How much do you know about EMP protection? Do you know how to protect your gear from an EMP?
On a scale of one to ten, an electromagnetic pulse (EMP) and, more specifically, a high-altitude electromagnetic pulse (HEMP) are events that rank about an eleven on the prepper’s Scary Survival Event Scale.
While all nuclear weapons create EMP, the EMP generated is massive when detonated high in the atmosphere. As a result, it can destroy electronics and permanently knock out the country’s power grid and other critical infrastructure.
Because of this, many preppers are interested in EMP protection measures for their electronics.
Table of contents
- A Note from The Survival Mom
- Factual information is hard to come by
- Just as deadly, the Coronal Mass Ejection
- Video: Why bother protecting electronics from EMP?
- What is a Faraday cage?
- How To Make A Faraday Cage
- One final note about EMP protection
- These novels portray EMP survival — entertainment AND food for thought!
A Note from The Survival Mom
There was a time years ago when the idea of a HEMP terrified me. I’d just read One Second After by William Forstchen about life in a small town following an EMP event. I even reviewed it.
However, I don’t believe that’s a realistic scenario anymore. It’s too widespread and renders critical infrastructure useless to the attacker as well.
Instead, localized EMP events, sabotage, and, to a lesser extent, Coronal Mass Ejections (CMEs) are what we need to be prepared for. For example, something along the lines of this attack on a California substation is exactly what I would expect to happen.
Having said that, let’s take a look at some facts and how you can protect your sensitive electronic gear from an EMP attack, regardless of how it occurs.
Factual information is hard to come by
The first thing we need to look at is the lack of information available about EMP and its effects. Most of what we know is from nuclear tests, both American and Soviet, in the 1960s.
Data and information after that period are still highly classified, so all we have to go on is what has been declassified from this earlier era of tests. However, this information and a few pieces of recent data are enough to make some reasonable projections.
The second thing we need to understand is that a HEMP attack on the United States is about as bad as it gets. Experts predict that 70% – 90% of Americans would die within 12 – 18 months after an EMP attack. The reason for this is the extreme dependence on electricity and the delocalization of resources, like food, water, and sanitation abilities.
EMP is survivable, but you need to start preparing for it now. Unlike other disasters, there is no warning or precursor, and no ability to “finish prepping” once it occurs. EMP is an instantaneous event.
There may, however, be a brief period of time before the masses realize what has happened is more significant than the typical power outage. Use this list of what to do immediately following an EMP to make the most of that time.
Just as deadly, the Coronal Mass Ejection
A Coronal Mass Ejection, or CME, is another event that can take out the entire power grid. When highly charged plasma particles from the surface of the sun crash into the Earth’s magnetosphere, it induces an electrical current in long lines of metal, like wires and pipes. This induction of current will destroy the transformers needed for power transmission on the grid, essentially wiping out the ability of the power grid to remain operational.
However, unlike EMP, a CME event does not destroy electronic devices unless they are connected to the power grid or long lines that will collect the induced current. Also, there are plenty of advance warnings before any solar event that might affect the planet.
This post goes into greater detail about what an EMP is, how likely it is to occur, and what the impact could be.
Video: Why bother protecting electronics from EMP?
You want to protect your gear from EMP by utilizing a Faraday container for two main reasons.
The first is that you maintain the ability to communicate via radio and generate power. This gives you a huge tactical advantage when trying to survive in a powerless world.
The second is the massive amount of information you can store in digital format. As hardly anyone today remembers how to do things the “old world” way, this information will allow you to restart your life at the mid-1800s level.
Read this post for suggestions about what you might want to place inside EMP protection.
In this video, The Survival Mom explains in greater detail why you SHOULD consider protecting some of your devices. She also discusses her opinions about EMP and other possible power grid failures. The video starts at about the five-minute mark, so you can dive right into the main topic.
What is a Faraday cage?
The Faraday cage is named after Michael Faraday, the scientist who discovered its properties for shielding against electromagnetic waves, including electricity. You can build simple Faraday cages at home at a very low cost that will work just as well as the expensive ones that the government uses. All it takes is some common household items.
How does a Faraday cage/container work?
A Faraday cage protects its contents by preventing electromagnetic energy from getting inside. Expensive Faraday units use a combination of fine copper mesh and solid aluminum. You can build your own at home using aluminum foil and a galvanized steel trash can.
By the way, Faraday shielding doesn’t actually have to be a “cage.” It’s simply any container that blocks electromagnetic radiation.
Many places on the Internet claim that a microwave oven or Mylar bag protects devices from EMP. Mylar bags of the correct thickness have been proven to be effective, but the microwave oven as a Faraday container isn’t something you can rely on.
The frequencies for EMP range from approximately AM radio to approximately FM radio. (Actually, EMP frequencies have a broader range, but the AM/FM radio comparison is close enough.) AM signals go as low as 540 kHz, and the FM radio band stops at 108 MHz. So don’t worry if those frequencies don’t mean anything to you.
