How to Protect Your Solar Gear from EMP (Part 1)

Imagine not having any electricity for days, weeks, months or even years… no lights, no communication channels, no water, no refrigeration, no navigation systems, no gas pumping, no food transportation, no waste pumping or garbage collecting. This is the potentially cataclysmic threat that EMP poses, and the reason to plan your survival.

Understanding the probability of an EMP of sufficient field strength, during your lifetime, is sufficient to warrant action on your part to protect your devices and solar panels from it.

Which One Is Worse for My Panels?

There are differences in effect and magnitude between nuclear high-altitude EMP (NHEMP, or EMP caused by a nuclear weapon detonated high above the earth), geomagnetically induced EMP (GIEMP or EMP caused by solar weather), and nuclear low-altitude EMP (NLEMP or EMP from a nuclear weapon detonated near the ground). You have to know them in order to protect properly against their different effects.

NHEMP occurs when a nuclear weapon is detonated in the upper stratosphere or higher. Gamma rays interact with the earth’s magnetic field causing it to re-radiate a powerful EMP and scatter high energy electrons, creating a thousand times the EMP that the same weapon would cause in a lower-altitude burst.

NHEMP is not a single EMP pulse, but rather, it a pulse consisting of three separate components: E1, E2 and E3.

  • E1 is an extremely fast and brief pulse that induces very high voltages in electronics within roughly line of sight of the detonation. It affects all electronics that have sufficient conductive area, whether they are connected to the grid or not. It happens so fast (1-2 nanoseconds) that surge protection used in the power grid can’t clamp fast enough to stop it and will be disabled by it. Although surge protection with fast enough clamping times exists, it is not typically used since it’s more expensive and more commonly occurring surges are much slower than E1.
  • E2 behaves very much like lighting. Much of its effect on the grid would be protected against by lightening protection, if the lightening protection circuits were not already burnt out by E1 when E2 arrives. Like E1, E2 can also effect electronics whether they are plugged into the grid or not.
  • Unlike the previous two components, E3 induces extremely high voltages in long conductors that run parallel to the earth’s magnetic field such as power lines, phone lines, railroad tracks and metal pipelines. E3 travels through the grid, blowing fuses, destroying transformers, knocking out substations, power plants and burning out any sensitive electronics connected to the grid. Unlike the other two components, E3 only affects grid-connected electronics.

GIEMP is caused by the sun. Solar activity spews solar radiation which sometimes hits the earth and causes the earth’s magnetic field to re-radiate powerful E3 EMP toward the earth’s surface.

The affected area can be as small as a few hundred mile radius, or can be so large that it can affect the entire planet. Although the GIEMP can affect a greater area, it can’t perturb any electronics that are not connected to the grid.

NLEMP is similar to NHEMP, but it lacks the thousand-fold amplification caused by its higher-altitude sister. That’s because the nuclear weapon detonates too low to cause the earth’s magnetic field to re-radiate EMP.

How can we shield solar panels against all three components and all against all three threats? Just protect them against NHEMP, since it packs all three components and is the most powerful type of EMP.

Discover more about the effects of the EMP on “Darkest Days”.

Use Faraday Cages for Your Solar Gear…

One of the key factors in protecting our solar gear is whether it is installed and in use or is in storage and will used after an EMP. Since stored panels aren’t plugged into the grid, we don’t have to worry about E3, and we can simply use a Faraday cage to shield against E1 & E2.

Keep in mind these important principles about Faraday cages, if you start building one by yourself:

