equipment from a second attempt by Mother Nature to destroy my electronic equipment

Taking the lightning Strike

Last Thursday, late at night, I heard anther very loud crack of lightning.  On Friday morning I tuned on my computer to find out that I no longer had a network connection.  All my networking gear in the basement.  Checking out the basement, in the corner where there is usually lots of blinking lights, there was darkness.

The strike took out the UPS.  Taking the UPS out of line, my DSL modem came back, as well as my wireless router.  The server in the basement which is my home network file server would boot but would not come back on-line.  The light by the RJ-45 network jack was dark.  Checking the computer control panel devices tab – no network card was in the computer – according to windows.

Further investigation showed that the lightning strike took out:

  1. The network card in my computer
  2. A Comcast cable set-top box
  3. One digital television set
  4. An Astron 35 amp power supply that was tuned on
  5. An iPod dock with an iPod Touch charging

Things that didn’t care

  1. A cheap clock radio
  2. Other digital television sets
  3. Everything else

Power Surge or EMP (Electro Magnet Pulse)?

It did not seem to matter that I had all this equipment on surge protectors.  The Astron power supply was on a heavy-duty Isobar surge protector – supposedly a high level of protection – yet that power supply now shows 3 volts down from 12 volts.  The Ultra UPS was taken out completely including the network card in the computer that was attached to it.  The television that was damaged was on a surge protector.

Here is the thought.  I could be wrong – but my experience a decade ago with that lightning strike that produced a rainbow of colors on my computer CRT monitor – and the computer kept running –  suggests to me that these strikes produce a huge EMP that no surge protector can save you from.  In fact, if these huge EMP’s are produced by lightning – so much magnetic energy that it can turn a CRT into a rainbow of colors – what protection could you possibly have?

How can you protect yourself from a EMP?

The other challenge is that many electronic devices are never “off”.  A television, DVD player, Home Theater System, and other devices are always self-conscious waiting for you to push the “on” button on the remote.  They are already “on” listening but not “on” as a fully capably device.

If a lightning strike can produce a huge magnetic field, any wire inside the device can have a current flowing through it.  Delicate electronics can be easily damaged.

For devices, such as television sets that are hooked up to cable, a lightening strike could very easily induce a current in the cable and blow out the front end of the television.  Same for a radio with an external antenna.  I wonder if these devices – it would make sense – if they had some sort of physical relay between the antenna input and the receiver front end that engages only with the power is on.  In this way induced EMF caused by lightning could not get into the device if it was tuned off.

So, based on my experience, I am getting the idea that a nearby lightening string that can create a magnetic field strong enough to turn a CRT into a rainbow of colors is going to be able to induce currents inside electronic devices for which there is no protection.  These are not “line surges” that a surge protector can save you from but huge magnetic fields that can induce fields and currents inside devices and along wires such as network cables, satellite &  TV cables, and antennas of all sorts.  The fact that some of these devices are never “off” exacerbates the problem.

Life is ruled by Ramdomness

Like the residents of Pompei enjoying the beautiful view of Vesuvius or the Dinosaur watching that flaming rock come from the sky at 26,000 miles per hour, sometimes you are just in the wrong place at the wrong time and there is nothing you can do about it.

Written by frrl

May 9, 2010 at 5:28 am

14 Responses

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  1. The most tragic thing about all this lightning talk is that only one person out of ten knows how to spell lightning. It’s NOT lightening. Lightening is when somebody takes a partial load off of something, which would be making it LIGHTER, hence lightening..!!!


    August 25, 2015 at 8:43 pm

  2. Yesterday 8/8/14 a lightning bolt hit a house about 4 to 5 hundred from my house setting it on fire. At the time it happened i was on my computer and I heard a loud crack out of my computer. The next day I turned on another PC with 2 CRT monitors attached that had been in sleep mode during the lightning occurred and both of them had totally wrong colors on the screen. I had to go into setup mode and use the degaussing feature and then they were fine. I think that there was an EMP from the strike that hit the monitors and the speaker system of my PC.


    August 9, 2014 at 12:11 am

  3. Well i have been a after sale regional manager taking care of all repair issue and we have to repair more then 10 000 faulty rectifier every year, and finally i had found a product and understand what and how prevent EMP.

    As of today there is little knowledge regarding EMP and this why there is no protecting device design to protect equipment from them, but from now on there is such protecting device and you have full protection.