The important thing to know is that you can test how effectively a container shields electromagnetic frequencies by using an AM/FM radio.
Determining if a container is effective EMP protection
It’s a simple process to determine if a container will function as EMP protection.
First, tune an AM/FM radio to a strong FM station. Turn up the volume. Put it into the Faraday cage you’re testing and listen to see if the radio station is still being picked up by the radio. Don’t get too excited if it doesn’t. As FM signals are very easy to shield against.
Then, tune the radio to a strong AM station and retest. The low frequency of AM signals is very good at penetrating objects. So if you can’t hear the AM station anymore, that’s a good sign.
Anything that can block strong AM and FM radio signals would probably make a good Faraday cage. Keep in mind, though, that the power of these signals in your home is relatively weak (unless you happen to live under a radio tower).
This is important to know because you’ll see videos online where people put their cell phones into a microwave, Mylar bag, or some other type of “Faraday” protection and demonstrate the effectiveness by showing how the cell phone loses the WiFi and cell tower signals.
Cell signals are extremely weak to begin with and are very easy to block. Therefore, these demonstrations are NOT good tests for protecting against EMP.
A food-grade Mylar bag won’t even stop 11 watts of WiFi signal (a 2.4 GHz frequency) from reaching my iPhone when it’s right next to the wireless router. It certainly won’t stop the destructive pulse from EMP.
My EMP protection measures tests
While looking for an inexpensive way to protect my electronics from EMP, this author personally tested several methods. As I mentioned, the tests are imperfect because we’re only testing for a certain range of frequencies. However, it’s still possible to obtain good information from these tests.
One test involved being on top of a mountain filled with radio antennas. The collective power of all these radio towers was 9,000,000 watts of RF (Radio Frequency) energy! Another test was standing at the base of a 50,000-watt AM station.
What EMP protection DIDN’T work?
Using the AM/FM radio test, I found that both Mylar bags and microwave ovens were unsuitable for Faraday cages. Both of these failed inside my home.
They did not work well at all.
When I tuned an AM radio to a strong station and put it in the microwave, I could still hear the station. This is because the shielding on a microwave oven is tuned to block out signals in the 2.4 GHz range, the same as most WiFi routers (most cell phones are close to this range, too).
Thus, when you put your cell phone in them, it’s not surprising that they lose signal. They can also block out most FM radio stations. However, because of the nature of longer radio waves, AM signals pass right through the shielding found in the modern microwave oven.
Because Mylar bags are much easier to transport than a microwave oven, I tested them at the radio antenna sites. Unfortunately, the signals still got through, even tightly wrapping the radio in two Mylar bags. In fact, the Mylar bags didn’t seem to reduce the RF radiation at all. EDITOR’S NOTE: The thickness level of the Mylar bag used in this test is unknown.
What EMP protection DID work?
It turns out that a very effective EMP protection measure, or shielding, can be made from aluminum foil. Common heavy-duty aluminum foil successfully blocked all nine million watts of RF energy from reaching the radios. The radio needed to be wrapped in three layers, but it worked! For AM signals, though, I needed five layers to block out the RF energy successfully.
This means that you should be able to easily protect your electronic gear from EMP simply by wrapping it in aluminum foil. I also found that placing the foil-wrapped radio inside a galvanized steel trash can significantly increase the effectiveness of the shielding.
Learn what you absolutely must do in the first critical hours following an EMP or other massive power grid failure.
Make every second count.
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How To Make A Faraday Cage
The hardest part about protecting your electronics is simply doing it. However, a few rolls of heavy-duty aluminum foil, some cardboard boxes, and a galvanized steel trash can are enough to create your own Faraday cage and provide EMP protection. You can also buy faraday cages for smaller items.
For more information about this protection, read Survival Mom’s interview with Dr. Arthur T. Bradley here.
How To Make A Faraday Cage
- Gather your supplies.
–Heavy-duty aluminum foil. You’ll use a lot of this, so be on the lookout for coupons!
–Either plastic wrap (Saran or something similar) or plastic bags for each electronic item you want to shield.
–Pieces of cloth or sheets to wrap items. This is an excellent way to re-purpose old t-shirts, jeans, and clothes the kids have outgrown.
–Cardboard boxes of assorted sizes
–Small, essential items that contain an electronic component, such as a clock radio, a hand-crank weather radio, walkie-talkies, ebook/Kindle, mp3 player, etc.
Make sure these aren’t things you’ll want or need in the near future. If you don’t already have duplicates, make a list of what you want to be stored in your Faraday container. Then look for inexpensive duplicates at garage and estate sales.
- Prepare each electronic device for wrapping.
If your device has an antenna that doesn’t retract or fold into the device and can be removed, go ahead and remove it. Likewise, for any cords or wires. Removing these is unnecessary but can make it more challenging to wrap.