  • Current should be able to travel unimpeded through the conductive outer skin of the Faraday cage. If you use an ammo can, for example, remove the paint where the lid touches the body of the box and remove the rubber gasket since they would impede the free flow of current through the can. If you want a tight seal, replace rubber gaskets with conductive gaskets.
  • Use sufficient shielding. The cage must provide at least 74dB of shielding. We should round up to 80dB to allow for wear and tear that will occur to Faraday cage over time. 1 mil of aluminum foil provides 96dB of shielding. If you use aluminum foil for the conductive skin, be sure that there is plenty of foil on foil overlap and that the pieces seal tightly to each other.
  • The cage needs a tight seal without any gaps or holes. Because of the large frequency range we must protect against a hole as small as a ¼ inch could compromise the integrity of the Faraday cage for our purpose.
  • A ground wire is not necessary to protect the contents of the cage. A Faraday cage can protect solar panels even if the cage is suspended in a vacuum. But because large currents could be induced into conductors, it is a good idea to ground large cages to prevent electrical shock when you touch the cage to open it. The larger the cage, the more important the ground is to prevent anyone from being shocked. For a cage protecting an entire building, for instance, a proper ground is strongly recommended.
  • Make sure that the inside of the Faraday cage is lined with non-conductive material. Prevent contact between the conductive skin of the Faraday cage and its contents. Create some distance between the solar panels and the cage’s conductive outer skin so that electricity can’t arc from the skin to your panels. Current will take the path of least resistance, so arcing large gaps will not be an issue unless the flow of the current through the cage’s conductive skin is impeded like in the example of the ammo can where paint along the lid to can contact surfaces and the rubber gasket should be removed.

Since most DIY Faraday cages are either too bulky, too heavy or too delicate to travel with you in your rucksack or backpack, another solution is needed to protect portable solar arrays, portable solar chargers and other portable solar gear in your pack.

portable soalr chargers

For example, I carry a USB solar recharging device in my bug-out bag. It has 2 small solar panels that charge a battery so that the device can recharge cellphones, MP3 players, GPS’s and other electronics. When I configure my pack as an “I’m Never Coming Home” or INCH bag (or whenever I want additional solar power), I add my packable, folding solar array. To protect portable solar equipment carried in my backpack, I use lightweight bags marketed as Faraday bags to shield them.

… or a Faraday Bag

While the bags are generally a little more expensive than a DIY Faraday cage, they have a few advantages over a cage:

  • Lighter weight
  • Less bulk
  • Waterproof
  • More durable

When choosing Faraday bags, be sure to select thick, puncture-resistant bags. Make sure to find out the strength of the shielding in the bags before you make a purchase.

I haven’t been able to find a single bag that provides 80dB of shielding! Most bags are designed to protect sensitive semiconductor products from electrostatic discharge or to hide your passport and credit information from would be identity thieves so the most shielding currently offered in a bag is a little over 40dB.

Since an NHEMP could produce almost double the field strength that 40dB of shielding will protect, take the added precaution of sealing your solar panels inside two layers of bags which each provide at least 40dB of shielding.

Some shielding is definitely better than no shielding, but there is no reason to run the risk. You may not be far enough away from “sky zero” for the field strength of the EMP to weaken enough that your panels will be safe.

Lastly, make sure that the bags that you choose have a non-conductive inner layer just like needs to be installed in a Faraday cage to prevent electricity from arcing from the conductive layer(s) of the bag into the solar gear that you are trying to protect.

In Conclusion

EMP caused by nuclear weapons has three different types of effects that need to protected against.

EMP caused by the sun will not affect devices that aren’t connected to the grid.

Solar panel & electronics stored in inexpensive shielding solutions such as Faraday cages and Faraday bags are only protected from E1 & E2 while they are inside their shielded storage containers!

And you know the principles involved in building an effective Faraday cage, what to look for in Faraday bags and that one layer of most of the bags on the market today is insufficient to protect against EMP.

Now you now know the basics of protecting your stored and portable solar gear against EMP in ways that almost anyone can afford!

Watch for the second part of this article HERE to learn the principles involved in protecting grid-connected solar installations like you may have mounted to your rooftop or near your home.

This article has been written by Cache Valley Prepper for Survivopedia.