    Check out this in youtube pat5-c3-16-250 or for more detail.

    Mike Soh

    May 5, 2013 at 7:09 am

  4. I guess I am the latest member of the Got Screwed By Lightening Induced EMP Club. On Wed, April 10, 2013, at about 7:45 am, There was loud lightening and thunder directly over our 18 unit building. Two residents had their TV’s killed. The elevator got stuck in the open position. The door-buzzer got stuck on “buzz open” [fire department came with five trucks], and the Ethernet ports on my At&T modem, and my Dell Tower were fried. At&T gave me a new modem, and sold me a USB wireless router thing, so my old Dell could talk to the modem without an ethernet card.
    I was watching a tube TV at the time, and it was fine, the TV’s that died were on the other side of the building, on opposing sides of a courtyard.
    I wonder if they make shielded ethernet cable?

    Reese T.

    April 16, 2013 at 10:53 pm

  5. I had too suffered from lightening strike due to EMP. Lightening struck a tree about 15 feet from my house. Lost a VCR, a cable modem, a router, a VOIP telephone box, and the AM portion of a desktop radio (FM still works fine), All of this stuff was attached to something (cable/AC), but I also had a portable radio sitting on the dining room table (I had just finished using it). The portable radio was attached to nothing, but after the strike,it was permanently dead.


    July 8, 2012 at 4:30 am

    • We had a lightning strike to a pine tree about 20 feet from our electric meter and cable boxes. We lost a controller board in the A/C compressor, cable modem and wirless router, a clock radio, lost high-speed setting on a remote controlled ceiling fan. our wireless telephone base was knocked out, the hand units will still work in the intercom code, the ethernet card in one computer was fried. I don’t know what else we will find but the sad part is the “Whole House Premium Surge Protection” provided by Gulf Power didn’t do anything to stop all this damage. In fact, the technician from Gulf Power came and checked the surge protector and said there had been no surge on the power line. This seems strange that lightining could strike within feet of the cables coming into my house and not induce a surge into the cables. Anyway I’m on the hook for repair costs unless I decide to fight the home owners ins, company. It may not be worth it with my rather high deductible..

      Lloyd Stanley

      July 19, 2012 at 9:21 pm

  6. While Lightening induced EMP could potentially be the culprit (or at least have contributed to the electronics failures), there is another component to consider. A lightening strike to any conductive line, not just power lines, (or a strike near any conductive line) can induce a surge in that line. Coaxial cables carrying cable TV and/or cable internet access, phone/DSL lines, etc., are all vulnerable. Even if you have lightening arresters installed in your power lines, surges can still couple to phone/DSL/cable lines and damage connected equipment. Also, note that even the most top of the line surge protectors are not designed to guarantee protection against surges from lightening strikes. While surge protector might be able to handle a relatively weak surge induced by a distant lightning strike, protection from nearby lightning induced surges requires specially designed lightening arresters. No solid state electronic equipment (surge protectors use solid state electronics) can withstand a surge as powerful as that from lightening, even a surge that is induced in the line indirectly from a strike nearby the line but not directly hitting it. High grade lightening arresters use a specially designed spark, glow discharge tube, or similar technology to handle very powerful surges. However, for most home networks, the cost of lightening arrester is not worth it, as the odds of a strike close enough to require a lightning arrester over a regular surge protector are fairly small. Usually only data centers or similar facilities with very expensive equipment with a high reliability requirement and/or high demand use lightening arresters. However, even a low power surge that a regular surge protector can stop can still fry electronics if the surge is in a cable/phone/DSL line as opposed to a power line. They do make surge protectors now that have, in addition to power outlets, ports for coaxial cable to connect to (one for input, the other for output). These dual line surge protectors will stop surges in the coaxial cable line as well as the power line (subject to the same limitations regarding very high power surges from nearby lightning strikes) before the surges reaches electronic equipment and damages it. I do not know if they also make surge protectors for phone/DSL lines (I’ve only every seen the coaxial cable ones), but it stands to reason that they probably make those too.


    May 17, 2012 at 2:49 pm

    • For coaxial cable most of the EMP will be on the ground line. The real culprit, as indicated by the damage, is the copper phone line that DSL connects to. Fiber avoids this. I’m guessing Verizon made our neighborhood one of the first to get FIOS because our power lines are underground (no overhead ground wires to catch the lightening). Before FIOS, when our house was struck by lightening, our neighbors phone blew completely off the wall. I’m sure it took a toll on the Verizon equipment as well. The copper phone like and DSL was probably a direct lightening hit rather than EMP.

