15 Things You Think You Know About Faraday Cages But You Don’t

By Anne January 13, 2017 14:40

15 Things You Think You Know About Faraday Cages But You Don’t

This article takes into consideration only the effects of a nuclear EMP, not a solar flare. A solar flare would only affect any electronics connected to the grid.

#1. Will a microwave work as a Faraday cage?

No. If an EMP strikes, you will notice that all your electronic devices that you stored in a microwave oven will be rendered useless. The microwave is not a Faraday cage.

#2. Will a refrigerator work as a Faraday cage?

No, most refrigerators do not work as a Faraday cage. I tested mine, and it’s definitely not a Faraday cage.

#3. If I keep a backup mobile phone in my Faraday cage, will it work when I need it?

Yes, your phone will work perfectly. However, it will be rendered almost useless because the network will not be functional. The only form of communication after an EMP will be the radio. Click here to find out what radio you should keep in your Faraday cage. 

#4. Do I need to store batteries in a Faraday cage?

No. They will continue to work regardless and will just take up space in your Faraday cage. Here are the best batteries for survival situations.

#5. Do Faraday cages need grounding?


#6. Do I need to keep my solar panels in a Faraday cage?

No. The only part of the system you have to worry about is your solar panel inverter. Don’t worry about your solar panels; they will be fine. It’s best to buy an extra inverter and keep it in your Faraday cage so you can replace the useless one after the EMP.

#7. If I wrap electronic devices in heavy duty aluminum foil, will that work?

No. But if you wrap the cardboard box in which you bought them in heavy duty aluminum foil, this would be an effective Faraday cage. Here are the step-by-step instructions.

#8. Will flashlights continue to function after an EMP Strike?

Some flashlights will continue to function, and some will burn out. It all depends on the power and distance from the blast.

#9. Is a shipping container a Faraday cage?

Yes, but just remember that you can’t just put the electronic devices directly in contact with the metal. Some people board the interior of the container with wooden panels.

#10. Can I use this shipping container as a “Faraday garage” for my car?

Yes, you can definitely do that. Most cars fit in a standard shipping container, but just to make sure, go ahead and take the measurements before buying a shipping container.

#11. If you turn off your devices, will they be EMP-proof?


#12. Are airplanes Faraday cages?

No. Planes operate on the basic principles of lift and thrust, so they will become more or less gliders. They will be very difficult to control and most of them will fall from the sky and crash.

#13. How do I test an object to see if it will work as a Faraday cage?

You can test any device that you think might work as a Faraday cage with a radio. Simply turn on the radio and place it inside the device. If the radio is still receiving a signal, then it’s not a Faraday cage. If you don’t have a radio, you can use a mobile phone, but the results won’t be 100% accurate in the sense that if your mobile phone still rings, then it’s definitely not a Faraday cage, but if it does not, you can’t really be sure. You need to test it with a radio to be 100% sure you have a Faraday cage.

#14. Can you EMP-proof a car?

emp carYou could build a Faraday cage, but this would mean that you will either never use your car or will need to buy a new one. I’ve seen some pictures online of people wrapping them in aluminum, but as I said previously, it’s pointless.

Instead of making your car EMP-proof, I think you would be better off buying an old, cheap car that has an electric system that is a lot less vulnerable. Here are the top 10 EMP proof vehicles.

#15. Will a galvanized steel trash can make a good Faraday cage?

Yes, but the can has to close perfectly, and you will have to line the walls with cardboard.

You may also like:

You Will Not Survive an EMP Strike Without This

The Only Way To Get Antibiotics When SHTF (Video)

Where Not To Be During an EMP

9 Places Where You Could Recharge Your Electronics After An EMP

By Anne January 13, 2017 14:40
Write a comment


  1. Sam6 January 13, 16:17

    I was thinking of buying a metal garbage can and lining it with flex seal a rubber sealant. Would that work in a Faraday cage?

    Reply to this comment
    • dougnicholson January 13, 17:27

      As long as the top of the can makes perfect contact with the rim, yes. The FlexSeal would take the place of the cardboard mentioned in question 15.

      Reply to this comment
    • JDC January 13, 18:05

      You could do that, but it would be the expensive way. The most important thing is to ensure that nothing you are storing is in direct contact with the metal inside, and that the lid is fully seated. I use a slightly smaller round plastic trash can inside the metal can. You could even leave items in their original cardboard boxes, though I might check to ensure no metal staples in the box.

      Reply to this comment
      • Beachcomber August 22, 16:54

        So, are you saying you could place anything that would fit into the plastic can inside the metal trash can with lid , without wrapping any of the items placed inside, and seal the metal can and it’s EMP proof?

        Reply to this comment
        • left coast chuck October 29, 17:57

          Whatever you wrap the item you want to protect in, plastic or paper, it must be non-conductive. Some plastics are conductive. I would stick with wrapping paper.

          If you are old enough, you might remember when cords for appliances had the copper wiring inside the cord wrapped in paper to act as the insulating material. Paper is non-conductive.

          Reply to this comment
        • Johnny3 February 2, 05:06

          After much analysis over a few years, my conclusion is that metal garbage can lids NEVER fully fit tight to provide an air or watertight seal, thus probably not sealed to electromagnetic radiation. Therefore the protection is questionable. To improve the seal, I recommend at least two to three very carefully applied passes of METALLIC [like actual metal DUCT tape] tape around the lid/can junction. And… it would not hurt, in addition to the cardboard or non-conductive can liner, to carefully wrap/fully seal each item in Aluminum foil.

          These two enhancements cost little, and it’s better to be safe than sorry.

          Reply to this comment
    • Illini Warrior June 14, 15:46

      lab testing on metal garbage cans have shown that the lid to body connection point is open to wave penetration – testing with a metal tape overlap at the junction point proved effective – for the re-usability factor a joint fill with 000Fine steel wool was also effective ….

      Reply to this comment
    • jack October 30, 02:23

      Guys (&gals).. First, research what the difference is between static electricity.. compared to power (such as AC and DC). Learn what AC is. I ask people and they brightly tell me “Alternating Current”! so I ask, WHAT is Alternating Current?.. and they are then puzzled, have no idea! Find out people! If you look it up you will likely remember it better and things will make more sense!
      Anti Static bags are just that. Anti static. They are typically a plastic.. perhaps Mylar.. with an aluminized film inside. They are not a metal container.
      Please understand, electricity doesn’t just flow because its there. Neither does water! There must be a difference in POTENTIAL. Water flows downhill because gravity provides a difference in potential. It had POTENTIAL energy. FLOW creates KINETIC energy.
      Why does a bird not get zapped when it lands on a high voltage wire? BECAUSE THERE IS NO PLACE FOR THE CURRENT TO TRAVEL, no difference in potential. Now, if the bird on the high tension wire touches (or in many cases, just close enough to draw an arc).. to a wire that is grounded OR of different potential.. ZAP and the critter gets fried! Iv watched squirrels play around HV transformers on poles.. always wondering when that day will be when I will witness a squirrel bridge the gap from the high voltage side to the grounded side.. and SEE the ZAP! So far, Iv never witnessed such! but the danger is there!
      That anti static bag is designed to prevent any areas of different potential.. so that there is no difference in potential that might be placed across the contents inside.
      IF you use one of these bags, well, Iv never tested them but I would be surprised if they provide anymore then about a 3db attenuation in an EMP. For those who don’t know, 3db is a double in power if an increase.. or a cut in half when you are attenuating.
      IF you choose to put your faith in an AS bag.. wrap the item in something insulating before putting it in the bag.. as many have stated. If you choose to use multiple bags (same applies with wrapping in any foil.. or even if you put one can inside another).. you need to completely insulate between each bag/layer so that there is NO contact between each layer. If not, then those layers touching.. become but ONE layer. Insulate between each layer!
      Folks, you’ve got to understand; there is no magic in the metal that protects from an EMP. The metal simply creates a COUNTER magnetic field .. CAUSED by the magnetic field that created it in the first place.
      IF you take two magnets .. where the fields are LIKE, they will repel. Even see a magnetic field map? the lines of force CURVE, bend AWAY from each other… Now, have you ever wondered WHY a transformer “hums”? (no, its not because they don’t know the words!).. Or, how a brushless AC motor works.. when there is no brushes?? Same principle of a Faraday cage! The motor has a winding.. this induces a magnetic field INSIDE that brushless rotor. OK, that magnetic field causes an electric current in the brushless rotor.. and as that current flows in that brushless motor.. guess what? it then creates its own magnetic field. This field is in direct opposition to the magnetic field created from the power… repelling each other.. very powerfully. So, it rotates.
      Transformers are similar.. you have a primary where power makes a magnetic field.. inducing a field into the secondary.. When power is used form the secondary, the flow of current thru the secondary creates a counter field that repels the primary field.. so they are always fighting each outer when there is power being used. Notice that the more the load, the greater the hum?
      Folks, if those currents are caused to flow so that the resulting magnetic field does NOT oppose the source, you will have holes in your protection. If an EMP causes the a current on the outside of a metal box.. and it is blocked by a painted surface so that the current flows AROUND a lid.. or safe door.. then that counter current is CHANGING DIRECTIONS… and thus your magnetic field will change directions.. and NOT be directly repelling the source (EMP).. resulting with “holes” where EMP is much less attenuated..(can penetrate). So, NO, the only way a safe can be good for EMP protection is if you make sure there is a current path DIRECTLY ACROSS ALL SURFACES.
      If you have a metal box.. metal walls, roof, floor.. you MUST make sure all corners are continuously conductive along ALL seams.
      Grounding has NOTHING to do with the function of a Faraday cage. IF the faraday cage becomes statically charged (relative to the earth, where someone might touch it and get shocked).. then grounding is good. IF the structure is subject to lightning, then it is the same principle. Often, in military installations, you have gear that needs grounding. Some, because of radio type equipment.. some for equalizing (making sure there is no difference in potential that someone might get shocked by. There is much in the National Electric Code (250) on grounding and WHY we ground. Many will not understand much of it.. but it is these things that might require grounding of a building built as a faraday cage.
      An EMP (E1) is a pulse.. with a VERY fast rise time. Research waveforms .. wave forms, in short, are mixtures of frequencies. Faster rise times of a pulse.. are the highest of frequencies part of the pulse… the long part of the pulse.. is the lower frequencies. The higher frequencies will have least energy in general… Having long ground straps.. can easily act as antennas, resonating (why are antennas TUNED to a given frequency? to be RESONATE!).. IF you ground your faraday cage.. do it with VERY SHORT, LARGE conductors… and I would ground it very frequently. Might also deliberately stagger your ground locations.. random locations.. to avoid resonance. In most cases, Id just avoid it unless you have some OTHER reason to ground.
      This is already to long folks.. but it would take a great deal longer to put it all together.
      Personally, I would NOT choose to use AS bags. Who will you go to when your electronics fails because you heard someone say it would work? Is it worth the risk? Im not saying it will not work. Most anything where you wrap in foil will help at least a little.. Remember, you are not preventing EMP.. you have to attenuate it to a level of little or no damage.
      I have explained much of this several times previously. There are several of us out there who DO understand this. It is always my wish that as many folks as possible will be genuinely prepared. I strongly recommend communications equipment be at the center.. and suitable things like laptops, printer.. to continue functioning, helping others.
      I keep near endless files on all kinds of data.. in digital form, either on portable hard drives (generally NON mechanical types).. or on SDS cards.. and I lock them away in multiple layers.. And when I need to recall that manual on my diesel generator.. or the load for my 308, 375HH, 454 Casul, etc… or that recipe for making a certain cheese… I can pull it up, print it, and go. My library is way to large, heavy, and non portable to do otherwise. I keep a few ammo cans full of printer supplies (and use a printer that runs on 12vdc.. and uses refillable ink cartridges so I don’t run into
      unavailability. Ever.
      I try to stay available.. and I always tag the “Notify me of follow up comments” box so if any of your responds I get a notice. So, if you have questions, I always try to respond back.. But please do a little digging as Im frequently going thru a long explanation for the same things.

      Reply to this comment
  2. bugjuice January 13, 17:15

    If I put a metal roof and metal siding on my house, what else do I need to do to make it EMP proof?

    Reply to this comment
    • BillH January 14, 17:08

      Unfortunately, to make a proper Faraday cage, it has to conduct on all sides. So it would need a metal floor. Also, it is critical that there are no seam gaps, as they actually act as antennas to draw the EMP into your cage. The entire surface has to conduct with no breaks so that the currents induced on the surface of the cage are free to exactly match the EMP wave.

      Reply to this comment
      • CapitalistPig January 16, 22:40

        My man camp house I bought has a metal roof,walls and a metal frame and studs with the interior being a plywood floor and sheet rock walls. I’ve tried to pick up my Wi-Fi outside and its not possible. Could I be protected from EMP?

        Reply to this comment
        • BillH February 23, 02:53

          Not likely. Floor that doesn’t conduct, windows that don’t conduct, and any seams that don’t conduct are issues. It might help protect from EMP some from blocking the waves, but that does not constitute a Faraday Cage.

          Reply to this comment
        • joe October 24, 01:53

          no, not even close, any gap over a millimeter is enough to allow an EMP pulse to get through. that includes windows and doors.

          Reply to this comment
  3. Don January 13, 17:37

    Will my very heavy Browning gun safe make a suitable faraday cage?

    Reply to this comment
    • Kirk January 20, 00:10

      It will help a little but there needs to be a proper metal seal on the safe instead of the rubber one safe makers use.

      Reply to this comment
    • Jack January 16, 03:49

      Read above!
      Its not how heavy.. it MUST be conductive all the way around; The door MUST be conductive TO THE BOX AT ALL POINTS AROUND THE DOOR. (not the door pins but as if you welded the door closed; current induced into it in a circular pattern must not be directed to go up or down to a contact point but MUST be conductive at every point on the door). Read my other post. Read RayD’s post where he talks of “Skin Effect” I failed to call it Skin effect but talk of the exact same thing.

      Reply to this comment
    • Jack October 30, 02:26

      Don, I did a kind of a combo response.. above… answering your question and others.
      Thanks for your question!