Written by

Cache Valley Prepper is the CEO of Survival Sensei, LLC, a freelance author, writer, survival instructor, consultant and the director of the Survival Brain Trust. A descendant of pioneers, Cache was raised in the tradition of self-reliance and grew up working archaeological digs in the desert Southwest, hiking the Swiss Alps and Scottish highlands and building the Boy Scout Program in Portugal. Cache was mentored in survival by a Delta Force Lt Col and a physician in the US Nuclear Program and in business by Stephen R. Covey. You can catch up with Cache teaching EMP survival at survival expos, teaching SERE to ex-pats and vagabonds in South America or getting in some dirt time with the primitive skills crowd in a wilderness near you. His Facebook page is here. Cache Valley Prepper is a pen name used to protect his identity. You can send Cache Valley Prepper a message at editor [at]

Latest comments
  • Can you use sheet metal on the outside of a wood storage shed? Can you also use shipping containers with wood shelves?

    • Part II of the article will be published tomorrow and it goes into more detail specifically about protecting a structure and its contents. You sure could use sheet metal, but don’t forget that you must shield the floor too. The whole shell needs to allow the free flow of electricity so special attention must be paid to where the sheets join, windows, doors and where they seal. The level of difficulty of protecting the shed’s contents would increase if it is connected to outside power. Be sure to read Part 2 tomorrow since it goes into greater detail on this type of project.

      • I need to be able to put in a small vehicle. Could you also speak to how it would work with tires on the vehicle? The vehicle is solar powered.

        • Deez,
          Read Part II and if you still have questions about that, ask again and I’ll answer your question in the comments section of Part II, OK? That should be easier since Part II goes into how to shield installed panels and larger spaces, but I’d be glad to go over some of the aspects of shielding a vehicle for you. But keep in mind that it’s a lot harder to shield an electric vehicle than an older vehicle that uses a gasoline or diesel engine.
          Thanks! – CVP

  • Will an EMP damage batteries? … Such as AAA, AA, C and D cell alkaline batteries … and Lithium 3V Batteries CR2032 … or 123A 3 Volt Lithium Batteries … I can protect my electronics in double EMP Cover EMP bags — Beyond Mil-Spec. EMP Cover bags … Tests at NASA show up to 49 dB of protection (Average 45 dB) but don’t know if the batteries also need to be protected.

    • XLBadger,
      The short answer is, “EMP can affect some small batteries, so shield them.” But this is a VERY important question and I’d really like to write an article (or perhaps a paper) addressing this topic since there is so much lousy advice circulating about it online. I shouldn’t leave long answers in comments, but I don’t want people to die either. The truth is that some batteries will be affected and some will not. Saying that something is EMP-proof is kind of like saying it’s “bulletproof” … or “non-lethal.” Just as bulletproof was changed to “bullet resistant” and “non-lethal” was changed to less-lethal, the idea that a particular piece of equipment is “EMP-proof” must change to EMP-resistant, emp-shielded or emp-hardened. Quantifiable standards must be established and used to properly qualify the claims of products and so on. Although small batteries of a given type (such as AA) may look the same on the outside, many differences exist on the inside. The internal circuitry inside the battery matters. So does whether or not the battery is installed in a device, the length of conductors in the device, it’s conductivity, whether or not it is connected to the grid or other long conductors, whether or not the device is turned on, whether or not the device has fuses (and the properties of the fuses), the field strength of the EMP, the distance of the EMP, whether there is any shielding between the battery and the EMP, even the orientation of the battery and the shape of the earth’s magnetic field lines between the battery and the source of the EMP will factor in. Some small batteries have very vulnerable microelectronic charge controller circuitry in them. It’s a safe bet that newer battery designs will make use of more microelectronics and become increasingly more vulnerable. Some contain mostly chemicals and conductors. Some batteries lack the conductor length to be affected by E1 or E2, but will still be vulnerable when installed in a device that is vulnerable or that is connected to the power grid. Soviet high altitude nuclear testing in Kazakhstan in 1962 damaged very simple diesel generators that lacked any electronics whatsoever, and those tests only yielded 10-20% of the EMP field strength that we are trying to protect against. So, I hope that if you read somewhere online that small batteries won’t be affected by EMP, you will know better. I store my batteries in battery organizers and remove batteries from stored electronics in order to prevent oxidation on contacts and to prevent battery leakage from damaging the the electronics. I store the organizers on top, inside Faraday cages, where they are easily rotated and maintained. Electronics in my pack are stored in organizers in Faraday bags. Even if EMP wasn’t a factor, I would still carry my batteries in organizers so they wouldn’t short out on each other or other conductive gear.

