Wednesday, February 03, 2010

How To Protect Your Electronics From An EMP Attack

From the Preparedness Pro:

Faraday Cages
By Kellene Bishop

Faraday Cage c/o

Faraday Cage c/o

We’ve established that an EMP incident will fry all electronics. This occurs whether or not they are plugged in or turned on. This also affects automobiles, batteries, computers, medical equipment, etc. Needless to say, in such an instance, life as we know it will change dramatically. Even more distressing is the fact that the strike of an EMP is not likely to give any warning. You don’t see it. You don’t feel it. You are simply left with the sudden consequences and whatever preparedness you have on hand. So, other than your preparedness supplies, your new best friend may be a Faraday cage. In fact, with the knowledge of the protection that a Faraday cage can provide you, you may be able to enjoy nearly as comfortable a lifestyle as you did prior to any electromagnetic pulse.

While being mentally prepared to live in the Stone Age may be helpful, it’s not necessary. Aren’t you glad?

First of all, allow me to dispel some myths about Faraday cages—and boy, howdy, there are a LOT of them.

  • Whether or not your electronics are plugged in, how long of an antenna you’ve got on something, what voltage it is, or whether or not they operate with batteries—all non-protected electronics will be affected by an EMP.
  • Batteries will be affected, usually in the form of “shorting” as well.
  • Electronic phone systems will also be damaged.
  • Surge protectors are useless in the event of an EMP exposure.
  • Just because your car has rubber tires, it will not be impervious to the effects of an EMP. Rubber containers are insufficient protection against an EMP.
  • And oh yeah—yes, your Faraday cages DO need to be grounded. If it’s NOT grounded, then the Faraday cage merely becomes a reflector or an amplifier.
  • Yes, a microwave can act as a Faraday cage, but why in the world would you want to use it for that? That’s just silly when you can make one simply.
  • Faraday cages do not have to be solid, thus the name “cage” instead of the oft misused term—“box.” In fact, many of them that you can build yourself or will see on the internet will resemble a bird cage or a very finely meshed chicken coop wire.
    Copper Mesh photo c/o

    Copper Mesh photo c/o

  • Also, contrary to what you may see on the internet, a sheet of foil on a box will not protect you. It’s not thick enough to withstand the pulse. However, you CAN protect your items if they are buried a couple of feet underground in every direction (up and sideways.)
  • Last, but not least, a car is NOT a Faraday cage sufficient to withstand an EMP incident. It has some similar components, yes. Most cars made today consist of fiberglass and disjointed parts, not a continuous metal material. In addition to that, they are on tires. Tires on a car do NOT serve as grounding. Folks are simply getting an EMP strike confused with a lightening strike. Now, IF you had an old fashioned car that was made of metal, that had its tires removed, that was also attached to an Iron or copper pole and that was ALSO on dirt—not gravel—then yes, you may have a car that doubles as a Faraday cage. (Kind of like the old clunker my dad has out in his “back forty.”
  • The cages do not have to be solid, but they do have to be constructed continuously without gaps between the protective material.

There. Now that we’ve discredited 90% of the internet information out there, let’s continue.

Michael Farady photo c/o

Michael Farady oil, by Thomas Phillips. photo c/o

Faraday cages are named after Michael Faraday who invented them in 1836. They block out external electrostatic fields and electromagnetic radiation. One mistake many people make when it comes to an EMP is to compare it to a lighting bolt. The effects of an EMP and a direct lightening bolt are very similar, but they are not at all similar in terms of their visibility, and affect on the body. An EMP is more like a radio wave, not a visible bolt of light or electric current.

It’s the substrate layers of the diodes and transistors that make them susceptible to a magnetic pulse attack. Electronics are made up of diodes and transistors and substrate layers. A computer, car, television, and cell phones are made up of tons of transistors. When hit with a powerful magnetic pulse, the substrate layers are destroyed. However, early 1960’s and before electronics did not use substrate layers. They used vacuum tubes. This is why older electronics are less susceptible to damage. This is why a human or animal body will not be affected. Yes, our bodies consist of an electric volt. But understand there’s a difference between electricity and electronics.

