# EMP-like Effects from Lightning



## NoClue (Jan 22, 2007)

For most of my career Iâve worked in communications â satellite, microwave, terrestrial broadcast, etc. and over the years suffered equipment failures from a wide variety of sources such as back-hoes, hurricanes, burrowing owls, nesting birds, stray rifle rounds, and most prominently, lightning. A direct lightning strike is devastating and the damage it causes is generally obvious. Less obvious, and far more difficult to correct, is the damage caused by close proximity lightning strikes.

The general precautions taken against lightning strikes are generally well known and include adequate grounding, lightning rods, lightning dissipation devices, lightning arrestors, fuses, breakers, and so on. The facility at which Iâm currently employed - a satellite uplink site - has all of these in abundance and more, yet we recently experienced a strike (we donât know exactly where â we know more about where it wasnât than where it was, and it was to the building or the antenna farm) and yet we experienced multiple equipment failures in a wide variety of systems. In the process of restoring the effected systems, Iâve discovered a few things that may be of interest or use to the Preparedness Community, so I thought Iâd share.

First and foremost to be considered is that we did not experience a direct strike. There are no smoldering trees, no craters or any other direct evidence of a strike. We have layers of power redundancy, power conditioning, back up power, and surge suppression. Not a single fuse, arrestor was blown, and not a single breaker was tripped with two exceptions. There are no indications in our power logs of any transients in our power distribution, nor with a couple of exceptions (discussed below), are they failures of the nature one sees as the result of a power surge. All of the evidence points to an inductive discharge type event, very similar to what would be experienced in the event of an EMP.

Similarities between EMP and lightning related damage have been noted in the past but have not been heavily studied. The IEEE has a few papers on the subject, as does the FAA, but there is a general lack of hard data or research on the subject. As with EMP, the effects from lightning are largely dependant on the distance from the strike, and/or the distance from discharging conductors. One can quibble as to whether or not lightning related phenomena constitute an actual EMP, but the effects are real, far more likely to be encountered in everyday life, and similar enough that the lessons from one can be applied to the other.

In diagnosing and repairing the damage, Iâve noted several common threads in the types of systems damaged, and going down to component level, what was damaged. The most obvious shared trait is that all of the affected systems were connected to outside components. My facility is heavily automated (Iâm the only full-time employee here), and relies heavily on sensors and monitoring equipment as well as serial (RS232, RS422, and RS485) comms. Almost every one of these sensors and com busses failed all the way back to the host device.

Fortunately, the resulting damage was not as extensive as expected from a nuclear induced EMP event. Equipment failures were generally confined to the comm. sections of the equipment and the exterior sensors. In a few cases, where multiple sensors shared a com port or interface, an interior sensor was affected as well. The power related systems failures were confined to perimeter security systems which, by design, are semi-autonomous. In these systems there were power supply failures (AC to DC, or DC to DC conversion) wherein 1 or 2 diodes in a bridge rectifier, and in a couple cases, linear voltage regulators were damaged.

My facility is remote and is designed to be self-sufficient. Because of this, we had most of the parts needed to effect repairs. Because we have layers of redundancy, we never lost our main links and service was never significantly impaired. The main lessons learned were 

1.	Keep plenty of spare parts, and spare parts for your spare parts.
2.	Know your critical systems, what external systems they rely on, and which sub-systems are most likely to fail.
3.	Have manual backups for anything normally automated, even seemingly trivial things.
4.	Stay calm, pace yourself, and donât underestimate the restorative power of a short nap.
5.	Anything outside your building and anything itâs connected to on the inside, no matter how well youâre shielded or grounded is still vulnerable.

I realize that few of you rely on serial communications for the maintenance and well being of your homesteads, but I hope that my experiences at least give you some insight or some inspiration on how to improve your own situations. I've had experiences where a computer near a window was blitzed when a tree in the yard was struck, so it can happen at home too.


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## damoc (Jul 14, 2007)

thanks probably the best imfo i have read on possible emp effect.

from what you have seen do you believe that solar panels would be destroyed
totally?


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## Harry Chickpea (Dec 19, 2008)

The issues with RS-232 and ground loops and lightning are well known. (For those who don't know the jargon, RS-232 is the serial port on the back of older computers, where we used to plug in those modems. The ports are still used for data-acquisition, cash drawer and pole display connections, a type of slow networking, and other legacy serial connections. The higher speed USB serial ports have made them somewhat outmoded.

Robust RS-232 systems have either opto-isolators (where there is no electrical connection from one end to the other), or surge and lightning protection. A primary problem issue is that data cables going over any extended distance usually do not go to a single ground point. RS-232 cable can go for a mile in some situations, between building with totally independent ground rods.