      • Hi, I presume the generators were under load, or at least cycling, if they were damaged, correct? The generators were included in the test, or just a “bonus?” This sort of information is both fascinating and frustrating, because if an inverse square law is in effect, it might be better to avoid ground zero type incidents through selective site choices, than to prepare for the the worst as its statistical relevance decreases. Very interesting subject, thank you for the field vs cage and Db pragmatism.

        • My understanding is that the generators were running and connected to energized and monitored sections of overhead telecom cables. More than that would be conjecture on my part, but I was surprised to hear it. But just Compton scattering was once new to us, we are constantly learning about new properties of EM energy. A couple of years back we learned about new threats to spacecraft from “killer electrons.” I think the important thing to take away is that the USSR was ahead of us in EMP research when we signed the high altitude test ban and most of what we think we know is largely theoretical. Like all of academia, part of it is right and part of it is wrong. Trouble is we don’t know which part. That and that the well-funded research us the US is all classified.

    • Not to take issue with the author, as I find the article to be informative and generally accurate. However, I do not see any mechanism in which freestanding electrochemical batteries could be damaged by an EMP. The radiated fields are not nearly enough to break down the materials within the battery, and there are no solid-state junctions that could be damaged by excessive current. If someone would provide a technical explanation of any such mechanism, I would very much like to hear it. I ask this as an electrical engineer with a PhD and a background in microelectronics and electromagnetics.

  • Since making and storing a faraday cage is more challenging for a 4′ x 8′ solar panel, are there any alternate ideas?

    • DeanBob,
      It is possible to shield larger panels and even panels installed on your home. Even solar panel installations tied into grid-connected home wiring can be protected. Part II of this article, which will be published to tomorrow, has some specific recommendations on the subject so be sure to check back . If you still have questions or if it raises additional questions, I’d be happy to answer those too.

  • so i understand that the electronic components need to be protected, but are you saying the panels need to be in a faraday also? if so could you elaborate more? my system isn’t portable without a vehicle.

    • Washington Prepper,
      Yes, whether your solar panels are mounted on the exterior of your vehicle or carried inside, they would be vulnerable to EMP unless you take steps to protect them. Part II of this article, which will be released tomorrow, will talk about what is involved in protecting larger volumes and installed panels. Your vehicle should be made as EMP-resistant as possible, which would be a good topic for another article (or an entire book), but I’d be happy to give you some pointers on what’s involved in protecting your vehicle once you’ve read Part II of this article since it talks about shielding larger volumes and installed panels, so be sure to ask again after you’ve read part II so I can address them both together. Maybe we could even talk the editor into publishing a part III covering vehicles or a companion article to an existing Survivopedia article on protecting autos from EMP.

  • Guess this won’t work for a solar array of 30 panels with 6,000+ watts per hour. What do we do with those? We can’t put them in a metal container or a shed. They’d be useless. Would grounding help?

    • Intrepid Prepper,
      Fortunately, solutions exist for installed arrays as well. Part II of this article will be published tomorrow and it’s about the principles of protecting installed solar arrays and larger spaces so be sure to check back. I’ll check the comments and answer any questions that you still have. Thanks for reading and commenting.

  • Can you verify “for a fact” that aluminum will function as a Faraday Cage? Based on my understanding of electromagnetism, I do not believe it will. A magnetic field passes through aluminum, whereas it magnetizes steel. A steel box or “cage” basically stops the inward flow of the magnetic field much the same as if it was placed in flowing water, it would take on the same temperature of the water while shielding the contents from getting wet. Since aluminum does not become magnetized, it does not stop the flow of the magnetic field. Am I wrong? If so, please explain.
    Thanks very much.
    PS, I would suggest storing batteries in a Faraday Cage kust in case.