I just want to reiterate this again. It’s important that any Faraday cage that you plan to use is grounded. It has to be grounded in order to disperse the energy.

What you should know though is that a Faraday cage is not fool proof. The higher the frequency of the magnetic pulse, the faster it is. This is what causes the burn out. The cages must be grounded, continuously connecting, and the openings of them cannot be too large. Chicken coop wire would work, but only if you double or even triple layered it as the opening are too large. For a reference of opening size, look at the front of your microwave door. It’s a small mesh. Just a like a snake can slither its way through the right sized hole, so can an electronic wave.

Galvanized Trash Can photo c/o

Galvanized Trash Can photo c/o

You can have an instant Faraday cage with a galvanized trash can or a large stock pot like they use in restaurants. (Be sure to clamp the lid down. Remember—continuous connection is key. Since Faraday cages are not fool proof, depending on the strength of the pulse, I would recommend burying such containers 2 feet under the ground, storing survival electrical and battery items. (Including batteries).

An easy way to make a Faraday cage would be to acquire some 2 x 4 brass mesh sheets. (Mythbusters on the Discovery Channel did a couple of experiments using this successfully.) Make a box frame with the 2 x 4’s and staple the brass mesh to the outside. Create a securely attached/connected access entry within the frame. Solder a ground wire to one of the corners and ground the cage. Scrap metal and mesh wires can easily be obtained in junk yards, on E-bay, the clay modeling section of a craft store, or at your local hardware or “farm and feed” store. The important aspect of this to remember though is that mesh or sheet metal only shields magnetic fields if the frequency is up in the RF range. To properly stop the wave, you need some iron, steel, or some slabs of thick copper. Most electronics are useful in the VHF/UHF/SHF range today and will need more substantial protection. Remember when you’re browsing the internet. Protecting against sparks is not the same as protecting against a strong magnetic pulse.

You can make your “cage” as small or as large as you’d like. It wouldn’t be out of the question to continuously line a basement storage room or hole in the ground with copper mesh wire and a grounding rod.

Bottom line, with an appropriately constructed Faraday cage, you can likely protect that which is inside from the electromagnetic attack of an EMP incident or solar flare, thus preserving the function of all that is contained therein. Here is a very simple example of how Faraday cages work. (DO NOT try this at home, please)

Note that the Peeps are put into a mesh bowl and covered with a mesh cover. They are then put in the microwave. The one Peep that wasn’t put in the microwave met his untimely death, while the others were still intact.

For a little bit of a science lesson on the workings of a Faraday cage, check out this YouTube link. The science professor is EXCELLENT. Note though that he does say that a car is a Faraday cage, however, I want to reiterate that it is NOT sufficient to extinguish the effects of an EMP attack.

Photo c/o

Photo c/o

Be selective in what you protect. It makes no sense to protect a cell phone, for example, as the cell towers will be useless. If it were me, I would protect radios, communication devices (such as a HAM radio), batteries and all of their respective tools, thumb drives loaded with all of my vital information, and a laptop. Keep in mind that a Faraday cage should be your LAST concern in terms of protecting every electronic that you enjoy presently. It’s not like if you preserve your television you’re going to have any “juice” to plug it into. Don’t focus on a Faraday cage and its time, effort, and expense at the risk of neglecting food, water, and medical supplies. It would be better for you to read up on solar power, wind and steam energy instead.

* EMP 101: Part I–The Likelihood.
* EMP 101: Part II–The Aftermath.
* EMP 101: Part III–Prepare Medically.
* EMP 101: Part IV–Faraday Cages.

Copyright 2009 Preparedness Pro & Kellene Bishop. All rights reserved. You are welcome to repost this information so long as it is credited to Preparedness Pro & Kellene Bishop.
Wiki confirms this information. I know, I know, you can't trust Wiki. But usually, USUALLY, you can trust WIKI on science stuff.