      Reply to this comment
  4. Sertbro January 13, 17:46

    Just a quick Thank you for providing the many tips and pointers. It’s always better to obtain knowledge and devices, then to wish you did if all hell happens.

    Reply to this comment
  5. Hamgeneral January 13, 18:20

    YES absolutely, the faraday cage needs to be grounded!!!

    Reply to this comment
    • Fc January 13, 19:27

      I used to work in communications in the USAF. Our faraday cage was grounded.

      Reply to this comment
      • Rod January 13, 22:06

        I am involved in EMP preparedness and grounding can be a very tricky thing with shielded containers. If the ground wire/strap is too long it can actually become a very good antenna for the pulse. Since the pulses are in the microwave range, you can see that the connection is going to have to be very short to be effective, hence not having things grounded might be better for the civilian. I also have grounded containers but the grounding schemes for those are very elaborate and not easily accomplished by the normal DIY’er.

        Reply to this comment
      • SailorSam January 13, 22:18

        The larger the cage, the larger the cable needs to be and the deeper the ground. You will need to dissipate a lot of current.. The closer to the EMP the stronger the field, the more current generated.

        For US Navy SatComm tech.

        Reply to this comment
      • BillH January 14, 17:13

        If the primary objective of a Faraday cage is to prevent leakage of information out of the cage (a very common military need), then grounding is a good idea. But the Faraday principle does not require grounding, only an unbroken conductive surface. Grounding causes the currents induced by the EMP to NOT mimic the wave correctly. Grounding uses a different principle to provide protection — bleeding all of the power into the ground. Which is very different from, and somewhat inconsistent with, the way a Faraday cage works. See also Rod’s remarks below, which is another way of looking at it.

        Reply to this comment
      • Jack January 16, 03:54

        May need to be grounded for some other reason.. but in a properly designed faraday cage.. grounding is not necessary.
        I have many years working for DOD.. and am a US Navy veteran. I know there are reasons for grounding beyond what is needed for faraday cage.

        Reply to this comment
    • Kirk January 20, 00:11

      No, it doesn’t. A faraday cage does not need to be grounded. See how much bad information is floating around?

      Reply to this comment
    • Jack January 16, 03:14

      Opps! I made references too “Rod”.. But I meant RayD.

      Reply to this comment
    • left coast chuck October 29, 17:48

      Dr. Arthur Bradley, who has done extensive testing on electric pulses and Faraday cages has stated that it is not necessary to ground a properly constructed Faraday cage.

      He has just posted the results of his quick and dirty testing of a Conex box (shipping container) as a Faraday cage. His tests revealed that the Conex box will act as a partial Faraday cage.

      All who are interested in protecting electronics really owe it to themselves to buy his book about EMP/CME. He has conducted various tests on protective material and has reported the test protocols and results so that you may judge for yourself whether it is an adequate test or not.

      Interestingly enough, he found that ordinary duct tape worked better sealing garbage cans than the expensive electronic tape that he used in a different portion of the garbage can test.

      He points out that it is not necessary to completely exclude all electronic penetration, just to reduce it to the level that is lower than the destructive level that will burn out the electronics. That’s nice to know but for the average guy like me, not knowing how to test my computer to see what kind of voltage it can take, I have to rely on trying to completely seal the thing off from all stray voltage.

      Reply to this comment
  6. Outlaw Josey Wales January 13, 19:38

    How about computer anti-static bags? Logically I think they should work but you’d probably need to wrap them around the devices a few times. I work for a computer company so they are literally everywhere and free to take after they’ve been used.

    Reply to this comment
    • Sean September 7, 18:52

      Yes anti static computer bags work, but they should be sealed and nested within each othe. ( device wrapped in bag 1, then bag 1 put into a larger anti static bag etc.) The more nests the more effective. But most AS bags only decrease the Db by 10-15, and your looking for-50db – – 75db shielding for an EMP. SO… device in 2-3 nested AS bags , put into a metal trashcan lined with cardboard ,sealing the lid on with metal tape should give -10,-10,-50db ( -70db) protection to -15,-15,-60( -90db) protection. Also testing with radios is not ideal, the wavelengths used are different then an EMP, though they can give a gauge as to the shielding provided.

      Reply to this comment
  7. don January 13, 20:30

    What do you recommend for a reliable Walkie Talkie, a CB, and a HAM radio?

    Reply to this comment
  8. N. Tesla January 13, 23:56

    Why don’t airplanes fall from the sky when hit by lightning?

    Reply to this comment
    • BillH January 15, 01:47

      An airplane is, to a significant degree, a Faraday cage. It has a conductive surface. However, there are sizable gaps in that conductive surface. Certainly the windows. And the doors may not be designed to allow conduction all around the edge with the adjacent surface of the plane. These problems can be solved and are solved for Air Force One, for example. But not for private aircraft.

      A lightning bolt will be conducted around the windows and doors and not enter the plane, as it is seeking the best conductive road to ground. But an EMP wave will enter through the openings, as it is a wave traveling in a straight line from its inception. It is not seeking ground any more than any radio wave is seeking ground.

      Reply to this comment
  9. Dave O January 14, 02:03

    What about army surplus ammo canisters, they are metal and close very secure, also come in many different sizes.

    Reply to this comment
    • dougnicholson January 14, 02:22

      The link in tip #7 discusses this.

      Reply to this comment
    • BillH January 15, 01:55

      Unfortunately, the info in the link from #7 above is incorrect. An ammo can does not normally have a conductive connection between the can and the lid all the way around. Which is a requirement. The entire surface must be conductive, with no non-conductive seams. Conductive tape all around the lid would help, but only if the paint was removed from the surface where the tape sticks to the lid and the sides. The only real alternative to make it work correctly would be to remove the rubber gasket and replace it with a conductive gasket.

      So the basic answer is no.

      Reply to this comment
      • Mj September 19, 01:25

        What if you bury said ammo can under say the patio in a back yard

        Reply to this comment
      • Jack January 16, 03:08

        They also say a container is a suitable faraday cage.. WRONG!
        First, it has a WOODEN FLOOR. Second, it has RUBBER GASKETS on the doors.
        A faraday cage is only protective IF it is completely conductive on all sides, and can carry current across EVERY MILIMETER of its seems so any electric current induced into the box is not blocked causing it to flow in a direction that it is NOT induced to continue flowing. Take an ammo can.. Yes, the lid is conductive.. and the hinge and latch will ground the lid.. but an induced current that causes current to flow from the bottom, up the side of the box.. then gets to the rubber gasketed lid and has to CHANGE DIRECTIONS to get to the latch in order to carry across the lid. This change in direction KILLS its potential as a faraday cage. The current MUST be able to run UP the side of the box.. then DIRECTLY onto the lid COMPLETELY ACROSS THE SIDE OF THE LID and across the top in the same circular direction.. This current is generated BY the inductive field (EMP in this case).. and as this current flows it creates a magnetic field at 90 degrees to the current. This directly opposes the magnetic field that created it (the EMP).. and is what causes the shielding effect. When you run the current in a different direction you turn the magnetic field as well… and wherever the current direction is forced to change, the magnetic field will no longer directly oppose the EMP source. You could call this a “Leak”.
        This skin effect field does not need to be grounded to work.. and improper grounding may very well act as an antenna bringing MORE EMP to the faraday cage.
        In a Container, the wooden floor has steel spans under the wood but again forces current to run in certain directions as described above. The wood does nothing to block radio waves from getting thru.
        E1 generally last from a nano second (one billionth of a second) to possibly several microseconds. There is an E2 and E3 .. but the E1 pulse is the one I mostly consider.
        Interesting thing about pulses..
        How can you tell the sound of a musical note from one singer to another? HARMONICS.
        Waveforms are a make up of many frequencies combined together. A square wave has a fundamental frequency and (technically) an infinite number or odd harmonics. But your voice is not a square wave! but it IS a combination of fundamental frequencies and harmonics. And that EMP pulse is similar.. it has a fundamental frequency (even if only a half wave).. and other frequencies.. combined to make the waveform. Part of it will be VERY high frequencies.. all the way down to very low frequencies….
        Now.. I forgot where I was going with this! None the less, I hope this aids many in understanding faraday cages, pulses and frequencies.
        Of note, higher frequencies tend to permeate the ionosphere.. as you do down they bonce and are reflected down to earth.. just “like” a radio wave. Lower frequencies tend to follow the earth.
        Personally, I believe Compton Electrons are the primary source of an EMP.. Compton Electrons are electrons stripped from their atoms in the atmosphere caused by the violent blast. When you get electrons moving, they create a magnetic field…
        I wouldn’t be surprised that Rod, a PhD in electrical engineering, might be more knowledgeable in this area.
        Thank you Rod.. for the unintended vindications (comments on other threads Iv made). I don’t have a PhD but been dealing with radio and radio waves for over 50 years.

        Reply to this comment
        • left coast chuck February 9, 23:51

          Did you read my post about Dr. Bradley who had just conducted actual tests on a shipping container to see if it would act as a faraday cage? He found that it partially protected electronics inside the container. This was a hands on test conducted by a man with both the on the job experience as well as the academic theoretical knowledge. He has done extensive testing which he described in his book on what makes an effective faraday cage.

          Most of the posters to this link, including myself, are babes in the woods when it comes to electronics. If your knowledge is 20 years old, you are as out of date as Rip Van Winkle.

          We can read about the effects of the Carrington Event CME and later CMEs. We can read about the effects of Operation Starfish on electrical components several hundred, if not in excess of a thousand miles away back in the 60s. Some of us have managed to short out electronic equipment through careless handling of static electricity.

          But in the end, when it comes down to protecting against such electronic events, we are five blind men describing an elephant. Arthur Bradley has a keen interest in protecting against those effects I described. He has actually conducted measurable tests of the various containers people have talked about. He has published the parameters of those tests and the results.

          Instead of relying on the advice of an ex-air force electronics technician whose electronic experience was during the Viet Nam war, why not consult a current expert who has done real life experiments with reportable results?

          Reply to this comment
          • joe October 24, 02:05

            First, did he have the ability to generate a real EMP pulse of several thousand volts? If not then his tests are worthless. There were tests ran on cars, that said that most survived. Their test was at least a thousnad times too weak to be actually useful. Even the best military tests fall short in that the pulse is not as strong as a real EMP pulse would be.

            Reply to this comment
  10. RayD January 14, 03:02

    Some good information here, but a few that are incorrect. Faraday cages and shielding must consider the frequency they are protecting against. High frequency signals are protected just fine with aluminum (or copper or silver). Seams in the seal are leakage paths. Low frequency can couple through aluminum magnetically despite this and need a ferritic shield (nickel, iron, or steel). Your best bet is an aluminized shield within a steel container, i.e. a metallized plastic bag inside a gun safe. Note that the seals on the gun safe can allow leakage, however. This is what probably killed your refrigerator idea. Aluminum or copper tape on the seals can solve this. Also, grounding is NOT required with a good Faraday shield. (PhD Electrical Engineering)

    Reply to this comment
  11. Ron January 14, 05:04

    Does a Faraday cage need to be grounded at the bottom? Is the EMP line of sight and will not reflect from below the burst?

    Why would aluminum not work as shielding?

    One of you commenters said you need to ground the cage. You said you do not need to ground it. Which is correct?

    Reply to this comment
    • BillH January 15, 02:05

      Does not need grounded. See comments by myself and others. EMP is line of sight. It will not travel through a hill or mountain or over the horizon. Aluminum will work fine as shielding for high frequencies, which is the main concern from EMP.

      Reply to this comment
      • Johnny D September 19, 06:50

        Hey BillH,
        I agree and disagree with your Line of Sight. I agree the effect is line of sight, but disagree with where that line of sight is measured from. Since the Compton effect is generated in the Ionosphere and regenerated downward I think the EMP effect will be horizon to horizon where the blast meets the Ionosphere and then downward toward earth… making mountains for the most part ineffective. I am stretching my mind here… but I think that is the way it works.

        Reply to this comment
  12. RadD January 14, 07:48

    A Faraday cage does not need to be grounded. Grounding provides a discharge path for the Faraday cage, but neither helps or hurts the items protected inside (unless the internal item is touching the cage at more than one point). Reflections occur from everything, creating both constructive (hot spots) and destructive (null spots) interference patterns.

    Electromagnetic radiation is attenuated by distance and material (shielding) in the path. So it is more attenuated when not a direct line of sight, but is still present at a lower power level.

    Electromagnetic radiation has both an E-field (electric) and an H-field (magnetic) component. E-field dominates at higher frequencies, H-field at lower. Aluminum works fine for higher frequencies, steel for lower frequencies. The item inside the cage can be in contact with the cage, but only at a single point. Otherwise, a voltage divider is created and part of the energy flashes through the device you are protecting.

    Reply to this comment
  13. MKS January 14, 10:40

    More self proclaimed experts who don’t learn anything. At the very least read MIL-STD-464 and 188.

    Reply to this comment
    • BillH January 14, 17:50

      Um, MIL-STD-464 is related to electronic safety. MIL-STD-188 is related to electronic communication standards. Neither addresses EMP at all, except by reference. MIL-STD-2169 is the EMP standard, and it is classified. You negative attitude toward your fellow bloggers appears without foundation.

      Reply to this comment
  14. Samp January 14, 12:41

    There are few absolutes when discussing EMP and things used to protect devices from its effects. Some of your 15 points are not necessarily true. There are some very good videos out there that are made by SCIENTISTS using SCIENTIFIC TESTING METHODS that put EMP into perspective. I encourage folks to do more research on the topic and not rely on this article for direction.

    Reply to this comment
  15. steven January 16, 19:28

    and right there show this tech is trash and we need to get back to the old .not tech shit that will soon fry .grr

    Reply to this comment
    • Rod January 16, 21:31

      While I sympathize with your sentiments, having been involved in EMP preps shows me the downfall of this idea. Yes, the equipment would most probably survive, but it is also extremely power inefficient, which would require a larger power source (genset, since no commercial power available) which would also require more fuel, which will be hard to come by since many of the pumps would no longer function. Best is shielded solid state with a smaller shielded genset and as much fuel as you can get your hands on, yet still keep viable.