    • SkyDeep,
      Yes, I know for a fact that 1 mil thick aluminum foil provides enough shielding to protect against EMP of up to 50 thousand volts per meter. I think that it would be more accurate to refer to Faraday cages as Faraday shields. Faraday cages work because they are made of electrically conductive materials as opposed to magnetic materials. Faraday cages protect their contents from external electrical fields but magnetic fields penetrate them, and that’s fine. EMP damages electronics by inducing high voltages in them as opposed to exposing them to a magnetic field. So a Faraday bag can protect electronic contents from electrostatic discharge or EMP, yet you can’t stick magnets to them.
      Thanks for reading and commenting.

  • An electromagnetic wave striking a conductor generates a current in that conductor. Your solar panel, the leads to the battery and the regulator are all conductors and will have currents induced in them.
    The amplitude, frequency and polarity of the wave(s) which impinge upon your equipment will be the determining factors in estimating the damage which will ensue from an EMP.
    A Faraday cage fully encloses that component which it is designed to protect.
    That includes the solar panel, and its electrical output wires.
    Shielding the solar panel with a conductive medium will of necessity reduce the effectiveness of the panel by diminishing the amount of light it receives.
    Shielding the output wires requires encasing them in a grounded conductive shield which is grounded at one end only to prevent ground loops.
    The amount of EMP protection and the efficiency of the system will be a tradeoff.
    Since we don’t know the frequencies involved in a potential EMP threat we must design for a worst case scenario. That my friend would require a fine screen wire to eliminate UHF and gigahertz frequencies and there goes the solar efficiency.
    An expensive way to proceed is to NOT shield the system and allow it to operate until (and if) an EMP strike occurs. Then, after it is over, install a replacement system that you have had fully shielded and disassembled in storage.

    • Thanks for commenting Don. For shielding requirements, based on a max EMP field strength of 50,000V/m we are shooting for 74dB-80dB shielding below 64MHz so 20OPI screening will work. (We will be going over screening to allow light transmission to installed panels in Part II of the article which will come out tomorrow.) Although it certainly won’t help efficiency of the panels any, as you pointed out, the other option is to have a spare set up panels. But if there is a second EMP after we pull them out, we’re all the way back to square one. The mesh won’t effect 2nd Gen panels nearly as bad as 1st Gen panels. As must be the philosophy of Faraday bag manufacturers, since they don’t seem to make products with more than about 40dB shielding, if you aren’t right under a nuclear EMP you could get by with less shielding since some shielding is definitely better than no shielding and not every single device will be damaged. It will probably just be a fraction. But losing even a small percentage of our largest transformers would be catastrophic. I think that where the shielding could fall apart is if someone has developed a super-EMP weapon capable of generating EMPs of higher field strengths.

  • I found this article. To be very. Imformative people tend to overlook alot of catastraphic potential I remember about two years ago reading an article by a professor at MIT talking about solar storms and how it could potentially knock out entire cities powergrids for up to three years I rembered thinking people would loose their minds it would be complete social collapse.
    I do not belive a person can be prepared to survive I do how ever believe you can have the education and tools for a fighting chance to prevail and this is a good start at an education for.
    Well written research. Is educated and accurate.

    • Thank You Arman,
      You make excellent points. If only a small percentage of our largest transformers are knocked out it would take 3-4 years to get the power back since no protocol even exists to “cold start” modern power plants. In other words, we need electricity to make electricity on a large enough scale to help. And the 3-4 years assumes that we can buy transformers. And that is only if the companies we buy transformers from side with us in the War. We only have 2 such factories in the US. They only came online within the last few years because of the congressional investigations into the EMP threat.

  • Thanks for this information. I have been looking for this kind of detail for a while, but it is not easy to find.

    • Byron,
      Thank you very much, and thank you for reading and commenting!

  • Awesome article, informative beyond anything out there these days. It is my understanding that the powers that be were told of maybe an impending EMP attack on America, And I am wondering if the power companys and the government have been work on a way to secure our power plants and sub stations, In my town there is a big power generation plant, and crews have been working on it for 2 years now nonstop, But as always secure your own gear people.