A key point is that if there is an electrical charge that affects all parts of a component equally, it does little damage. Put a plus 100,000 volt charge on one lead of a resistor and have the other lead at plus 100,005 volts and little will happen. Put as little as a 200 volt charge on one side of some resistors and a zero voltage on the other, and they will fry or be subtly damaged and unexpectedly fail within six months.

Having a single ground point and COMPLETE ISOLATION from other possible grounds prevents the differences in voltage caused by natural ground resistance from increasing the voltage potential on one section of the system to a level above that of another point.

What is totally under-reported by the media is the existence of false leaders around a lightning strike, as well as the possibility of no-bolt discharges.

When the ground is charged one way, and the clouds above the other way, and the difference is enough to start to break down the rain and air, people usually see the bright jagged bolt of lightning. It is jagged because that path, even though it wasn't straight, happened to have the least resistance to the electricity. On the ground, the area under the bolt will have multiple oppositely charged tendrils of weak lighting that work upwards, attempting to connect with the main bolt. One or sometimes two will succeed, and the others subside -usually without being visible. The effect is most extreme in the immediate area of a cloud to ground strike, but can occur almost anywhere.

You do NOT have to be struck directly by a bolt of lightning to be killed. One telling photograph I have seen is of a herd of about fifty cattle that were standing in a more or less line about 150 yards long near a barbed wire fence when it was struck by lightning. All of them died. The ground currents and the false leaders did the job.

No-bolt discharges, as I mentioned, are also under-reported. Once you are aware of their existence, you can often recognize them. During the last storm here, we had a nearby strike, and I had noticed the fairly regular cadence of the strikes getting closer. At about the time when I would have expected the next strike, I instead heard a distinct sizzle outside, as if I was standing near an overloaded high voltage line in the rain, but heard and saw no strike. The same thing happened one more time and then the storm moved on. In those cases, there were likely multiple paths of low resistance between relatively close charged areas, and while the energy was enough to have electrical effects, it wasn't large enough to create a bolt.

Any military EMP pulse, especially in a rural area, would likely have far less of an effect than nearby lightning. Unless you live near a major power plant or military complex, there would be no reason to waste munitions destroying non-critical targets.


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## NoClue (Jan 22, 2007)

damoc said:


> thanks probably the best imfo i have read on possible emp effect.
> 
> from what you have seen do you believe that solar panels would be destroyed
> totally?


Not the solar panels themselves, but quite possibly the line charging, regulating, and inverting equipment they connect to.


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## WanderingOak (Jul 12, 2004)

Regarding the original post, for some reason, I read 'back-hoes' as 'black holes', and thought to myself that this was going to be an interesting post.



NoClue said:


> Not the solar panels themselves, but quite possibly the line charging, regulating, and inverting equipment they connect to.


Is it possible to build a Faraday cage around the control equipment, or would the power lines from the panels still allow them to be fried?


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## AngieM2 (May 10, 2002)

Thank you for this EMP/Lightening lesson.

I think this forum would be a good place for more informative pieces such as this.

I'm going to have to read it 'in depth' when I have more than just a few minutes here.

Thank you - Angie


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## NoClue (Jan 22, 2007)

WanderingOak said:


> Is it possible to build a Faraday cage around the control equipment, or would the power lines from the panels still allow them to be fried?


I think some kind of arrestor or fusible link/fuses would reduce the likelihood of frying them. 

My experience also says that once the first step in the path is destroyed, the damage stops. Whatever the first stage is - the charge controller, I'd assume, but I'm no expert (yet) - I'd have a spare wrapped in ESD packaging stashed somewhere safe.


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## NoClue (Jan 22, 2007)

To Harry Chickpea:

Thanks, that's good info.

Now that the damage is pretty much repaired, our next step is future prevention. The company's immediate suggestion is RS-232 lightning arrestors, but I'm pushing for full optical isolation. We have an extensive grounding system, but I suspect that it's damaged or segmented by corrosion somewhere. I'll be investigating that with a passion over the next few weeks.


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## wyld thang (Nov 16, 2005)

I dont' know if this is in the same category, but whenever there is lightning or a powerful storm that will knock out power, I unplug the important stuff. Some thing to do with the power surge, or balls of fire that can fry an appliance...anyways, surge protecters or turning it off aren't enough, you have to UNPLUG. And keep it unplugged until the power is back on normal. WHen they turn the power back on that can be bad too. somehow...I dont' know how it works, or if that's right, but my computers still work


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## AngieM2 (May 10, 2002)

I also unplug and uncable the tv's, computer, and the computerized sewing machines.

I grew up with the tube radio stuff and then the transistored radio stuff, and Dad always was disconnecting and throwing the main switch to all of it when lots of lightening was around.