      Reply to this comment
  16. KP January 16, 22:16

    If I store a spare computer for a 1992 Ford Ranger (pre-programmed) in a Faraday cage will my truck run after an EMP?

    Reply to this comment
    • Rod January 16, 22:32

      Best answer I can give is “Maybe” because when you are talking about EMP there are as many variables as there are when you deal with lightning. If you are right under the burst (assuming nuclear device) then you will probably lose the alternator and starting motor and other things with coils of wire. Farther away from ground zero the effects diminish. It also depends on the strength of the pluse. There is also a school of thought that says that computers in vehicles are shielded, but I take that with a grain of salt, personally. My choice is an early ’80’s model diesel before the advent of electronics, all mechanical fuel system. With a spare starter, solenoid, and alternator stored in a protected enclosure, you should be able to get it going after a few hours work.

      Reply to this comment
  17. CapitalistPig January 16, 22:41

    My man camp house I bought has a metal roof,walls and a metal frame and studs with the interior being a plywood floor and sheet rock walls. I’ve tried to pick up my Wi-Fi outside and its not possible. Could I be protected from EMP?

    Reply to this comment
    • Rod January 16, 22:49

      I would say no. I have seen an EMP protected shelter and walls, ceiling, and floor are all conductive. Door is VERY special and built to seal when closed. Other openings in the building as well are closed with finger stock grounding. When you are thinking of EMP think of an extremely close and powerful microwave dish pointed directly at you with many, many watts of power. You can see that it would punch right through any unsealed gaps in metal and would go through glass and wood as well. Sealing a building for EMP is a study in engineering, both mechanical and electrical.

      Reply to this comment
  18. vocalpatriot January 24, 16:24

    Lots of incorrect and plain dumb information in this article. I don’t recall news of any airplanes falling from the sky when hit with lightning or C.M.E.s .The skin effect, which is the principle of how a Faraday cage works, does protect the electronics on planes and in cars to some degree, you will find that cars are better protection than most believe. it isn’t an all or none situation…further..just buy spare modules in case the ones in your car DO fail, maybe the radio, too. The rest of the car will likely not be affected..but, cheap insurance. HOWEVER, because of the windows and doors on these vehicles, anything stored in them won’t be protected enough. Microwaves actually ARE Faraday cages BUT are designed to keep specific frequencies inside and E.M.P.s are broad spectrum bursts with HUGE levels of power. So, a chicken wire Faraday cage will not work. There must be no gaps in the conductive cover. even a small pinhole or slit can allow some damage. This is why a metal trashcan or altered ammo can would be the best bet. Also I’m not buying the tinfoil on the box trick, because the amount of power involved may render it “invisible” to the emp. It could act as a capacitor and simply pass the energy right through. Mass will your friend..thick metal boxes and cans would be your best bet. Insulate the stored items with plastic or cardboard form the inside surfaces of the cage and the further from the side wall the better.
    Good luck danger rangers!

    Reply to this comment
  19. Johnny D February 3, 07:10

    After reading the 15 and the comments… for the most part I think the information is accurate (especially as corrected in the posts). What I was surprised by was the comment indicating Solar Panels would stand a chance against the E1 emissions of an EMP. Fundamentally, solar panels are arrays of semiconductors where the gate lengths are quite small (not as small as communication equipment or computers…but I would think still susceptible without protection. Thoughts?

    Reply to this comment
    • Rod February 3, 17:11

      I have seen this same idea in a number of venues and have my doubts as well for exactly the reasons you stated. I would really like for someone to do some 3rd party testing so we would know for sure. It is possible to do this with EMP generators made specifically for the purpose and used every day testing EMP shielded facilities. Not sure I would trust a manufacturer’s claims without seeing the test methods and data.

      Reply to this comment
      • Johnny D February 23, 04:56

        Hey Rod,
        I haven’t seen any manufacturer spec out a semiconductor for EMP. Keep in mind that the very physical characteristics that define modern semiconductors for fast/low power use (gate-length) is the very characteristic that E1 attacks. Normal zenar diode protection (for anti-static damage) is too slow for an E1. static electricity damage is more E2, or lightning effects (much easier to protect against…oh and the principle reason why planes are fine in a lightning storm). With respect to Faraday Cages… The casual enthusiast really just doesn’t get it. A screen room (a real Faraday cage, spec’ed out and tested for emissions) is a big deal. A metal box (electrically) is not that easy to accomplish to protect against a broad spectrum event. I like the metal trash can, but even with that, seal all metal junctions with aluminum tape and a non-conductor liner on the inside AND a shield bag for your goodies. I am figuring that combo should give the enthusiast about 50dB of protection.For the cost benefit, I have seen nothing that even comes close.

        Reply to this comment
        • Rod February 23, 16:50

          Johnny D. I agree, but have to tell you that the professionally made shielding that I am familiar with is nothing more than a steel box with fingerstock on the doors and the items inside are bonded to this box without any insulating material at all. I have been suggesting to those without a lot of real world EMP experience to use a galvanized trash can, sealed with aluminum tape, stored in the lowest part of the building, such as a basement. Depending on their distance from the detonation (if it an EMP device) that should get them by unless they are right underneath and then most things will be toast anyway, even the professional stuff.

          Reply to this comment
          • Jack January 16, 04:36

            Finally, people who DO get it! But.. Iv read your other comments.. I just want to say to others to look to you, JohnnyD.. as someone with GOOD answers, and I think you, Rod, have also been accurate. (Not to sound like all just figured it out but rather, I completely agree with your observation and knowledge.
            I would say that the higher the frequency of the E1 pulse, the weaker it would be (the E1 pulse being a waveform consisting of many frequencies.. as I wrote in another place).. I think the steel wool in the can to assure a very consistent conductive contact.. is a great idea.
            RayD had some good, right on explanations I liked as well.
            I have about 12-13 years working under DOD.. worked on EMP systems for DOD.. and have over 50 years working with radio electronics, Im an extra class ham.. and Im a retired commercial electrician as well (but this reflects more on power & grid systems)… but Iv don’t a lot of other things beyond this.
            I would argue the concept that a pin hole would be damaging.. yes, it COULD but would be unlikely. For instance, in power plants they must have fresh air for the diesel generators.. and exhaust ..
            Here we get into waveguide considerations on the technical side.. but in practice air input is achieved by a series of square tubes (I would imagine round would be OK too).. but in reading they must be at least 5 times in length of the smallest wave you are trying to keep out. In practice, these vented to inside another all STEEL lined area that would generally absorb most of the radio (EMP) energy bouncing around before they got to the location where they could go down a tube. Waves do not go bounce around a irregular steel plenum.. then by the time they can go thru the designed length tube.. little energy is left. This plenum is steel.. and it IS GROUNDED. To this end, grounding is required.. but it is NOT an faraday cage but rather is designed to absorb/attenuate EMP energy, especially higher frequencies.
            Iv seen screens as part of a protective cage.. but they are very carefully designed.
            Thanks guys for your input! Hope others will read your comments!
            Somewhere, someone shunned the use of cardboard because it can give capacitance between the protected item and the faraday cage.. Got to write on that..

            Reply to this comment
            • JohnnyD January 28, 06:53

              Hey Everyone,
              So I had an interesting suggestion made to me regarding solar panels and EMP. My previous position was that because of the sensitivity of the Gatelength (for FETs) and PN juctions (BJTs) they would all be fried. But the question was brought up, how does the energy get in?. IF we use an antenna models (a very reasonable approach), then we define the on-wafer conductors (wires between transistors) and junction networks conductors as antennas, what frequency would they be tuned to. Of course each architecture would resonate with a different set of frequencies… but generally speaking, the conductor lengths would be very short, corresponding to frequencies in the GHz or even 100s of GHz. The E1 is a broad spectrum, high frequency component of EMP, but as frequency goes up, the E1 gets more and more weak. So, maybe there is a chance panels not connected to the grid, or not connected to your home, would survive without being in a Faraday cage…. Just thinking… Comments?

              Reply to this comment
    • Jack October 30, 02:19

      I have only my understanding of wave forms, electronics, electrical, mechanical.. Radio electronics over 50+ years.. but what I would say is WHY does an EMP damage electronics? Is there some magic in the waves?
      what is the common factor? most damage issues come from longer conductors ATTACHED or PART of the item subject to damage. WHY?
      Because the wires act as ANTENNA’s.. accumulating voltage and current… and conducting it right down TO the semiconductor devices.
      I don’t care how small a junction is.. its the amount of electrical current carried on it that does the damage. Solar panels.. or the mosfet input on my ham radio front end, connected to a suitable.. often large.. antenna.
      What are solar panels if they are not connected to a power system? So, you have wires connecting the solar panels. What are they if not antennas that can, potentially, act as antennas, collecting EMP and delivering it RIGHT DOWN TO THE SOLAR PANELS??
      I contend that its NOT the EMP damaging the PN junction of the solar panels… its the wiring absorbing EMP.. then applying it across the solar panels that causes the damage.
      Many believe that small hand held ham radios may well be OK if they are not hooked to large antennas like my larger HF rigs. And being DISCONNECTED from power wires and antenna lines… will probably be OK. Maybe. WHY? Because the WIRES are not connected.
      I contend solar panels will be OK if they are either NOT connected… or the wiring connected… is fully protected so as NOT to act as antennas, piping the EMP voltage right down to the panels…
      Solar panels have many cells connected in series.. and this alone can create a length of conductor that may act as an antenna, creating a voltage across the cells.
      I have a pretty good background on EMP research.. but NO ONE has offered me ANY reason for EMP affecting solar panels; Some try to tell me.. yes, it will destroy a solar cell.. others say it wont. But with these folks, they offer NO reasoning. So, with MY background I contend the above as it makes sense to me, someone with an extensive understanding, education related to the field, and related experience. IF someone has some technical information to the contrary, RESPOND with your reason!

      Reply to this comment
  20. riverrat February 25, 17:18

    Unfortunately the author seems to have inaccurate data For instance, shipping containerss have a wood floor which does not allow for protection. Solar panels have a diode that requires special connections after an EMP. Flashlights using bulbs not LED will work after an EMP. and much more.

    Reply to this comment
    • Richy December 2, 17:28

      Shipping containers are all steel with a wood floor on top of the steel floor.

      Reply to this comment
      • Bob June 10, 14:28

        Sorry, Richy. I’ve been in the shipping business +40 years and riverrat is correct. Shipping containers have a wood floor (treated plywood), screwed to metal cross braces on the bottom of the container. They are NOT solid steel boxes. Steel is heavy and shipping companies are not going to transport several hundred extra pounds of steel for no reason. Additionally, the double doors compress a thick gasket to seal them. Even compressed this gasket is about 1/4″ thick, so between the four sides and the split between the doors, you have a 40′ long, by 1/4″ ‘opening’ sealed only with compressed (non-electrically conductive) gasket material. That’s almost a one square foot ‘hole’ but it’s worse than that, because it is a long narrow slit which ANY wavelength will go through. Don’t believe me? Get a good AM/FM radio with good strong stations for both bands. Then have someone seal you in a shipping container and I’m pretty sure you’ll find you can listen to either station without interruption. Shipping containers CAN be made into Faraday cages, but only with a great deal of modification.

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  21. riverrat February 25, 17:23

    I forgot about the solar EMP, under the potential of a plasma blast, it would cause more damage than a nuclear blast from an electronics perspetive. Search on the plasma blast crater in northern Africa that many thought was a meteor crater!

    Reply to this comment
  22. Illini Warrior June 14, 15:37

    Rarely ever mentioned in regard to Faraday cages …

    since both EMPs & solar flares will undoubtedly have secondary followup events – the stored electronic items will have to be used on a “use & scoot” basis – quikly re-protected within the cage – Faraday cages need to built to an eazy access design …

    Reply to this comment
  23. Bruce September 7, 16:28

    I have a battery backup system with solar inverters located in a faraday cage. The room has several large wires that enter on three sides and the floor. The system is active, not just storage. I assume the wires are “conductive penetrations” that lower or negate the effects of the shielding. How can I mitigate the effects of these conductive penetrations?

    Reply to this comment
    • Rod September 7, 20:21

      Given the equipment available to the general public, there is no way to provide protection with outside connections like you are describing. Only complete disconnection will ensure maximum protection against EMP.

      Reply to this comment
      • Bruce November 10, 22:43

        Complete disconnection is not an option. How else can I mitigate the effects of these conductive penetrations?

        Reply to this comment
        • Rod November 10, 22:56

          Considering that EMP is of varying levels depending on distance from the generation mechanism, you plan for the worst. I know of no way to reliably and economically protect anything that has connections to the outside, power, ant, phone line, etc.

          Reply to this comment
        • Jack January 16, 04:44

          Look up EMP protection on the web.. there are many systems that are designed to protect such lines.
          I only scanned thru your entry.. so didn’t catch every detail, however I have been researching best ways of protecting communications cables, control cables, power wires..
          I would like to note for all.. EMP is NOT the same as a lightning strike. It is NOT the same as a CME. There is some common things in each of them but in most cases they ALL have different means of protection. Some elements of each can be applied ..

          Reply to this comment
    • Magi November 14, 21:22

      To deal with AC I suppose you could set something up to induce power from inside the cage wall to the outside, the coupling would be poor and the efficiency would be low but it would could work.

      The DC from the solar panels, however, is a big problem and I have no idea how it could be done.