      Perry Webb

      April 4, 2015 at 6:24 pm

  7. I too was a at the business end of an EMP as lightning struck some distance behind our house and left a television screen extremely dim with only reds and greens displaying. My CRT monitor wich was disconnected from the mains also displayed the same behavior for a short time though the TV did not change. Stuff happens I guess.


    December 15, 2011 at 10:04 am

  8. […] space. If the satellites can survive, a lot of other stuff will too. Google is your friend… On taking a lightning strike and the EMP(Electro Magnetic*Pulse) […]

  9. Lightning-induced EMP is very much the culprit in these losses. I had had it happen to a minor degree on several occasions in the past when nearby lightning strikes blew the ethernet ports in two of my computers. I put surge protectors on them thinking this would solve the problem once and for all. In addition, most of my electronics and all of the computers are on surge-protection battery backup systems, and the house is “protected” at the electrical service entry point by a whole-house surge protector.

    However, recently we were awakened by an early morning thunderstorm that came right over the house. I knew we were in deep kimshaw when I saw the flash and heard the thunder at the same time. Sure enough, lightning had hit a large tree directly behind the house. The good news was that it hit the tree and not the house. The bad news is that I have been spending the past month replacing most of the electronics in the house.

    Verizon had to replace ALL of its FiOS equipment in the house including the ONT, router, and three HD DVRs. Luckily the insurance company will not have to pay for that as the equipment is rented from Verizon.

    But in addition the strike damaged the USB ports and the ethernet port on my Mac Pro despite the presence of a Tripp Lite surge protector specifically designed to protect the ethernet port from this sort of event. I also lost two TVs, two DVD players, my Yamaha AV receiver (now turns itself off one second after it’s turned on–output load protection circuit must be damaged), the home’s security system (no longer manufactured and must be replaced in its entirety) the HDMI inputs on the home theater projector, an ethernet hub, two USB 7-port hubs, a TV tuner and a flatbed scanner for the Mac, the Wii console, one of the exterior security cameras (the one nearest the lightning strike), several X-10 lamp control modules, and the entire whole-house infrared remote control repeater system–every target in every room was zapped. Not to mention that the tree it hit was split wide open and will probably have to come down.

    The sad part is that, short of wrapping a huge faraday box around the entire house, there is nothing that could have prevented this. And, if another lightning strike occurs near the house tomorrow I will probably be going through this process all over again.


    September 25, 2010 at 12:59 pm

  10. I owned a computer store/computer service company in central Oregon. We got a call from the big radio station in town… they were off the air after having a lightning strike near the building. Upon arrival, I expected to find blown power supplies, but all of them were intact. The radio station setup was that the CPUs were in one room, and the keyboard/mouse/monitor were in another room. The wires ran right next to the wall that was nearest the lightning strike. That’s when I found out that lightning produces a tremendous EMP… the keyboard BIOS chips were all blown. UPSs were installed, but they could not prevent the pulse from travelling down the kb, mouse and video cables and directly onto the motherboard. No real solution except maybe put the cables closer to the interior of the building. As was previously noted, sometimes shjt is just going to happen!


    August 7, 2010 at 3:19 am

  11. We just experienced an EMP at home – took out D-Link modem/router and an HP all-in-one printer. Not sure about anything else yet. Router was in a backup battery’s surge protector (computer on that backup battery seems okay – not sure about network card yet). Modem/Router also seems to be trying to work. Printer won’t power up even though the power supply seems to be working – it was plugged into a fused surge protector. Both were near a window.

    Plasma TV, old CD/DVD player, small analog TV all seem okay. Not sure about VHS/DVR yet – I think it’s probably fried too – it was in backup battery with Plasma TV.

    Verification of EMP? Family across street from us lost their router as well and it wasn’t attached to anything.

    I’m sorta scared to turn on the 2 laptops.

    Deb Haas

    June 29, 2010 at 9:07 pm

  12. I also observed a monitor create a ‘disturbance’ when a mobile phone handset is placed close to it. In fact you can assume that a call is landing even before you hear / see it on the handset.

    To what do we attribute this action?

    Anil Atluri

    May 9, 2010 at 9:25 am

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