There now, don't ever tell me Infidel Bloggers Alliance doesn't try to help. At IBA, we care.



Anonymous said...

1. In the first paragraphs, it stresses that the cage must be grounded appropriately to succeed. In both experiments, nothing is shown to be grounded (or I simply don't understand) . . .can someone kindly explain this in easy to comprehend terms?

2. About basement rooms, well below ground (9+feet) where/how does one ground the cage?

3. Despite best efforts to ground and wrap continuous vendi cages around basic equipment (utility box, furnace, water heater, telephone lines etc.) this will only save the caged equipment not the lines bringing power/communication services? All the lines bringing power and communication lines to individual homes do not typically lie two feet underground - especially at juncture with house. Right?

Pastorius said...

I think I know the answer to your third question;

you can only save your cell phones, batteries, and radios this way. Stuff that can work independtly of deliverable electricity.

One has to wonder if hospitals, radio stations, and television stations have a contingency plan for EMP. Sure, they have generators, but the generators will not be able to feed electricity through fried wires.

Maybe there is no hope, if this happens.

midnight rider said...

Hate to be johnny raincloud but it won't matter if you save your cellphones and radios if their towers are shot to shit from the emp (and they will be).

Pastorius said...

Like I said, maybe there is no hope.

One would think cell companies had thought this through.

I know the military has.

Have hospitals? If not, then why not?

midnight rider said...

The military has thought it through, at least parts of the military, but I would doubt very much the civilian sector knows about it. The military doesn't talk about it often (not that I've seen) nor does the MSM.

There is no way America -- nor most any other nation -- is prepared for this.

Anonymous said...

Read "One Second After" by William R. Forstchen for an EMP scenario that will chill you to the bone. What happens to people when they are hungry, thirsty, diseased and desperate? Chaos, violence and dog-eat-dog behavior diminishes the most civilized among us in a remarkably short period of time.
All of the preparation in the world does no good when the EMP strikes and you are 55 miles from home, in a strange town, perhaps off an unfamiliar freeway exit or in an airplane. Wherever your car is when the strike hits, that is where you will be for awhile. Hopefully there's a jacket and some walking shoes in the trunk of your car and you have a good sense of direction. Grab that half-eaten granola bar and the bottle of water that you tossed in the back seat. Pray that it's not yet dark.
This is real folks.
NorCal Rosi

revereridesagain said...

"OSA", besides being a good read especially for us disaster junkies, does a pretty thorough job of describing conditions in a semi-rural college town following an EMP. Good for waking up anyone but the sort of idiot who still thinks EMP is "science fiction". Unfortunately, that's a lot of idiots.

Epaminondas said...

IMHO - The primary function of saved electronics will be it's INTRINSIC BARTER VALUE, except for a very few items a laser ranger for a high velocity weapon.

So protect stuff like ipods, and go and order the actiontec or action prep crank chargers for items like this from LL Bean and Eddie Bauer. Protect crank power radios and lights. As for your laptops, unless you have self contained information/applications which will be of help in a 15th century OR LESS society, they will be worth as much as a brain surgeon who specializes in micro-aneurysms .. EXCEPT AS A MINI MOVIE THEATRE LUXURY or REVENUE GENERATOR

What will have the most value?
Bullet making equipment
Horses and livestock

The sound of commerce will be pots clanging on the sides of asses, people.

Anonymous said...

The battery's dead: Scientists invent wafer-thin plastic that can store electricity

Hoskald said...

Here is link to the 2008 US Government report on EMP,"Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack",
It is very informative and concerning. They are estimating that a 300 mile high burst would take out most of the US infrastructure resulting in 70 - 90% loss of life in the first year following the attack.