      Reply to this comment
  24. Johnny D September 19, 07:04

    It might be benefitial to describe the components of EMP. E1 – fast pulse, E2 – slower but more intense, E3 – slowest pulse, but a titalwave of energy. When a nuclear detination occurs, all three are generated.
    E2 is probably the easiest to understand, it is similar to lightning…. well understood and most devices have protection in them for ESD (electrostatic discharge)… basically a small lightning bolt generated on the surface of our bodies.
    E3 – This is the slowest pulse (with reference to the raise time of the energy being transmitted), but it is generated in overhead power lines. The longer the line, the bigger the titalwave. With long transmission lines accross the country, each one will create huge electrical surges, they will pass right through transformers (destroying them in the process) and continue on down the line into each of our homes. It is this E3 that will destroy most anything plugged into your home outlets. Conversely, anything not plugged in will likely not be affected by E3. With a small amount of money (maybe $300) you can buy a whole house suppressor that will (by its specifications) protect your home electronics from E2 and E3. Further, CME only generate E2 and E3 pulses.
    E1 – These are the really nasty pulses. They are not very large (in energy content), but they are large (peak) and very very fast. As such most semiconductors will be susceptible to them regardless if they are plugged in or not. Since almost anything these days have semiconductors in them (transistors, diode, etc) they are all in danger. Keep in mind that LCDs are large arrays of semiconductors, solar panels are arrays of semiconductors, almost anything that gives off light these days are semiconductors. Semiconductor items need to be in a faraday cage for protection.

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  25. Johnny D September 19, 07:20

    I might also mention, most lay persons really don’t understand shielding. Keep in mind, it is not to shield or not to shield, but how good of a shielding job you do vs the susceptibility of what you are trying to shield. In order to make computers faster, the semiconductive area of the device is made smaller and smaller (last I checked commercial processes had the gate length of semiconductors down to 1/10th a micron (1 X 10-7 m). the smaller it is, the more susceptible it becomes to damage to energy. This might be the reason why cars (especially 90’s cars) might be OK. They are using robust semiconductors with fat gate lengths and a light amount of engine shielding. Having a spare car computer in your faraday cage is still a good idea!.

    Modern communication equipment has small gate lengths and thus are highly suseptable to E3. Thus they need to be well protected. In my faraday cage, I also put sensitive items in an ESD bag… keep in mind that for cage within cage protection to be effective, none of the individual cages (ESD bags or faraday cages) can conductively touch one another. Thus a design might be…metal trash can (with taped seams and cardboard insert), then an ESD bag, then a ziplock bag with your radio in it. Notice that the pattern is conductor, insulator, conductor, insulator… I figure 30dB on the can, and another 20 dB on the bag… giving me 50dB. I think the MIL-SPEC is talking to between 60-70 dB, but getting that next 10-20 dB is REALLY hard. With all my preps, I try to match cost with reality. Hope this helps everyone.

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  26. Billy October 3, 04:01

    What material defeats a faraday cage?

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  27. Johnny D October 3, 04:19

    Not sure I understand the question. the purpose of a faraday cage is to provide isolation from one environment to another. In the case of EMP, it is to isolate our normal electrical environment (where the damaging pulse is located) to a protected environment (where we want to protect items against the EMP).

    So, if you want to defeat a faraday cage, don’t build one and don’t put your electronics in it.

    IF you are asking what construction techniques undermine the effectiveness of a faraday cage, then I would respond that it is far easier to have an ineffective shielding than not. Any wholes in the in the container, any gaps that are not electrically sealed would contribute to the cage ineffectiveness.

    Did I answer your question?

    Reply to this comment
  28. Magi November 10, 22:12

    Speaking shielding containers, a very good container i a new and empty paint can (Home Depot), all joints are electrically good seals and the lid forms an excellent electrical seal, once closed the can is even water tight. All you have to do cover the inside with an insulator or wrap whatever you put in the can in an insulator. Of course, nothing is perfect, you have a limit on the the size or the items you can put in the container.

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  29. Magi November 10, 22:38

    A question for those in the know, how well does water work a an EMP shield? For example, if you submerge sensitive equipment in a lake/pond in a watertight container, would it be protected/safe from an EMP burst?

    Reply to this comment
    • Rod November 10, 22:58

      Now that is a question I have never heard before, and does raise an interesting point. I am going to ask those that know more than I do about this one!!!!

      Reply to this comment
    • Johnny D November 11, 04:30

      Hey Magi,
      What a great question. I’m not sure how water would work. My knee jerk response is that it should work great (assuming the water is conductive). I wonder what they do for EMP on submarines when submerged.

      Let me spend some time researching it a little.

      Reply to this comment
      • Jack January 16, 07:00

        Maggi, I do not believe water will make an effective shield. JohnnyD, HOW does that faraday cage work? In short, it creates a “skin effect” .. Where would you have a skin effect? the water may absorb some of the energy, how much will likely depend on how deep..
        If you managed to account for a skin effect over the water it would NOT be very dense.. and with the bottom half of the skin effect being the earth itself.. Honestly, I would NOT count on submersion in a lake to be very reliable.
        Does this make sense to all? Please, if you don’t understand about skin effect caused by the induced current created by the EMP.. read that first!

        Reply to this comment
        • JohnnyD January 28, 06:28

          Hey Jack,
          Yep, skin depth is important (dominant) effect on a Faraday cage. Water is VERY attenuative to RF energy as well as antennas work really poor in a conductive environment (physical relationship between conductor and ground provides the impedance of the antenna). A shorted antenna reflects all (well almost all) the energy. Interesting question though….

          Reply to this comment
    • Magi November 14, 21:12

      My “gut feeling” is that the protection would be dependent on the depth. Submarines have to rise close to the surface to transmit higher frequencies, i understand they’re able to receive very low frequencies at higher depths but EMP frequency should not penetrate very deep, but my gut’s been wrong before.

      Reply to this comment
      • Johnny D November 20, 04:59

        Hey Magi,
        Agreed… in fact, I think normal communication on subs, have antennas that are mounted in the parascope mast (getting the antenna out of the conductive water for use). ELF (Extremely Low Frequency) hugs the earth and can be received at depth.
        I still think that water (conductive water) would work well as an EMP protective device, just be sure to use an insulator on the inside of the container that is submerged. I haven’t looked into it yet, but it is on my list to research.

        Reply to this comment
      • Jack January 17, 01:33

        Submarines are nearly perfect faraday cages themselves… in the water or out (assuming no one left the screen door open when surfaced!).
        Actually, part of my background just happens to be working on US Navy nuclear submarines! And no, there is no screen door. I cannot share much because I don’t know what is classified.. but they are a complete steel envelope… and better yet is that they are cylindrical, not rectangular.

        Reply to this comment
  30. uncle December 5, 01:21

    What am I missing here, you talk about actual cages. cell phones under metal screens foil on the bottom and it will survive an EMP. okay you can see the items, that is not sealed correct, you can see the actual radio or cell phone? then you say metal trash cans will work as long as you have non conducive liner is between the can and the item you are storing in the can.will work great as long as it is a tight seal, I read as long as gaps are not more that 2″ you will be okay. There is an awful lot of [my perceived inconsistency here] how can a metal screen protect better than a trash can that might have a very tiny gap in the can . when it is stated the waves are 2″to 4″ and keep the gap less than?
    bird cages. 1/4″ inch wire fencing. some thing is not adding up here

    Reply to this comment
    • Rod December 5, 01:46

      Uncle, I can understand your confusion and I work with this stuff every day. What it boils down to is physics and the electromagnetic spectrum. Light, what allows us to see, has a very small wave length. EMP, all types, have much longer wave lengths. The copper screen in particular is a good example. Yes, you can see it because the light waves pass through the screen, and a grounded item, like the screen, does not absorb light, so all kinds of light squeezes through the holes giving you a discernible, but distorted, representation of the item behind the screen. EMP on the other hand IS absorbed and/or deflected by the grounded screen depending on the size of the holes in the screen. As long as the holes are small enough to block the entire wavelength of the EMP there will be protection behind the screen. As to the trash can, the can itself is not a bad field expedient shield, however it should have the lid sealed with aluminum tape to cover any gaps between the lid and can. Again, making sure any gaps are smaller than the EMP wavelength. Grounding these shields, screen, can, or whatever, is a highly debatable subject by even the learned. While grounding done absolutely correctly enhances the shield, done incorrectly it can turn the shield itself into an antenna, NOT something you want to have happen. My advice to the general prepping audience is trash cans, aluminum tape, and no grounding. I did not include insulating the inside of the can in that because the insulation itself can cause problems too. I have professionally shielded equipment that is not insulated on the inside but is grounded in a very specific fashion. I have no worries about it. One thing everyone needs to remember is that EMP lies between electricity that we use every day and light that we see every day. The physics displayed at each of these levels are very different and need to be dealt with in completely different ways. What might be a dead short using either DC or 120VAC, will look like an open circuit at higher frequencies. Vice versa is also true. All one needs to do is spend most of a lifetime studying and working with this to start to get an inkling of what is going on!!!

      Reply to this comment
      • uncle December 5, 15:16


        Very Very kind of you to reply so soon. My wife’s brother is in the army and his commanders are telling them to privately get their acts together. 13 Months ago he held an meeting with all of is siblings. bottom line we have about 3-5 month’s food. we bougth Mylar bags and a sealer. bought all sorts of beans of of amazon. bagged, beans and oxygen ab sobers then sealed the beans and rice. 115 gallons of water, various small solar panels and RAVstorage batteries and lights that are both battery operated or can charge another device. 30 rechargeable batteries solar cookers and today UPS delivered our Inergy kodiak. solar panels on the way I do want to protect those items. We have a heck of lot invested in the last 13 months that we never planned for. I have been looking a Lowes and home depot this weekend. the large tool boxes AKA job boxes heavy steel then use the copper door seals for the small gap even thought the gap is diverted in that it has a lip so the wave would not go directly into a box.
        I bought gun cabinet just steel cheap to store items. I tried the cell phone in it Yesterday to my dismay the phone rang while in the box. Do you think a jobber box will be any more effective. We live in a small place it has become very crowded with food, water, tents, at least 3 each bug out bags each, canopy’s [ not the delicious ones], 4 wheel carts, sling shots 5 flash lights each etc. I have terabyte drives with all of our stuff on them triple back up, We need to protect this stuff! The emp bags seem like more money out of our pocket and into others. I need some sanity in this .

        Thank for your kindness.

        Reply to this comment
        • Rod December 5, 19:18

          WOW! Sounds like you are definitely getting things together. As to the “gaps” in job boxes and gun safes, without going into exorbitant expense using copper fingerstock and other such items, I suggest using aluminum tape wherever there is gap in an item you are using to store things. A friend (who deals with this every day) has been experimenting with steel wool as a gasketing material. He has been getting mixed results.

          I also read through your list and would suggest that you make sure you have a variety of foods and ingredients so that you do not end up eating the same thing every day. That can lead to food apathy, which can lead to malnutrition, which leads to decreased mental facilities. I would also suggest you get a water filter so once your stores run out you can replenish them.
          Make sure you have a windup/solar radio as well. I use the C.Crane Solar Observer. I like the performance of the receiver in this radio, but I am a radio guy and that is extremely important to me!
          One other thing to remember is the prepper’s mantra. 3 is 2, 2 is 1, and 1 is None.
          I do wish you and yours luck in our uncertain future!

          Reply to this comment
          • uncle December 12, 04:19

            Rod, thank you I have many things you mentioned , C cranes radio no. I actually had a page open about it. but amazon reviews rated it below par. as many other crank radios it is getting frustrating too be honest.

            we do have different foods. from mountain house and others. water filters etc. ON EMP boxes we scored on the JOB box at HOME DEPOT walked out the store at $113.00 with wheels. someone returned it after a job and said it did not work . I hate that at the same time we did good. I have read, line it with cardboard. understanding the reasoning. I have read if you can put aluminum foil between 2 pieces of cardboard for better effect. (with that in mind) do you keep the aluminum foil how far for the edge of the 2 sandwich pieces of cardboard to give you EMP protection with out having the aluminum come in contact with that you are trying to protect?

            Reply to this comment
            • Rod December 12, 15:10

              Uncle, as far as putting cardboard or any other non-conductor on the inside of a metal box for EMP shielding, I am not entirely sold on that concept and I will tell you why. By doing that you are actually building a capacitor. Capacitors can pass RF right through them. When EMP strikes a metal surface the wave travels along the outside of the surface. This is called Skin Effect and is a well known phenomenon. Just because there is EMP on the outside of a container wall does not mean that the same EMP is on the inside. This is why dealing with EMP/RF is not intuitive. Different frequencies display different properties. If you have 120VAC on the outside wall of a container, you will have 120VAC on the inside because the frequency is so low. In my professional preps I have shielded equipment that is bonded to the shielding container by wide copper straps that are also grounded. These have been tested by professional, on site methods and do work. My best advice is to not get too fancy. Just make sure that any cracks or crevices are covered in aluminum tape. That should be sufficient without going to extraordinary lengths, like my professional equipment has to be done.

              Reply to this comment
              • Johnny D December 13, 06:02

                Hey Rod/Uncle,

                I agree that a cardboard insert, with a foil extra layer of protection would likely be more detrimental than beneficial. Sealing that second layer of protection properly would be a nightmare. I am a supporter of cardboard (only) to keep any metal inside of the box from potentially coming in contact with the inside of the outer shielding. As long as there is not a inside layer (or sandwiched layer) of a conductor, then there will be no appreciable capacitive effects (capacitors are two parallel plates separated by an insulator).

                You Tube shows (https://www.youtube.com/watch?v=uYWhTMmv6bs) the detail with which care must be taken when sealing a metal container and the effects of a poorly sealed cage. I use shielded bags inside my cage to improve isolation (isolation is additive in dB, so 40dB for my can + 15dB from my bag gives me better than 55dB of Isolation).

                Reply to this comment
                • uncle December 13, 19:59

                  Rod / Johnny D
                  Thank you! I am glad I found this site. You read so many things. it is hard to decipher which is good info and what is not.
                  I will watch video later tonight.