    • Lonnie,
      We already have the technology available to us to protect the grid and homes from EMP, but it cost’s more money, so a utility company that implements it won’t be able to compete with a company that doesn’t. Because of this, nothing will be done to shield our critical infrastructure until we pass legislation requiring it, so vote for the shield act!
      If you want to know more about what you can do to make that happen, sign up for the newsletter at to learn more about EMP, advances that our enemies are making in the field and when legislation is being proposed. Everyone should take a moment to fill out of simple form at You fill it out once and it will send letters to your representatives and you don’t even have to buy a postage stamp or make a phone call! You won’t have to sign up again and it will help get your voice heard in a hurry.
      Thanks! – CVP

  • Can you recommend a good site for the bags?

    • Tony,
      First, I should make it clear that I do benefit in any way by recommending any particular vendor. I buy mine from The bags are 7 mils thick and have 38lbs puncture resistance. They have a non-conductive layer on the inside so all you have to do is place your gadgets inside, get rid of excess air and zip the bag shut. Just don’t forget to use two bags, one nested inside the other.
      That’s great that you are taking steps to protect your gear Tony. -Cache

  • Your information is priceless to me. I’m working on building a camp and running everything on 12 volts with a small inverter for the fridge (until I can build a water-cooled unit), furnace blower and whatever small appliances I’ll have.
    Water pump will be wind powered and the greenhouse and house heated by sun and an HHO furnace.
    This said, my concern is the 12 volt battery bank (6-8) and PWM panel. Everything else will be in metal boxes.

    • That’s great to hear Mike!
      Be sure to check out Part II of this article since it contains information that applies to the type of project that you are working on. The trickiest part will be any cable runs since they should be shielded and surge suppressed. I’m really glad that the article will help with your project.

      • Thanks~! I’ll be running any cables through conduit – throughout the camp as well AND grounded.
        As for the battery bank – I haven’t really thought about that yet. I do try to find commercially available items and “improvise” whenever possible. It’s cheaper that way and all I’ll have to do is look for something applicable. Perhaps a roof-top automotive cargo-carrier, lined with foil, will work. Your thoughts?

        • That could work if the lining was lined with a non-conductive material. It would be important to not tear the foil, use multiple layers and pay special attention to where the two halves make contact and where the conduits penetrate the shielded envelope. You would want plenty of overlap and good contact along the entire seam. Holes as small and 1/4″ could compromise the envelope over the frequency range we are concerned with, but some protection is better than none.

  • How effective is a steel pole barn as a Faraday cage? Mine has been a very good lightening rod in the past. If doors are closed and windows covered with conductive material, will there be a certain degree of EMP protection?

    • Kent Beebe,
      That’s going to depend on a few things Kent, mostly on the construction of the Barn. Check out Part II of the article as it will give you some specific pointers on shielding buildings. Keep in mind that all sides of the protected area must be shielded so you’ll need to shield the floor too. Part II mentions that you should use 20 opi conductive screening over the windows and that even very small holes could compromise the integrity of the shielding for our purposes. Other factors that come to mind are the doors, they will need to fit tightly or use conductive gaskets and if a door is open when an EMP occurs you may have gone to a lot of trouble for little gain so in Part II I recommend a foyer or mudroom entrance where only one door opens at a time, a conductive revolving door or solution along these lines. You’ll also need to shield and conductive lines or pipes running to your pole barn and use fast-clamping surge protection on them that clamps in less that a nanosecond. I hope that helps get you started in the right direction.
      Thanks for reading and commenting. – CVP

  • I am completely off grid and use a generator for back up to my 2000 watts of solar panels longest run of wiring to panels is 30 ft whats the likely hood of destruction of my system

    • Ronald,
      Since you are not connected to the grid, phone system, conductive water lines or conductive sewer lines, you don’t need to worry about an EMP created by the sun (a geomagnetically induced EMP) or the E3 component of EMP that induces high voltages in long lines like passing a powerful magnet over a long conductor creates a current in the conductor. But your system is still vulnerable to the other two components (E1 & E2), as are all of the devices in your home. So you are vulnerable to EMP caused by a nuclear weapon detonating in the atmosphere but not to a naturally occurring EMP. Check out the second part of the article to learn what’s involved in protecting your home or cabin, it’s contents and your solar array.
      Thanks for reading and for you question! – Cache