Give that, what I would put in a Faraday Cage would be a couple of 12v batteries, HAM HF radio (160 - 6 meters), some solar cells and a laptop loaded with off-line how-tos, like black smithing, digging water wells and herbal medicine. And move out to the country now. If you are stuck in an urban area when this thing goes off, you're basically screwed.

Mark A. Taff said...

The power wires are more than robust enough to survive *any* possible EMP. The parts that will fail are some smaller transformers, switching stations, and electronic monitoring and control systems and such. The wires themselves can easily handle 50-100 KV.

Wire mesh might be fine as an EMI shield, but it isn't going to do squat for EMP. For EMP you want solid Cu, Al, Ag, or steel sheeting at least a fraction of a mm thick, brazed into a box, with a lid that conductivly seals.

Then since it is nigh impossible to actually construct a Faraday cage without EM holes in it, you will want to make a smaller Faraday cage inside the first.

For gear to protect, I would protect a Petzl LED headlamp with rechargeable batteries and an solar charger, my TI-89 for calculus & algebra, my digital multimeter to help repair/bypass fried electronics, hand-crank flashlight, hand-crank AM/FM/Weather radio, digital calipers, digital gram scale, and my clock/calendar/weather station.

I would also protect any lasers, electronic sights, and night-vision devices for my firearms.

Htos1 said...

This is the real scaenario:

I said...

Honestly, a cell phone is probably the ONLY thing I would keep in a Faraday cage in the event of an EMP. Okay, well that's actually not true, I'm sure there are batteries and other such devices I would want to protect additionally. And yeah, I know cell towers would be useless. Not to mention nobody else would have a cellphone, unless they also kept a backup in a Faraday cage, which I doubt would be a common occurrence. But here's the thing. I've heard lots of survivalists and preppers say that "knowledge is invaluable, mainly because it weighs nothing". Meaning; of all the items, tools and gadgets you can pack in your bag to keep yourself safe when shit hits the fan, knowledge is a whole lot more useful because it can save lives, and it doesn't take up any pack space. Now obviously, my survival kit will have some basic literature, a roadmap for the entire state, a brief field guide of edible plants, etc. But there is just soooo much you won't be able to pack. You can't bring entire volumes with you when you're trying to survive. It just wouldn't make sense to do that. Now think about the size of any smartphone out there on the market and the size of a micro SD card (which are upwards of 64GB now). Given the fact that hundreds of pages of PDF doesn't even put a dent in that stoarge capacity, the amount of information you could stockpile is ridiculous.

I also would prefer a cellphone to a laptop because the batteries are smaller, thus easier to charge. Solar phone chargers anyone? Sure, there are plenty on the market. Not to mention the portability. Backup phone + solar charger + several SD cards + backup phone batteries in a Faraday cage at home. And you can STILL fit all of that in a single pocket if you felt so inclined. If something happens, head home, you've got your electronic buddies still good to go and waiting for you, ready to help out, and you can just toss 'em in the pack and get the heck out of there if you need to. Laptops are generally much heavier and much larger. And if you know what you're doing, there isn't anything you can't do with a laptop that you couldn't do with a new smartphone (seriously, the hardware in those things is ridiculous). If this tickles your fancy and you're not sure where to go from here, I recommend anything Android, preferably custom ROMs.

In the type of world that would probably come after a large EMP blast, I don't think you'll have many opportunities to ask many questions when faced with a problem you're unfamiliar with. I dunno about you guys, but I plan on filling up a few SD cards with useful information.

Christine said...

Fact is, the US and most of the world are in no way prepared for a major disaster. EMP, Yellowstone blows, a major nuke.

The only people who even have a shot at survival are the government and their families.

We the people, are screwed.

TheRightMan said...

There is a one problem with cell phones - enemy can track its position so if you gonna use cell phone better be prepared for visitors.

Anonymous said...

No cell towers means no tracking, but if you are worried put it in airplane mode.

Unknown said...

Can capacitors be used to ground a Faraday Cage instead of connecting it to the earth / soil?

Maybe they can adsorb the energy?