                  Reply to this comment
              • Jack January 16, 08:43

                Capacitors.. YES! You ARE building a capacitor! But just how much of a capacitor are you building?
                Capacitance is calculated as follows:

                C=0.224 KA/d (n-1)

                C= capacitance in pF (1×10[-12])
                {read, 1 times 10 to the negative 12 power.. this is one millionth of one millionth}
                K=dielectric constant of the insulator material
                A= area of the surface of ONE conductive surfaces.
                d= distance between the conductors in inches
                n= number of conductive plates (conductors).
                The conductive materials .. such as air, paper.. OR CARDBOARD.. makes a difference. Air is unity .. or “1”.. paper is 3. glass is in the 7 to 8 factor. the higher this number the higher the capacitance, all else being equal.
                By this formula, the greater the space, the less the capacitance..
                In short, I don’t think you would get a great deal of coupling using cardboard as an insulator.
                Polystyrene is rated 2.6 and polyethylene 2.3. If you are worried about cardboard, Id use some 1/2″ foam sheet. This will also put you further from the skin effect area as well.
                As stated by another, the reason you don’t want the chassis of your protected device to touch the faraday cage is mostly because if you get a second side touching you create a secondary current path THRU the chassis of the “protected” piece.. and if you get current flowing thru the chassis.. you also get that magnetic field INSIDE the item. Best to avoid ANY contact with the faraday cage.
                Taping with metal tape helps attenuate.. but the adhesive holding the metal tape .. none of it creates a current path … leaving you with mostly an attenuation cage, not a faraday cage. However, if you have a small split on a corner of a faraday cage.. metal foil tape will help attenuate the EMP.. however, you will still have a non conductive path in that corner.
                Please realize while I paint things very black and white.. far and away things are NOT B&W.. but to aid in showing HOW these things work its easier to present them as B&W.
                Yes Rod, I HAVE spent the better part of a lifetime studying this line of stuff!.. and most of it is innate/intuitive to me. I realize it isn’t to many others.. so I have taken a lot of time trying to help others understand it for their betterment.

                Reply to this comment
                • Jack January 18, 00:34

                  When I listed for example how factors work for capacitive coupling, my thinking was the level of attenuation there would be. I look at this and see it but to most it means nothing.. So for the first point.. the amount of capacitive coupling is pretty low. I think the very fact that there would be very little difference in potential along the surface of the faraday cage leaves very little difference in potential between any given points of coupling.
                  To verify this you will need to understand Ohms Law.. and calculate your capacitive reactance… to give you a value of impedance in ohms.
                  To lay folk, if a bird lands on a high voltage wire.. WHY does it not get electrocuted? Electricity only flows between a difference in potential (voltage). The voltage on the bird is there.. but it cant go anywhere so there is no current flow. Current flow is what you feel, what damages and kills.. We measure this energy in WATTS (generally).. and watts is VOLTAGE times CURRENT.. 13,800 volts times ZERO current = zero watts. The bird gets nothing.. that is, nothing he can feel. His feet are on two different points on the hot wire.. technically, there is a very slight difference in voltage at any given point in the wire..(depending on the current flow IN the wire).. but, if there is even one one-thousandth of a volt drop between the two points.. there is probably about 50,000 ohms or more body resistance from one foot to the other. His current would be 0.001volt/50,000 ohms…. this is only .02 micro amps (0.00000002 amps). Multiply this times the voltage ACROSS the bird (0.001 volt) .. and you can see the bird would feel FAR less than one millionth of a watt. He wont even notice. This is largely to point out the level of power between two points a few inches apart on a very conductive surface… first of all. So if you couple (such as capacitively).. your radio or whatever.. from two points not far apart.. its not unlike the birds feet on the same wire.. not much voltage between the two of them. IF you use NO cardboard, plastic, ilk,.. to insulate from the faraday cage walls.. then the higher current going thru the faraday cage walls.. ALSO flows thru the chassis of your radio, bring the currents INSIDE that which you wish to protect. The cardboard creates a high impedance.. MANY ohms.. to GREATLY decrease any of those currents that would otherwise flow in the chassis. Please understand there are TWO currents you are addressing here.. currents in the faraday cage that you do NOT want flowing in the chassis of your protected device.. and currents that are potentially COUPLED by inductance or capacitance.
                  Your capacitive reactance is (can I write this?)
                  X= 1/2piFC.
                  X is the capacitive reactance in ohms;
                  pi is 3.1415926..
                  F is Frequency in Hz
                  C is capacitance in Farads.

                  Hmm.. FYI. Michael Faraday.. did a lot of work in capacitance, radio waves, etc.. and Faraday cages!

                  To calculate IMPEDANCE.. this will be the.. oh god.. Pathragriem theorem.. (Im sure I slaughtered the spelling!).. but the impedance is the square root of the sum of the squares of the DC resistance and the reactance. I don’t know how to express it on this key board.
                  Anyway folks, these will give you an idea as to how tiny of current would be capacitively coupled to your contents. Thicker is always better. Cardboard is one of the better to line with.
                  A note on frequency.. as an EMP is a pulse, it will have many frequencies.. The higher the frequencies, the smaller the signal will be on an EMP E1 pulse.
                  This is about as far as I can reasonable explain in this format. For those who want to take the time.. there are MANY books you can read.. I favor one of the ARRL handbooks! They take you directly thru some basic electronics and have many beneficial things for calculating coils for inductive values for antenna loads .. and tons of other stuff!!!
                  ARRL= Amateur Radio Relay League.
                  Ohms law..
                  Volts/amps= resistance
                  Volts/resistance= amps
                  Amps x resistance =volts.
                  Amps x volts = watts.

                  Reply to this comment
        • Jack January 16, 07:48

          For the reason your gun safe… and even a gang box.. will NOT provide EMP protection.. understand HOW a faraday cage works.. Iv explained this repeatedly in different threads, even this one. RayD has written some on skin effect.. and Iv explained it in detail. In short, the magnetic field from the offending EMP travels across the conductive box. Magnetic fields create currents that travel at right angles to the magnetic field and the currents create magnetic fields that are at right angles to the currents. (did I say that right?). Its important to understand this because when your doors on your metal boxes do not conduct well ALL ALONG THE PLACE THEY MEET.. currents are diverted towards where they CAN go.
          When the currents CAN travel the way they were induced the magnetic fields OPPOSE the EMP field.. but when the currents MUST change directions because the lid conducts only on the corners (for instance), the current changes direction.. and the magnetic field also changes direction and no longer opposes the source field. This makes for a weak spot.. what you might call a point of entry.
          Without this skin effect radio energy can be passed thru the box. Perhaps with attenuation.. but the only way to know how much attenuation would take testing.
          Shielding.. How to cancel out shielding… as an example. When you put wires inside a metal conduit.. you NEVER ground both ends. Grounding completes a circuit so if, say, an EMP were to pass over a conduit with protected wires inside.. the voltages generated can travel down the conduit to the grounded end.. thru the ground wiring.. back up to the OTHER end of the grounded conduit.. and back to point of origin. This cannot happen IF only one end of the conduit is grounded… When that current flows in the conduit it creates a magnetic field .. and that field will create currents in the wires supposedly protected. So, the EMP is transferred INTO the “protected” wires by grounding both ends of the shielding. In this same way, if care is not taken, EMP can be passed thru.
          Confused? I hope all followed.. this would be inductive coupling.. Capacitive coupling later!

          Reply to this comment
          • Silver Rabbit December 22, 12:16

            Jack has done a very good analysis of the problem, thank you. My comment is on the sealing around the openings. I’ve seen aluminum duct tape, steel wool & aluminum foil advocated. Steel wool is great only if both pieces of metal are bare metal. Duct tape has a sticky side. Aluminum foil has a shiny side & a dull side. Copper foil tape also has a sticky side. Try taking a strip of regular kitchen foil, cut it into 2 pieces & overlap the ends. Connect an ohm meter to the two ends & press down on the overlap. You’ll find that the dull side is an electrical insulator. Same problem with the foil tapes-the glue blocks the current flow. Kitchen foil will work only when the shiny sides are making contact.

            Reply to this comment
        • Beaner July 17, 16:37

          I think it’s a crap shoot on the EMP. Either your going to be OK, or you won’t. But, it sure would be nice to get ACCURATE, CORRECT INFORMATION!!! My head is dizzy from all the contradictions…. Like Jack said educate yourself!!!

          I have two types of cooking sources that Don’t need electricity and a solar stove. I also have candles that last 10-12 hours, a lot of salt, sugar, crisco, etc. On top of the rice, beans, pasta… Don’t forget about all the other things like nail clippers, scissors, wind up clock, wind up watch….

          I can go on forever, but for me, I very much want to protect my solar energy investments, however, I can live happily WITHOUT any of the electronics available right now, including solar power. If you have enough water put away, you can perpetually generate electricity with a water source independent of a stream, or river. I know. I have done it. It works excellent.

          So, be smart!!! Have a back up to your back up and please, learn and educate yourself about living totally without electronics. If any kind.

          Reply to this comment
  31. uncle December 18, 03:04

    Are candy tins, cookie tins insulated with cardboard good protection? I would like to have my pen drives, cards, pocket battery devices like USB charger for phone, tablet or LED lamp available daily however protected. I know a phone is useless after an emp but the charger is still good for LED lights and charging handheld radios. until its dead in a few Years. I am seeing technology will be good for a short period of time in a long long time out of the electrical grid. candles and kerosene need to be looked into.

    Reply to this comment
  32. Johnny D December 18, 05:13

    Hey Uncle,
    I think that is a pretty good idea. To be safe, I would suggest using aluminum tape around the edges of the cookie tin (you can re-use it a few times). Also with small items like that, if you could get a few ESD bags, that would provide a significant amount of isolation (be sure to coat the inside of the tin with an insulator (thin cardboard, to keep the outside of the ESD bag from making contact with the inside of the tin). Don’t forget the inside top of the tin should be insulated too. I like the idea for LED flashlights and maybe rechargeable batteries and charger.

    Reply to this comment
  33. uncle December 22, 00:00

    As I learn I hope I too can assist others. SO! 🙂 I have lined the the metal box with cardboard non metallic duct tape to hold the seams. I have int he back of mind all your guys words [Antenna]. that the EMP would stay on the outside, your goods safe inside.

    This box has a folding hinge to keep it open. two blades on the lid that would catch a lock to secure the box to the locks. With Antenna in my mind. will these features bring the EMP into the box? We purchased the ridgid 32R-OS to store our items. homedepot this should give you visual of what I am speaking of. I have covered these items in NON metallic duct tape. will this suffice or should I cut them off?

    Reply to this comment
    • Rod December 28, 19:44

      Sorry to be late in replying but life has kept me busy! I would use Aluminum duct around any making surfaces, but the Rigid box should be OK otherwise. Sounds like you are on the right track!

      Reply to this comment
  34. uncle January 2, 00:50

    Happy New Year all

    EMP BAGS which bag did you finally choose which company has the best price?

    Reply to this comment
  35. CDR Sam April 25, 18:15

    You mention the inverter of a solar power system being susceptible to an EMP, but wouldn’t that also apply to the controller?

    Reply to this comment
  36. Kirk April 25, 19:57

    The Canna Bay Faraday cage provides up to 2X the attenuation protection of the , so called, “EMP bags” and cost just $75 for 20+ liters of storage.

    Reply to this comment
    • Uncle November 4, 07:14

      I like the idea but would rather purcahse a drum shape than a bucket.

      Reply to this comment
    • Jack January 16, 09:00

      Please be aware that if you get 2X the attenuation, this is only 3db. Not a lot if you are looking for about 50+db.
      On those cookie tins and popcorn tins… place your cell phone inside on a piece of paper if you have any conductive surfaces on your cell phone .. so you insulate it from the metal of the can.. Seal it in.. then have someone call it while you stand by listening. Our cell phones takes about the third ring on the calling phone before the called phone will ring once.. so don’t give up to early!
      If you hear it ring inside.. Id scrap the idea of using the tin, at least, by itself.
      These tins usually have conductive mating surfaces.. but no telling what is in the bottom where its mated to the cylinder.. or where the cylinder comes together. Cans used for canned foods at the store for instance.. their lids have a rubber gasket of sorts (mostly painted on the edge before they are rolled to their pre seal configuration. so full conductivity thru this area maybe lacking.
      In prepping I have had the opportunity.. for our group.. to go to the local LDS cannery where we would can thousands of cans of beans, rice, oats, .. you name it (if they had it).. for our group (filling every ones individual orders.. but as a group). This is no longer available as of a few years back… however I did look into how we could continue.. but our focus was the #10 cans, and getting them to Alaska was overtly expensive. But I made a study of how I could put together a can sealer.. and maybe reuse cans!
      Lastly, I do not know what you could possibly be calling an EMP bag.. but I would certainly test it before placing ANY dependency on them! Mylar baggies can deflect static.. but in my best judgment.. would do little for EMP protection!

      Reply to this comment
      • Kirk January 16, 12:20

        Yes, the Canna Bay cages are lined with an antistatic plastic liner. “EMP bags” are the antistatic mylar you mention. They’re practically useless.

        Reply to this comment
  37. uncle June 10, 20:21

    I can only imagining that I am not the only one totally frustrated about the lack of solid collaboration . on effective ways to protect your electronics. I have been reading since since DEC 17. I walk away from the computer more confused that when I first sat down. :)’ Now I read you should follow a method called ” use and scoot” after a first EMP. My assumption is to open your stuff use it then reseal before a secondary strike… WHY?

    We purchased a construction box. to put electronics in we lined it with cardboard. We purchased EMP bags to also put the stuff in. we purchase ammo cans and have used copper tape to seal all of the above. . I read the paint should be removed for the copper tape to work. ( I get the basics of that for an electrical connection). Why sand, a seal is a seal how would a “wave” get though a copper taped bond?

    Reply to this comment
  38. Barbara August 12, 19:48

    I have been reading your news reports for about 3yrs now. I’m a widow nad own a above ground doublewide. Is it EMP proof. or what can I do to make it so. I also bought a cargo steel container a few mo. ago and its on a cement pad. I need to stay here because I raise chickens. I’m 70yrs old.

    Reply to this comment
  39. Vance November 4, 01:51

    Can the internet come through a Faraday cage? Can you use a computer inside of one?

    Reply to this comment
    • Uncle November 4, 07:26

      I know little of this subject and still trying to learn.
      What i do understand, fraday cages are designed to stop radio waves signals. so your computer would not receive a wireless routers signal. FI you are using Ethernet cables .then your computer would be made useless as the electric waves would go through cat 5 /6 wires and fry your computer. if yo have your computer plugged into an outlet the same thing. by bye (name your operating system goodbye) and all the little parts on the circuit board. a Faraday is a sealed tight barrier to protect from radio and elect waves. Unless you can afford a military designed room to protect your stuff and still be in contact with the outside world.
      Almost all of the stuff I have mentioned I read through all the comments above. give them a good go over.