  • I love the articles and you have included a lot of very interesting info. I have to bring one thing to your attention though. When you say that we need 70+db of shielding (80db to be safe), this can’t be accomplished by stacking two 40db bags. Decibels is a logarithmic scale which means every 3db is double the protection. Stacking two 40db bags would give you 43db of protection. Hearing protection works the same way. I could be wrong on this so if anyone else is more familiar, please chime in 🙂

    • No, Mark you are not wrong, you are correct. If an NHEMP of 50,000 volts/meter occurred directly above me, the shielding provided by the bags could be insufficient. But since I live in the Rockies and an NHEMP attack would be most effective over the central US or Eastern seaboard, I shouldn’t see field strengths that high where I live. But the shielding would also be insufficient if a super-EMP weapon was used that was capable of generating higher than expected field strengths. It is likely that such weapons exist. Using very gamma-ray transparent casing and pusher layers in the construction of a nuclear weapon could result in a greater percentage of the yield being expressed as gamma rays. If memory serves, only about three percent of the the total yield has been expressed as gamma in our tests, but one of our scientists let slip in an interview that we could easily boost gamma yield to as high as 20%! Perhaps he figured that no one would understand what that meant in terms of EMP.

  • Wouldn’t it be better to use oxygen free copper for the shield?

    • Billy Bob,
      Since electricity will take the path of least resistance, the shielding only needs to be a better conductor than other materials near it.
      Thanks for posting.

  • I have an old file cabinet I want to use as a Faraday cage. Presently I have it sitting on a rubber mat on concrete slab. What else do I need to do in order to secure the items inside?

    • Tom,
      The file cabinet doesn’t need to be on a rubber mat, but make sure that the cabinet has a metal floor. You could help the electricity flow through the outer skin of the cabinet by removing paint where the edges of the drawers meet the the cabinet since non-conductive paint would create resistance and that could cause a problem. In addition to stripping the paint, you could install a conductive gasket. Even tin foil would work for the gasket. Then be sure to line the drawers with non-conductive material. Perhaps you could re-purpose that mat that the cabinet is sitting on. Thanks for reading and your question.

  • Saved as a favorite, terrific web page!

    • Thanks! That’s great to hear. Emergency preparedness is a worthy cause and contributing to the cause and the community is the primary motivation behind my writing.


  • 40 db plus 40 db equals 43 db. This is an suggestion to correct the Faraday Bag math. Decibels are logarithmic, you can’t just add to double.
    Also, I think the epic point of failure will be diodes, a circuit board design that clustered functions on to cartridges would be future_friendly. A charger inverter generator for the seventh generation would have transistor heat sink clusters, diode cartridge… unplug or built in solder bay, heat applied to one point loosens all circuit traces etc. , replace, back in business.. Shout to the heads past my moat!

  • Love your informative articles. You are so well versed on this subject and it is clear that you have researched the HEMP subject thoroughly! I have an off-grid back-up SV array of 3-100 watt/5.65 amp Poly Panels fed into a 30 amp controller and 3-105 AH Deep Cycle Batts. (Just for someone seeking a cost saving…go to an Interstate Wholesale Garage-Distribution Point- and they may give you a deal. Got by Deep Cycle Batts @$149.00 ea.) Anyway, do you feel it is OK to go ahead and place the PV’s in their original cardboard pkgs, completely cover them with .80 mil Poly sheeting, then sealing up with Heavy Duty Alum Foil making sure of complete conductance of foil…making sure all runs’s of wire enclosed. Also, as far as the Batts. Are in Plastic boxes with sealing lids. How-about double coating with Alum Foil(HD) making sure complete conductance…OK, exception to charging. Only doing any charging in daytime when home from work with “Smart” charger only until”Float” stage is reached and then re-sealing as prior to charging. DY think this is reasonable to avoid getting caught with your Faraday Down” Is it reasonable that we should get any warning at all so I would have enough time to jerk all the conductors from the charging operation and reseal the top of the batt. boxes. I have all the other solar stuff, radios, walkie-talkies, smaller batts, thermometers, electronics sealed in plastic boxes and then covered fully with Alum Foil. Pointers? Failures? Help? Thx a million!!!!!!!!!!!!!!!!!!!