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## wyld thang (Nov 16, 2005)

Every winter here they actually talk about this on the news, power surges and lightning "coming through the wires" to blow things up. THey always say to unplug, that even if the breakers are off (which is good too), the charge can still travel through the connected stuff--thus you have to create a physical break or gap in the lineup which is what NoClue was kinda talking about(I think?).

They interview people who saw balls of lightning shoot out of their outlets--have to admit, that's kinda cool, kinda

PS I like our news here, it's actually pretty informative, educational about prepping for disasters, without being junior high about it.


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## Harry Chickpea (Dec 19, 2008)

There is nothing wrong with unplugging items. However...
If you unplug a tv, you need to disconnect the cable or antenna.
If you unplug phones, you need to unplug both the phone jack and wall wart.
If you unplug your computer, you need to disconnect the cable to the cable modem, or phone line to the dial-up.

Personally - from my background from the time I was in my crib many years ago (my dad had his ham shack in my room) - I prefer a good ground at the electrical entrance, with all other utilities tied in there, a whole house surge protector, or failing the whole house unit, Isotel or Isobar surge protectors from Tripplite. I had a commercial customer that had a direct lightning strike wipe out their main entrance panel and all circuit breakers to a major building. The computer system that I had installed and protected with the Isobar units was completely safe and fine. One of the Isobars did get fried, but that was all the damage that occurred to my hardware.


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## fordy (Sep 13, 2003)

.............I'm thinking the EMP had 3 possible points of entry , tower mounted antenna(s) , the tower itself , and the A\c power lines entering the building . If , it came in over the AC power lines , it should have been routed to ground at the transformer or so I've been told . If it entered over the antennas then maybe the grounding is better for the inside equipment than the tower ground systems . I would have thought that the EMP would have hit the tower which should have had the most direct path to ground , but maybe I'm not understanding the setup where you are working . , fordy:cowboy:


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## AngieM2 (May 10, 2002)

"


> I was in my crib many years ago (my dad had his ham shack in my room)


My crib was in the ham room.... 

Same difference.... I know what you're talking about.


And I do the cables and the power cords when I disconnect.


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## Jim-mi (May 15, 2002)

I have two old UniSolar 880 panels that I suspect were fried by a "nearby".
Years ago I had a Trace SW2512 inverter fried by a "nearby" . .??? How close was it . . I'll never know.

When the lightening gets uncomfortable, the first thing I unplug the phone line . . . .Yes I've lost phones from not even close strikes. Then opening circuit breakers . . . hope the surge doesn't jump the gaps in the breakers.

Good info on this thread.
Hope lots of folks take heed...........


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## NoClue (Jan 22, 2007)

fordy said:


> .............I'm thinking the EMP had 3 possible points of entry , tower mounted antenna(s) , the tower itself , and the A\c power lines entering the building . If , it came in over the AC power lines , it should have been routed to ground at the transformer or so I've been told . If it entered over the antennas then maybe the grounding is better for the inside equipment than the tower ground systems . I would have thought that the EMP would have hit the tower which should have had the most direct path to ground , but maybe I'm not understanding the setup where you are working . , fordy:cowboy:


My hunch is that it came from the area of the fence line on the south east corner (based on what was effected and what wasn't). The active part of the facility is 4 1/2 acres. Our uplink dishes are 13 1/2 meters, but were not directly affected. We have an extensive underground ground plane, covering maybe 2 of the 4 1/2 acres, with numerous tie ins, and our dishes are heavily grounded.


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## Harry Chickpea (Dec 19, 2008)

"What about whole house surge protectors? Do they work and are they worth the money?"

In a word, yes. Of course it depends somewhat on the area, and the level of power problems you experience, but more and more items need surge protection. In the thread about stoves failing more that in the past, I commented that most stoves now have computerized systems in them rather than the old basic electromechanical systems that were more robust. If such an installation can double the useful life of a single appliance, like a stove or television, then it has already more than paid for itself.


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## soulsurvivor (Jul 4, 2004)

rose2005 said:


> We have surge protectors on our computers, but I never thought about other stuff. I have now bought a whole house surge protector for DH to install. Appreciate the advice.
> 
> Rose


Rose, thanks for asking this question. It's not something I had considered in our house remodel, but with new appliances going in, it's the perfect time to have this protector installed. I'll likely turn it over to our contractor that's doing some of the other electrical work here, but what type/brand of surge protector did you purchase?


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## Freeholder (Jun 19, 2004)

It's not EMP, but it was an indirect hit from lightning -- when I was small and we were still living on the homestead in Alaska, one day when I was (reluctantly) washing the dishes during a thunderstorm, I suddenly felt like someone had hit me hard on the right elbow. I jumped and yelled "Who hit me!?!" (I had two younger brothers running around the room). Lightning had hit nearby, and the electricity traveled through the groundwater and through our pipes into the dishwater, and out my elbow. Just one more thing to consider when it comes to lightning.

Kathleen


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