      Reply to this comment
  40. Sri November 7, 17:07

    Am currently pregnant. Can I still continue working inside a Faraday cage , we have 2G and 3G signals emitted inside it.

    Reply to this comment
    • Rod November 8, 14:59

      Yes you can. The radiation from those sources is neither ionizing nor large enough to cause problems.

      Reply to this comment
  41. Kirk0708 December 16, 03:24

    After a few years of research and testing, I’ve found that one of the best “naturally occurring” Faraday Cage is those popcorn tins they sell at Walmart. Practically impervious to RF once sealed.

    Reply to this comment
  42. Jack January 17, 04:18

    Since all of you are fellow preppers I wanted to suggest some reading materials .. some of them are directly related to EMP.. and some have sections on EMP.. some are homesteading/off grid info.. but they are some of the best Iv come across. This is very limited.. many of my own are to do with cold weather survival as I live in the “northern most frontier”..
    As Iv mentioned earlier, Im an Extra Class ham with decades of experience with radio waves and radio electronics.. not that I know it all but I do have extensive understanding of radio waves.. and EMP is basically a radio wave.
    One of my books that might be helpful (especially for engineers).. is “EMP protection for emergency operating centers” United States, Defense Civil Preparedness Agency.
    Another book I HIGHLY recommend has to do with nuclear war survival. Many people say they want to be at ground zero and not survive a nuclear war.. trouble with that is if you are not. Sticking your head in the sand will not only not make it go away.. but the relatively simple procedures that would save you.. you wont know so you will suffer the very death you fear most.
    I would suggest checking out KI4U website.. I also suggest getting a copy of “Life Saving Nuclear Facts and Self-Help Instructions.. NUCLEAR WAR SURVIVAL SKILLS”.. by Cresson H. Kearny.
    What people do not know.. the worst of radiation deteriorates rather quickly.. This book can be downloaded free at https://www.oism.org/nwss/ I would recommend BUYING the book on Amazon.. but you can certainly review it online. It covers a great deal.
    Another book I suggest.. not that Im a Mormon but they are the MASTERS at prepping. But that would be THEIR own prepping book.. I will have to look it up.. I have copies of it in 2011 and 2013 or so.. Much the same.. but they offer a great deal.
    Planning and building designs.. “The New Pioneer’s Handbook”.. they approach everything scientifically… calculating calories of food for what you will need per person/per day sort of thing.. They also show you how to calculate your energy losses for your home.. how to calculate heater size for a cabin.. that sort of thing. Iv absorbed much of it but haven’t memorized all these things..
    Cheese making.. if you like cheese’s.. is Rickki Carrolls “Home Cheese Making”..
    Please folks, I do not get a single penny for recommending these books.. I gain ONLY that others are more prepared, survive.. I believe the better people are prepared.. the less people will be trying to burn me out to steal what I have.. and the better we are as a nation, to rebuild.
    A VERY good book to read .. to get a much clearer concept of how things might be if we should have an EMP that is anywhere near as bad as many think it would be.. is “One Second After”. It tells in story form, of the things that might well happen.. and the things that follow.. The story is fictitious .. but the places are not.. and the sequence of events are not just possible.. but probable. Its a good read as well..
    Another good read is “The Patriot”. its written by James Rawls, the guy at the helm of “survivalblog.com”, one of my highly esteemed sites.
    One of the things I strongly encourage.. (I should put this under the guns section!).. is if you are choosing a weapon for TEOTWAWKI .. or any situation where you are defending your place..possibly as a group of people.. you want to have COMMON AMMUNITION… but not only common ammunition but common magazines at minimum. Imagine the chaos if you were in a war.. and everyone shot a different ammo?.. Or, you run out of ammo in a shoot out.. and I through you a magazine of the same ammo.. but different clip. YOU will have to unload the magazine and reload it into yours.. WHILE PEOPLE ARE SHOOTING AT YOU. Not a good idea.
    Now I know this will be WAY out there for many of you.. but it COULD all happen! Personally, my concept is to have it and not need it .. then need it and NOT have it… cause then you die.. and your family.. and all the stuff you worked to be prepared for.. is now someone elses.
    I have made the decision to go with 5.56mm (.223).. because the round is small, light.. and one can pack a good deal of ammo in a small space. Another reason.. many sources of ammo will dry up. Powder will be hard to find.. as will primers, projectiles.. This round is not only very common but its a military round as well and has a much better chance of being around for that reason.
    308 would be a second choice, although it is larger, heavier and gear for it is heavier. For me in Alaska I would probably want at least something suitable for large game…In the lower 48, while 223 is not legal for big game in most states, a decent shot will drop a deer. if you are lucky enough to find under dire circumstances.
    Books on identifying wild plants.. knowing those that are toxic/poisonous.. Mine will be different from yours!
    Anyway, these are just some good backbone books I think you will find invaluable!
    Best to ALL of you out there!

    Reply to this comment
  43. Flyboy February 19, 01:55

    Could you spray the inside of a metal garbage can with “Flex Seal Spray” (it’s a sort of rubberized material that you can paint on surfaces or spray it on from aerosols spray cans). Could that be used as a substitute for cardboard, as it takes up less space in can, covers better, and is easier to work with than cardboard.

    Reply to this comment
  44. Flyboy February 19, 02:22

    Does just burying a leak proof container underground solve the EMP problem? And if burying a leak proof storage container, how deep would it have to be buried to be fullroof from EMP? And would that also work for a large underground bunker, that us, would everything in the “bunker” be EMP proof?

    Reply to this comment
    • Jack February 19, 03:28

      When I said “Yes, it would work” please note this was regarding a spray on material inside the faraday cage. As for burying, no matter how deep you bury a box, it will not be a faraday cage. Burying in a box will employ the dirt as a means of attenuating the EMP.. but whether it will stop EMP..?? You would have to tell me how big the EMP source was, how high, where you are in respect to where the blast was.. how deep, if there were mountains blocking direct view of the blast point.. what kind of box, how it was built.. there are endless questions I would need to know.. and if I had them I don’t know anyone who could actually put it all together for an accurate answer.
      Make or obtain a suitable faraday cage/box. Protect the inside as we talked about already.. (Iv written on this in this and other pages of this site, regarding EMP).. Put your survival electronics inside it.. MAKE A LIST of every item inside it, ESPECIALLY if you bury it- you will forget what’s in it.. and what is NOT.. Put a copy on the inside top, and save one for your paper files. Then bury it if you so desire.
      DO realize it may well be likely that if you have to get it you may well have very little time. You might consider burying it in a “go to” place where no one will find it but you.
      I believe that most cell towers.. and most satellites.. will be killed in an EMP. I would not depend on GPS for navigation. These work on cell towers and/or satellites. Buy a GOOD compass and maps.. learn to use them. If you have room, THEN add a GPS, cell phone. HINT, remove ALL batteries and if you must keep them with equipment, put them into a heavy duty plastic bag at minimum. If you don’t live in non-freezing climates, they maybe damaged from freezing .. and they may leak. The baggie will protect from battery chemicals from destroying other items.
      Remember, you only need faraday cage for ELECTRONICS kind of stuff. Some lithium type batteries have electronics circuits. If you battery has a low voltage cut-off and or charge protection (again, LITHIUM types).. they have electronics inside, need protection as well.
      When you get all your stuff together, carefully look over for all your accessories.. and don’t forget your wall-warts/chargers! These are almost always full of electronics.
      Mechanical stuff-guns, ammo, anything non-electronic.. does not need to be in a faraday cage.
      Electrical items;
      I have a 8-10kW diesel generator.. Im still working on electrical attenuators for protecting my generator and my inverter… but for now, I carry extra diodes for the control circuits. (I cant find really large toroid cores to wind as common noise attenuators. I may have to develop and cast my own powdered iron cores. Common noise winding causes the inductive impedance to cancel on the power frequencies.. but NOT on the “noise” [EMP]). The inverter is simply pretty vulnerable. Building a faraday cage for it, protecting (EMP attenuation) on the input and output leads.. and buying commercial EMP protectors is about all I know I can do.
      This is beyond your question but hope it helps someone!

      Reply to this comment
  45. Jack February 19, 02:34

    Yes, such would work.. JUST BE SURE IT DOES NOT SCRATCH OFF so that your contacts do not make conductive contact with the cage.
    Secondly, THICKER material is desirable. While inter capacitance is not as critical as current (from an EMP).. cannot go THRU the frame of the “protected item”, minimal inter capacitance would be desirable.
    While the ticker the better, there are so many variables to deal with! If you built it to an 1/8″ thick I cant imagine that being inadequate. And Im probably over stressing it. However, I think of things this way: if its important enough to select it as an item essential to my post EMP survival.. Id rather overdo it and be OK then to under-do it and find my survival item is now toast.

    The reason I like corrugated cardboard.. is BECAUSE of its thickness.. and cellulose has a rather low capacitance value as well.
    I have a high value on communications, especially POST EMP. I believe it will be absolutely essential to recovery, protection.
    I see many who want to thru in a cell phone. I cant tell you enough what a waste of time and space this is likely to be. If our phone companies will EMP harden their towers, it would be totally reversed… To my knowledge about the only thing EMP hardened is military communications and the highest grade is strategic stuff.. communications from coast to coast, etc.. to the least hardened, inter communications at local levels.. like between troops..
    I have a couple of high end ham radios I have.. complete with digital systems, computer, printer.. all 12vdc directly 12vdc operable.. I keep in a couple of faraday cages for this reason.
    This is well beyond your question, however I wanted to give an example of what Iv done and why.
    Besides, if no one else has a ham radio after an EMP.. what good is it?
    Blessings to all!

    Reply to this comment
  46. steve September 30, 02:02

    In regards to making a Faraday around a bed to protect from emfr exposure, do you think its necessary and if so when the bed is protected does it have to be a complete seal or else you would be exposed to the radiation in a worse kind of way. Lastly, if there would not be a complete seal which is likely then would grounding the bed prevent unusual exposures to emfr? The reason I ask is I’ve seen some articles talking about reflection and if I understand that correctly that means if you don’t make a protective barrier correctly you might wind up worse than previously. Much thanks for help!

    Reply to this comment
    • Rod September 30, 02:38

      Steve, I am not sure why you would want to put a Faraday Cage around a bed, and you mention EMFR. An EMP pulse, or series of pulses, will not harm a human being. Now, if they were continuous for a length of time, such as standing in front of a microwave antenna, that can definitely cause problems. If you are talking about EMFR as being normal broadcasting RF (100KHz up into the microwave spectrum) then it is unlikely you would be exposed to enough RF in a normal habitation situation to worry about. I have worked around higher power radio and TV transmitters for the last few decades with no ill effects. I think we would need more information as to your exact situation as well as your exact concerns to be able to give you good advice.

      Reply to this comment
  47. fuzzy1949 October 29, 17:41

    You need to rethink some of your answers. For example, #3. Will a cll phone work if it’s been in a faraday cage? Consider this, cell towers are required for any signal to be transmitted. Cell towers are not housed in faraday cages and as such will not work after an EMP.

    Reply to this comment
  48. left coast chuck October 29, 18:06

    This post is a good example of someone posting on the internet and the reader has no clue as to the bona fides of the person writing the article. We have this article by a person who uses the name “Diane”. We may assume that the person is a female but anyone can use any pen name they choose, such as “left coast chuck.”

    We also have no clue as to the qualification of the author to write the article. Has she done individual research so that she can authoritatively state the posits she presents?

    Or is she just regurgitating some information by some other unknown author who posted an article on line?

    At least some of the response writers have stated their qualifications to answer some of the questions, ie., worked as an electronics technician in the navy, work as a service technician for an electronics company. That allows the reader to judge for themselves whether the opinion expressed is valid or not; whether the person stating the opinion has the technical background to post a valid opinion.

    I have in the past urged readers of this list to always consider the qualifications of the author of these articles. We have some who post authoritatively yet we have not a clue as to their qualifications to post such authoritative articles.

    Reader beware!

    Reply to this comment
  49. left coast chuck October 29, 18:24

    I would like to comment on the author’s response to the flashlight question.

    First, understand I am not an E.E.; don’t have a degree in physics, mathematics or any other associated field that might have a bearing on the topic.

    However, I have considered the problem of flashlights and in light of what I know about both CMEs and EMPs which, I will admit is not heavily technical, or if it was, it was so technical it might as well have been written in Greek.

    That said, there are basically two types of flashlights. The old kind we used as kids to read books under the covers at night and the newer led lights that have varying levels of intensity and can send SOS signals and strobe effect, are hot enough to light your cigarette and can blind a bad guy if he doesn’t have his welding glasses on.

    With regard to the first, the old fashioned Maglight with it six or eight D size or C size batteries, an incandescent bulb with a spare bulb in the battery compartment cap. my conclusion is that with no electronic circuitry other than conducting the electricity from the batteries to the bulb, if the light is off at the instant the pulse, from whatever source arrives, the flashlight will most likely still work.

    On the other hand, if you have one of those multi-function led lights, if it isn’t in a Faraday cage, it had better have those points on the lens so that you can use it as a club because it probably won’t work. The circuits that allow the switching of intensity and function will most likely be fried.

    With regard to the simple led light that only has an on and off switch, I just don’t have a clue. It is my understanding that l.e.d.s have some circuitry in them. If that is true, how sensitive that circuitry is to electronic overload is a question for which I have been unable to find an answer.

    If my understanding about circuitry in the led itself is correct, then it might be fried. If there is no such circuitry, then it might not be fried.

    So my answer to the simple single led light is : Duhhh, I donno. Sorry, but unlike some, I am not the font of all knowledge and try not to sound like I am.

    I might add the responses to this post are so numerous I have not yet had time to read through all of them so the answer to this post might lie within one of the other posts.