    • Thank David,

      I’ll have to to give them a try. I put Interstate dual-use (starting/deep cycle) AGM’s in my vehicles so I can re-purpose them if need be. The batteries will be fine as long as they a disconnected and don’t have a built-in charge controller or other microelectronic circuitry.

      From a technical standpoint, yes, tinfoil will work, though it would be better to use several layers of nested conductive and non-conductive layers. From a practical standpoint, tinfoil is very fragile and a hole as small s 1/4″ could compromise the shielded envelope. A more practical solution would be a galvanized steel trash can with a tight-fitting lid like the Behren’s brand. If they will fit, you could put the panels inside it in their boxes or use a large zip-closure plastic bag or surplus pack liner as a non-conductive layer. Even better would be to put them inside a Faraday bag nested in the pack liner, nested inside the trash can. I am wrapping up an article on this build today if you are interested so it should be on Survivopedia in the next week or so. I like this build because the contents are still convenient to access for testing, maintenance and use if needed.

      Thanks for reading and thanks for the question! It’s really important that folks here in the US prepare for this threat as the USA is especially vulnerable to it. Prepare for all known threats of significant risk that we are highly exposed to as well, but this one keeps a lot of emergency planners up at night and Obama’s executive order was an unfunded bad joke.

  • Certainly if a nuclear device was activated overhead electricity may not be our biggest concern.

    • Thanks for commenting. : )

      Actually, a singular detonation of even a tiny nuke in the upper atmosphere could affect almost the entire lower 48 states, and that altitude, you could be directly below the vast majority of nuclear weapons and suffer no kinetic effect and no fallout since it would not suck a bunch of dirt up into a mushroom cloud. The lack of electricity would not produce nearly as many immediate casualties as long-term casualties.

      It might crash planes and would affect folks on life support or in other similarly vulnerable situations, but the largest number of dead would be from starvation and diseases that would be preventable today.

      This is because it wouldn’t just knock out electricity temporarily, but would fry large step-down transformers that have delivery times measured in years and are all custom-built. We couldn’t move fossil fuels.Internet and banking would be down. Only radio communications would work, which would reduce communications to a tiny trickle. Food production and distribution would be crippled, as would water-treatment. Waste would pile up. Rivers would seen be teaming with cholera and E. coli.

      The power being down for minutes is an inconvenience, but the power being down for months or years would result in mass migrations, competition for resources, disease, starvation and violence.

  • Decibels are logarithmic. 80dB is not double 40dB. What it is depends on the units you are looking at. If we are talking power (say dBm) then a doubling is roughly 3dB. A voltage is roughly 6dB. Thus 80 is approximately 2^13 times as much as 40.

    Good luck surviving.

  • Very well written and usefull information. Thank you
    It does look like it may be from awhile ago.

  • The author is obviously not an electrical engineer. The following statement is 100% incorrect, “Make sure that the inside of the Faraday cage is lined with non-conductive material. Prevent contact between the conductive skin of the Faraday cage and its contents. Create some distance between the solar panels and the cage’s conductive outer skin so that electricity can’t arc from the skin to your panels. Current will take the path of least resistance, so arcing large gaps will not be an issue unless the flow of the current through the cage’s conductive skin is impeded like in the example of the ammo can where paint along the lid to can contact surfaces and the rubber gasket should be removed.”

    The E1 EMP component will induce large voltages on the outer surface of conductors, but a well-built Faraday Cage will have NO induced voltage on its inner surface, nor will there be any current flow from the outside of the cage to the inside of the cage and on to its contents. This false information gets repeated again and again on various EMP prepper websites. Sad to see it here again. Learn about “Skin Effect”, “charge behavior”, and the difference between static voltage and current flow. I recommend that this article be taken down and revised as it is providing significant misinformation mixed in with what is correct.