    Reply to this comment
  50. Auge October 29, 18:58

    tell me where I can get rolls of toilet paper like you showed
    in your article, I could buy loads of them and sell them
    as I needed money. That would help me out a lot Claude
    and don’t tell me you are just kidding, I may have to get
    even so this is the second time, good for me

    Reply to this comment
  51. red October 30, 21:01

    Like this! niio

    Reply to this comment
    • Guy December 14, 08:35

      First let me apologize for anyone offended, but the amount of parroted misinformation is utterly laughable here. So many here claiming to have Electrical Engineering PhD’s, etc…just stop. That being said here goes:

      Faraday cages DO NOT NEED TO BE GROUNDED.

      Burying your items underground will not protect them.

      Starfish Prime isn’t a great end all be all example of what CAN happen during a Nuclear EMP…research the Soviet K-Project.

      A Nuclear detonation induced E1 is LINE OF SIGHT

      Here is some of the laughable myths people parrot:

      A small cardboard box wrapped in aluminum foil will protect your electronics…if your electronics can fit in a small box they are not a large enough of an antenna to be damaged.

      Placing a cellphone or radio inside your shoebox faraday cage and seeing if it works is a good way to test if it would work in an EMP…I am shocked to see this advocated, ANYWHERE. An outbound adio or cellphone signal is vastly different from the energy produced from an EMP, there are better more logical ways to test your faraday cage’s efficacy this is like comparing “apples to purple”.

      An aluminum garbage can with cardboard in it will protect your equipment…first off, whatever you had in the can was smaller and less likely to act as an antenna, but now you have made a larger antenna; An E1 HEMP has been shown to initiate an arc over an insulator,
      Given the current involved how well do you think your trashcan and cardboard will hold up?

      Make sure to store your AA batteries in your faraday cage…your batteries WILL NOT BE DAMAGED BY AN HEMP…certainly not anymore that your box wrapped in tinfoil will protect them.

      A “Blank made of/wrapped in aluminum” will protect against an EMP…Let’s just say your shoebox covered in aluminum foil was a sufficient antenna, do you know what happens when you apply current across varying thicknesses of a conductor? Resistance, Heat, bad things. Because your conductive material was not uniform there was resistance, which created heat, a lot of it, which melted your foil. (In Kazakhstan underground powerlines melted because of this).

      Keep spare car computers, EEG’s etc so your car wont be permanently disabled..the EMP commission tested 37 cars and 18 trucks of varying years and models. Out of the 55 tested 1 was disabled. While a number experienced dashlight issues, or the engines stopped, all were able to be restarted BUT ONE. And these were running cars, cars that were not running had ZERO negative effects.

      A Faraday Cage must be totally sealed tight no gaps whatsoever!!!!…well now you don’t have a Faraday Cage, you have a Faraday Shield. You need to have gaps smaller than the wavelength you wish to shield.

      A Solar Flare could totally take out my laptop…Geomagnetic Storms do not produce ground level E1 or E2, your porn is safe.

      Stop reading the BS articles and comments on prepper boards, read articles on science based boards. There are better ways to test your Faraday Shield than using a radio (Hell hitting it with a stun gun would be more apropos).

      I am in no way knocking the prepper lifestyle, I consider myself to be quite prepared. I’m not riding around on an ATV wearing camo running gas mask drills, i do however:
      -Have 20 years worth of food for my family
      -Plenty of stored water and an RO system
      -A concrete home with a basement shelter that provides 1000+ gamma radiation halving thicknesses
      -Enough firewood and trees on my land for all the fire I need
      -Medical training of my own and a wife who is a practicing Nurse Practitioner.
      -Antibiotics and medical supllies

      My advice, worry about the things I listed above, not whether or not your cardboard lined ammobox is perfectly sealed.

      Reply to this comment
  52. Jack December 15, 05:33

    First, Id like to say Thanks for your article, Guy. Certainly I wonder about YOUR background!
    Iv seen some who claim they have a PhD talk of EMP.. but what field do they have that PhD in?! Someone with an EE I tend to consider as not being clueless.. but an EE doesn’t mean they are know all to beat all.. Iv got decades of experience with radio, but not just radio but private study on radio wave theory.. wave forms, etc.
    I would agree with all you said but there was some things that you said that concern me, if you might be simplifying or if you dont understand.
    First, RESISTANCE is the opposition of current flow. Greater resistance = greater heat. Enough heat may well melt aluminum or other low melting metals. Best electrical conductors seem to follow best heat dissipation. Copper, Aluminum, etc. Places where conductive material is thinner WILL have higher resistance. These spots WILL see more heat. But I dont see heat and melting being the big issue.. considering the length of an E! pulse. If it tried to melt it would be over before there would be time for metal to move. And if it did, how far can it melt and move in.. a NANOSECOND.. before the heat source is gone?
    Never the less, what you said about testing of gear with radios, cell phones only served to see if it can protect the item against that frequency at that level of power level. I dont even believe most of the test equipment used has the level of power needed to really TEST the faraday cage, shield, whatever you want to call it. Not that I would consider these aluminum boxes to be remotely adequate shielding. I have equipment in adapted ammo cans.. but I consider them as inadequate thickness. But, as I have nothing (yet) to replace them, they are better then nothing.
    Completely sealing is kind of… “how much protection do you desire?” kind of thing. An E1 pulse .. (“Pulse” defines the waveform.. I mean, a pulse is a combination of frequencies in a short time. One might look up the definition of a square wave or sawtooth wave.. its a combination of frequencies. But, these waveforms are continuous. Never the less, an E1 is similar to the first half cycle of a square wave. Many wont follow this but can I assume you do?
    Breaks in a faraday box (shield, whatever).. is based on counter magnetic field that is generated by the very source you are protecting against. Breaks in conductive path means the generated currents will flow around these gaps. Change in direction means the counter magnetic field will leave weaker or no protection in that spot. My concern with thin material is magnetic saturation.. which could mean inadequate strength to defect the EMP. For those who dont understand, take a powerful magnet, place it on a piece of thick steel. It will be difficult to remove. Now, place it on a very thin piece of sheet steel. It will be MUCH easier to remove. This is because the thinner steel does not have enough metal to carry all those magnetic lines of force to lock onto the thin steel.. like it does in heavier steel. Some magnets will show this better than others. This is a demo of saturation.
    Wavelengths; in free space (vacuum), radio waves travel as 300 million meters per second. And anytime you have electrons traveling, they generate a magnetic field.. I envision it like a wake from a boat traveling across water…(you can apply this to Compton electrons as well. These are electrons stripped out of their orbit from a nuclear blast.. an EMP). When you transmit.. your electrical signal travels back and forth on the conductor (antenna). They generate a negative wave when they travel one way, and a Positive wave when they reverse direction. Then they reverse again.. etc, back and forth. How far does the negative wave travel before the source electric signal reverses? and once it reverses back to the same point in its cycling.. means you have a negative field traveling at the speed of light.. then a positive field following it, then a negative.. Taking any point .. and the distance between it and the next identical point in the same polarity.. ONE cycle.. this is the wavelength of the frequency you are feeding the antenna. If you take and divide 300M divided by 146MHz (middle of the 2 meter band, you get almost exactly 2. This is why its called “2”meter band . This is 300 million meters divided by 146 million cycles per second (Hertz.. or Hz). The millions cancel.
    Guy, I expect you already understand this.. this is for any who dont.
    As for arcing thru.. there needs to be a difference in potential to drive electricity. Like water, you need to generate a difference or it isn’t going to flow. I will say if you take my TIG torch and try to strike an arc on ungrounded metal.. it will give a blue hue in the air around the tungsten. This is the high frequency/high voltage just ionizing the air around it. I would not consider it current flow. This COULD “arc thru” and start a fire in cardboard.. IF it was long enough time frame. BUT, it would not be anything of a current. I would support the use of cardboard to maintain isolation from the metal shield/box/whatever.
    You need to remember, trying to explain a great deal of this stuff is NOT feasible to layman, certainly on a written format like this. Details need to be generalized, quantified. Personally, I would be VERY happy to teach this stuff.. but most people just want “the bottom line” (I have taught it in small groups.. and that was ALWAYS what I got from lay people).
    I have not covered the range of frequencies of an E!.. but in general, the higher you go in frequency, the weaker the E1 gets. Yes, higher frequencies are certainly line of sight. This is not quite that simple. You also have a LOT of bouncing around, especially in cities (other wise cell phone coverage would be almost nill in towns). Lower frequencies tend to be “ground waves”. They travel around things. Look at sub woofers. Sound, which is far slower velocity traveling.. will use mid to tweeter speakers, being more “line of sight”. A single woofer can be placed as a common, in the middle of the tweeters.. and it sounds great. Used to be each speaker was full range. The lower sound waves of the woofer can, do, travel across and thru media. NOT so with those tweeters. Yes, the lower EMP wave frequencies will follow the earth much more so than higher frequencies of E1.
    OK. my wife is growing tired of waiting to eat her.. our.. dinner!
    Please understand, Guy, I really like your response.. but there is some things that are not exactly considering certain elements. If you go back and read my comments .. Im trying to say much the same as you are and you actually vindicate almost all Iv said in the past.
    To be fair, there are two types of signals generated by an antenna broadcasting a radio signal. My observation is lower frequencies tend to run more of an electromagnetic field.. Higher frequencies tend to run more on electrostatic fields. There is other theories, electrostatic, for faraday cages/boxes/shield/whatever. I think its easier to explain electromagnet fields to people. Something they can grasp easier.
    FYI, my background is multiple but extensive in radio, electronics.. and Iv been involved in radio theory, waves, for over 50 years. Iv done extensive private studies in many fields, including atoms and behavior.. and wish I would have studied into physics early on. But, I still haven’t made up my mind what I want to do for a living! LOL!!! (retired.. mostly.. as commercial/industrial electrician).

    Reply to this comment
    • joe February 1, 04:33

      I agree with everything you said, except that the EMP heating effect is nill. The way the EMP effect was discovered was that the shielding on the electronic cables was melted, Thiis was on the atomic bomb tests, So belive that foil and other thin material will melt and or fuse. The main thing that you can do is place all electronics that have any diodes, transistors, integrated circuits in a very good faraday cage if you want them to be usable later. As far as radios go, get or make the old vacuum tube radios, they are not affected except during the pulse itself. .
      I worked with the military on shielding their equipment from EMP events.

      Reply to this comment
  53. modrare January 31, 20:21

    I have a standard 17KW Generac whole-house generator. Is there any way I can protect it against an EMP?

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    • Rod February 1, 00:36

      Anything that is connected to an unprotected source, such as power or control wiring, cannot be shielded by any practical means. To be protected the entire generator must be shielded with absolutely no connections to the outside world. The same goes for radios or any other electrical/electronic equipment. I am very familiar with protected items like those mentioned above and they are not connected to the outside world at all.

      Reply to this comment
    • Jack February 1, 05:45

      HOW BADLY do you want to have your stuff protected?
      My suggestion would be to put the generator in a Faraday cage first. I have several write ups on Faraday cages on this site and I might suggest going back and reviewing them to understand what a Faraday cage is, how it works. There is a couple others people Iv found on this site that understand it, but there are many who dont.
      IF you live in or near a significant military installation you might be at a higher risk of EMP damage. Many factors will determine your risk; the proximity of the blast, the strength of it, the location of it.. do you live in the mountains or on flat land for miles.
      One consistantly factor is how you are connected to the grid
      Generator plants of all kinds, generate a very high voltage. They do this for lower energy losses.. and so they dont need to run larger conductors… but these voltages.. wires.. are not suitable for residential distribution. You see these wires on the large poles or towers. They run between generation plants and substations where they are transformed down for distribution at lower, easier voltage to distribute into residential areas. You may see towers or poles with huge insulators and under them might be a cross bar with much smaller insulators. Your distribution voltage will be more like 12,800 volts while your main transmission lines will be 115,000 to 230,000 volts.. and some 500,000 to 750,000 volts.
      These “lower voltages then run along the power poles that you might see along back roads.. where you will see the pots (transformers) hanging on these poles sending 120/240 volts to a home(s).. and in industrial areas you might see 3 pots.. and these typically send 277/480 volts to industrial facilities.
      The main point is these lines act as antenna’s for EMP and might carry the pulse many miles.. and the longer the more voltage it might absorb from an EMP. Here’s the (potential) catch: Transformers tend to isolate one set of wires to the next. So, there is potential to limit an EMP from gathering ALL and sending it into your home. There is MANY varibles in not only this but pretty much ALL things EMP.
      In most cases Id be a little more worried about the EMP the wiring in your house picks up and then sent down to your appliances.. and into your generator that is connected.
      Your best bet is to NOT have your generator connected and leave the generator in its Faraday cage.
      The only real reason to have your generator connected to your system is because you have an ATS (Automatic Transfer Switch). Hospitals have pretty much instant transfer.. buy using a UPS system that allows time for their generator to start and stablize.. then the switching goes from UPS to generator.. pretty much seamlessly. Most residential transfer switches are MANUAL… so, Id leave it not connected until needed.
      Now, if you still must have it all set up for automatic operation.. there are companies that make electronic devices for placing across your service that can react instantly (Some, a fraction of a nanosecond to single digit nanoseconds, grounding out that pulse. You need to talk to these people for detailed information. I have not worked with them. But, you really need to be careful about any unit that instantly drops to very low resistance/impedience (a short). While this will send the EMP to ground, it will also do the same with any power on the line! Iv taken this concern to my ham radio lines where I have GDT’s (Gas Discharge Tubes).. but most of these are questionable as to if their speed of reaction is and most manufacturers have suggested using the semiconductor units as they are even faster. These companies typically make units for control wires, communications lines, including phone, cable, and internet lines… and Service conductors as well.. but these devices tend to be expensive. I think it would be improper to make any recommendations of suppliers in this forum.. but you can do a little research. Look up Gas Discharge tubes for starters. that is, AFTER you pursue Faraday cages.
      (Service conductors as those conductors that provide incoming lines from the utility).
      So, it is very possible to protect your generator.
      Im a retired Commercial electrician, background in radio electronics, and extensive research into radio waves, EMP, etc. Im not formally an engineer but have extensive background and moderate experience in working on EMP services for largely Military installations.

      Reply to this comment
  54. Dan February 1, 02:05

    Living in a metal pole building. How about that?

    Reply to this comment
    • Rod February 1, 03:45

      In a word, no.
      For a complete explanation go through the previous posts and this question is thoroughly explained.

      Reply to this comment
  55. joe February 1, 04:10

    I don’t know where the myth came from, but solar cells are simply light diodes and all electronic diodes will be killed by an EMP event including those in your altinator on your car.

    Reply to this comment
    • Jack February 1, 06:53

      OK, Joe.
      Then, WHY will an EMP kill diodes just because they are semiconductors? Think about it.
      I cant say for absolutely sure but I really do not think they will be damaged JUST BECAUSE THEY ARE SEMICONDUCTORS.
      These semiconductor.. diodes.. are all connected together both to each other.. but their output is then connected to wires to run the “gathered” power to your MPPT or whatever you have to feed your batteries or whatever you are doing with the power. An EMP wave crosses over wires.. power wires, phone lines, etc.. inducing voltage onto those wires.. THAT ARE CONNECTED TO YOUR SOLAR PANELS… or your computer, phone, TV or whatever.
      In my experience and talking to EMP engineers the consensus is small radios such as my handheld VHF/UHF radios are likely safe IF you do not have a larger antenna or other wires/cables, they are likely to withstand a substantial EMP. Kinda says a lot doesn’t it?
      Its the “antenna” you connect to them. Protect that wires from feeding the pulse back to them is the first step in protecting them. Not sure what to do about the tabs and how much danger the cells might be in by the necessary interconnections.. or how to protect.
      BTW, I still keep my extra radios (EMP backup) in a Faraday cage, just to be sure!
      Dont be to sure your solar panels are doomed…

      Reply to this comment
      • joe February 2, 04:21

        You are right about the antenna being the problem, show me any solar panel that does not have wire leads or traces from each group of cells to connect them in series or parrel, to provide the voltage output they produce. If you have one that doesn’t then you might be correct, but accourint the the military rules for EMP any thing over a couple mm is enough to induce damaging currents into semiconductors, that is why hardened semiconuctors have blocking diodes across each input and output..

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  56. joe October 24, 02:15

    Do I need to keep my solar panels in a Faraday cage?
    No. The only part of the system you have to worry about is your solar panel inverter. Don’t worry about your solar panels; they will be fine, wrong the solar cells are semiconductor diodes, any connection longer than a millimeter will destroy them.
    13. How do I test an object to see if it will work as a Faraday cage?
    You can test any device that you think might work as a Faraday cage with a radio.
    Wrong, first radio operates at the wrong frequency,, Plus an EMP pulse is millions of times stronger than the signal the radio or cell phone signal. There is no way to test without having at least the proper frequencies, and that includes nano wave, al the way down to ultra-sonic. and in the thousands of volt range for each frequency, any other test is just fooling yourself. .

    Reply to this comment
  57. Jack October 24, 05:59

    OK. Iv stood back… largely because so many as the same questions Iv explained several times already.
    Iv explained how a Faraday cage works from an inductive side.
    All Im trying to do is share what I myself have learned from EMP engineers, and decades of observation of radio theory and building of EMP structures.
    Everything I put out there is stuff I put my life on. I mean, I would fully trust to be accurate. IF Im not 100% I clarify Im not 100%.
    If you read past explanations about Faraday cages, you will know a container is NOT a Faraday cage (as the bottom is made of mostly wood). Yes, it will shield to some level, and it is on the bottom. Much better then being on top of container.
    Joe, I think you missed my point: Yes, HOW can you protect from the tabs on the solar cells?! Might be able to design them to manage EMP safely. I have some ideas.. but most folks will not have the skill needed.. or have the knowledge to understand what they can do when in question.
    You talk of frequencies of an EMP; do you understand how multiple frequencies are generated? Do you understand how a pulse form generates multiple frequencies? Do you understand electrostatic waves and electromagnetic waves?
    There is no possible real way to know how strong an EMP might be.. or the energy level in different frequencies. You can only make educated guesses. Reasoned calculated guesses. The more you know and understand, the better off you will likely do to protect yourself and your gear.
    Many of the things you have said I would either agree with.. or, because they take the worse case footing, would be safer for the lay-people public.
    I do want to clarify to those who dont realize it but “Ultrasonic” is SOUND, not magnetic waves. Frequencies are still frequencies, however. An EMP is a MAGNETIC wave; untrasonic is SOUND (compression waves in air).
    The longer the wire (“antenna”).. the more voltage it will collect. (voltage at resonant frequency would tend to peak disportionately but with one pulse form it MAY not show or show little).
    And if all these considerations.. add Differential- and Common-Noise, factoring in cancellation. I have a 8kW diesel generator.. I plan to add inductive coils in series with the 120/240vac output, which will help absorb RF and effect power frequencies minimally. Core will be of powdered iron but must not be conductive to prevent Eddy current losses.
    By winding the power wires together on ONE core, the fields from the wires carrying the power will nutralize inductive losses to power frequencies (leaving only DC resistance losses).
    This is a demonstartion (in words rather than visual illistration) of Common Noise attenuation.. as there is no reverse field to cancel.. but the power flows thru one wire and its return is directly along side, cancelling the field generated from the first wire. This is demonstrated by a rule called the “left hand rule”. The magnetic field generated on the wire from the electricity going one way is cancelled by the same flow of current now going in the opposite direction, being equal and opposite, cancelling the inductive reactance (AC resistance) it causes. Only an electric current that has no return path will get the effect of the inductance. One is Common and the other is differential.
    The amount of inductive reactance is based on the formula of 2pi x Frequency x inductive value (Henry’s). As you can see the higher the frequency, the higher the inductive reactance. Total impedance is the square root of of the sum of inductive reactance squared.. plus.. the DC resistance squared. Please rememember a 60,000,000 Hz frequency is a millions times higher than the power frequency.. so the reactive value is likewise.
    Unfortunately, most of you wont understand all this but I hope people know someone that might help you to understand .. make educated guesses in your ability to protect yourselves, families. Please refer back to previous writings Iv made.
    Best to all.

    Reply to this comment
    • joe October 25, 02:52

      The higher the frequency the shorter the antenna needed. so the leads between solar cells is long enought to induct thousands of volts from the higher frequencies. My comment on the ultrasonic, was meant to show that the electromagnic waves can be very long, I guest I should have said that for the lower frequencies, that the wave length could be hundreds of metter long. The best analysis of the short microwaves and nanowavers will still be in the thousand plus range from an EMP pulse and in the hundreds of volt range at the low frequencies.

      Reply to this comment
  58. Jack October 25, 05:53

    Im wondering, Joe, what brings you to conclude the higher frequencies has the most energy? Where do you get your figures such as thousands of volts per millimeter?
    What is your background related to electronics, radio, EMP?? How long ?
    What do you know about HOW you get all those frequencies?
    HEMP is all theory based on some experiments.. some such as Star Fish Prime.. and some such as the test done with automobiles and endless even smaller experiments. Id really like to hear what you base your conclusions on!
    Admittedly I disagree with some of what you say.. but I do not remotely believe I have a patent on my conclusions but what you are saying, particularly that there is higher energy at higher frequencies. It flies in the face of many theories and practices.
    HEMP has utterly infinite variables and conditions but I think if you have the kind of energy in higher frequencies .. THOUSANDS OF VOLTS PER MILLIMETER.. you might well be close enough to have many other problems.
    Higher frequencies are more easily absorbed by structures, dont bounce around corners (consider line of sight issues alone!). If you have another theory, PLEASE share it!
    Thank you!

    Reply to this comment
  59. Rod October 25, 17:23

    I have been following these last few comments and Jack’s last one made me think of something. How valid are the Starfish Prime and later automobile tests in today’s world? Starfish Prime was done during the early days of semiconductors but did prove electrical grid vulnerabilities. The later automobile tests I have always discounted because they quit when they disabled an automobile because the cars were borrowed and had to be returned to the motor pool in the same condition they left. Tests on cellular equipment and sites, today’s automobile designs, and today’s homes would be extremely valuable. One other thing to keep in mind is that there are now nuclear payloads that have been designed to create EMP’s as the primary weapon. These are detonated miles above the target area to create a “cone” of destruction below them. The highest EMP levels are directly below the detonation with levels decreasing as you get farther away from the center.
    We, the public, are making our plans with the best information we have, but much of that information is plainly dated and we may have situations today where that information is insufficient.
    Like I said earlier, just doing some thinking in front of the fireplace on a cold Sunday morning with snow in the forecast.

    Reply to this comment
  60. Jack October 25, 23:31

    Well stated, Rod.
    I wonder just how much more powerful of EMP these nuclear payload designs will generate today? Once again, most of us will never know. But with the target altitudes of 200-300 miles there of, our enemies have much less interest in destroying the surface, just incapacitating the people, so we have little resistance. Also, by destroying our economy.. we become inconsequential. None the less, I strongly believe targets will be largely places of military consequence, places of financial consequence. It would be a waste of resources to just blast largely empty places. Im sure there would be other places of interest.
    I would suggest people taking the best protection they can. Do the most on the most important.
    I do not believe the capacity of thousands of volts per millimeter is possible.. unless you are quite close to the blast. I could be wrong but seriously doubt it.
    An EMP blast is a PULSE. A very nearly instant pulse. Pulses are waveforms and can be broken down into multiple frequencies. One might read up on wave forms.. such as a squarewave. (what makes one persons voice different from another? Wave forms. The strongest waveform are the fundamental frequency, and multiples will lessen as they go higher.
    As for me, I dont like to say something is impossible so dont even try. As for semiconductors, I do not see how ANY semiconductor would be destroyed due to an EMP acting on it DIRECTLY.. Wires that CONNECT to the semiconductors (acting as antennas), as the wave crosses over the wire it induces a voltage which is then conducted to the PN junction (semiconductor) where, if there was enough voltage generated (a function of strength of the wave and length of wire absorbing it) applied across that PN junction, it will be permanently destroyed. My solar panels will have metal shielding over as much of the wires (especially outside the panel!).. to shield the power carrying conductors..
    The more you can do the better chance you have.
    Dont just figure its a total waste.
    If you live near a military installation, well, Id either move or plan to give up most of your electronics in the event of an EMP! If you live in a mountainous or at least hilly area.. where you have to travel thru windy roads to get to your place.. and you dont live near any place of interest as a target.. you would have a better chance, less EMP damage. When I say being away from targets, I mean AT LEAST HUNDREDS of miles, not at least 10 miles or something like that.
    Radio waves do not go around corners, they bounce and each bounce some energy is absorbed.
    Lower frequencies tend to travel better.
    Anyway, out of time!
    Blessings to all!

    Reply to this comment
  61. Dave December 21, 16:02

    I have a way to EMP-proof your entire home for under $400. I have a way to EMP-proof your car as well. I have a newly-developed, military grade device that attaches to your inverter, transfer switch or 200amp panel so that anything that is plugged into the home wall outlet won’t get fried in the event of EMP or any geomagnetic event. I’m offering a 15% discount on the item as well. Email me for details.

    Reply to this comment
    • Jack December 22, 22:37

      I think I have a pretty good level of understanding EMP.. And I hate “Snake Oil” salesman. So, for someone to tell me they have a device they can plug into the power and its going to put an “invisible shield” of some kind.. that will make all my electronics be EMP proof.. My first question is.. Where are you going to be when you have my money, all my stuff is fried.. and I cant find you to hold responsible? Let alone the cost to replace all my stuff that DID get fried… IF I even can replace it after an EMP!.
      To this “chap” Id like some kind of reason as to just HOW his device will do anything like what he claims. You might be able to short out the EMP such as with an ionizing gas tube.. but they have a delay that might not give you adequate protection if its across the power cord going to your device.. let along a house. There are circuits Iv designed and bet my systems on personally.. but I do not have the means of hard testing. I think I described such in one of my post.. a year so back.
      If asked for endorsement I could not without knowing a lot more then “Dave” gives us.

      As I was getting some eggs ready for freeze drying this morning.. I use a blender to make sure eggs are very consistent.. and such reminded me I might clean the blender with some bleach…
      This reminded me that especially today disinfectants are even more necessary! And what I did about supplying myself with a pretty much infinite amount of Sodium Hypochlorite (been a few decades since college chemistry!).. but there is a product out there.. available from SWIM. (Safe Water International Ministries).. who makes a little device that turns salted water into bleach. This is kind of a half truth; its not like commercial bleach.. but it takes the salt in the water and separates it into 2 (?) compounds, one of which is bleach. In commercial bleach the other components are separated out leaving only the bleach, and generally that is about 10% if memory serves. Regular bleach is only about 5%.
      This “bleach” you can make is fine for purifying water, wiping down counters, wash loads.. whatever. BUT, it will break down and revert back to salt water in time. Iv not tested how long but heard it last for a week or two.
      A small amount of table salt is added to a given amount of water… 12vdc is applied to the unit (this charges two plates the water is flowed across (repeated 5 times).. and presto! You have a usable bleach agent.
      Also of note.. Know how you get bleach on your hands and they feel slimy for a while, hard to rinse off??? For those not “in the know” .. this is the result of a base (pH) on your skin. Very easy to remove! Vinegar is a very mild ACID. A little deluted vinegar will reverse that “BASE” on your skin and the slim is neutralized instantly.
      I will have to write stuff like this down.. share it.. as I am reminded of things!
      Merry Christmas to all! Even you Dave! Im not the only technical person on these threads.. but Im entirely unsold on such an advertisement without ANY backup… not when all I see is “snake oil”! Show me how it is supposed to work! Convince me!

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    • Uncle December 22, 23:16

      I have purchased devices from Grainger to protect our motors and equipment from line abnormalities.

      how can your device possibly blanket all the equipment from radio frequencies that are away from it’s location not shielded at all. What I have read in this thread your device would not work.

      or are you phishing for e-,mail’s

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