You don’t want to risk protruding parts poking through the foil, as this will void any EMP protection. Ensure that any wires, cords, and antennas are within the foil.
If the device has a removable battery, remove it and store it separately. The last thing you want is to find out that the batteries leaked and ruined the equipment that you went to so much trouble to protect.
What if you want to protect devices that have internal batteries that can’t be removed? Many of these items would be helpful in a post-EMP world, but you’ll need to determine a way to store them and periodically recharge the batteries.
- Wrap each item to isolate it from the foil.
When you wrap your electronic device, it’s essential to prevent it from touching the foil. Otherwise, it’s like making an antenna for the EMP to get right to the item you’re trying to protect.
You can prevent this by wrapping the device in paper, wax paper, an envelope, or a cardboard box. Whichever works best for whatever you’re wrapping in foil. If the device has protrusions, it’s best to wrap it in something thicker than thin plastic wrap or paper. Use a box or envelope of some sort. This will help keep the item from poking through the foil.
You can use anything non-conductive to wrap the devices. Here I used an old sheet and plastic wrap. The cloth sheet prevents “pointy” parts of the device from poking through the foil, while the plastic wrap keeps the cloth holding the fabric in place.
I could have used tape, but the plastic wrap is reusable and I can see through it to make sure that the cloth is in place. Also, I don’t use plastic wrap directly on devices, as I don’t want any letters or print on the device to get stuck to the plastic in long-term storage and come off when I remove the wrap.
- Wrap each device in foil.
Wrap each item in the foil, ensuring that all device surfaces are covered in a minimum of three layers. Gently mold the foil each time, making sure there are no holes or rips. In tests that I’ve done, wrapping each layer individually seems to work better than folding the foil into a double layer and then wrapping.
However, you don’t have to wrap up every item individually. Instead, you can save time and space, and avoid the need for cloth and plastic wrap by putting several devices into a small bag, cloth pouch, or box.
Once you have all of your devices wrapped in several layers of aluminum foil, you’ve taken a big step in protecting them from EMP. You should, however, place all of these foil-wrapped items into another layer of Faraday protection. An EMP is an extremely powerful pulse. Every layer between it and the device diminishes its ability to destroy electronics.
If you’re not going to be storing these foil-wrapped items in another Faraday container, then make sure to wrap five layers of foil around the device.
- Prepare the container.
One of the easiest ways to do this second layer is to put the wrapped devices in a galvanized steel trash can. With a tight-fitting lid, it’s surprising how well this works.
Because you need to keep the items inside the can from touching the inside metal of the can, line the trash can with cardboard. If a foil-wrapped item touches the inside of the can, it’s like there’s only one level of protection, and could end up focusing the EMP directly towards the device. Not a good thing.
Once you have your items wrapped and your can lined, place the items in the can and put the lid on. You may want to duct tape the lid so it doesn’t accidentally get knocked loose. Any gap between the lid and the can and it loses its ability to function as a Faraday cage. If you have space, go ahead and wrap the items in more cloth. This further protects them from accidentally shifting and causing a tear or hole in the foil when you move the can.
You’ll find there’s a lot of room in a 31-gallon trash can. Pack the items that can be left sealed in foil indefinitely on the bottom. Then, on the top, place the things that need to be checked on or have their batteries charged.
Alternatively, you could use several smaller steel cans with lids rather than one large one.
If you happen to fill the can with equipment, make sure you place a cloth or other non-conductive material on top so that nothing can touch the inside of the can lid or the top around the sides.
Also, make sure that you have metal-to-metal contact between the lid and the can. Don’t put paint, tape, or anything that would get between the can and the lid, as this would likely render the can ineffective as a Faraday cage.
Tips for Success
For the best chance of success, remember these things:
- There must be a minimum of 3 layers of aluminum foil surrounding the device.
- Use a minimum of 5 layers if you’re not going to be using the second layer of shielding, e.g. the metal trash can.
- The foil must not contact the device directly, so first, wrap it in paper or cloth. I use cloth.
- The foil-wrapped device must not touch the inside of the outer Faraday container.
- For the Faraday cage to be effective, the metal must completely surround the protected device.
- Use heavy-duty aluminum foil; the thicker, the better.
One final note about EMP protection
Should an EMP attack ever happen, don’t rush to open your Faraday cage and start pulling out your gear. The enemy may pop off the first EMP and then wait a few days or a week before popping off another one. This way, they could ensure that they are destroying as much as possible. Read more about what to do immediately after an EMP here.
Consider having two sets of gear in separate Faraday cages. The first one would be small and only have a few items, like an AM/FM/Shortwave radio and a few walkie-talkies. Your second one would be larger and contain all of your main gear, which you would open only after a reasonable amount of time or when you needed the equipment inside.
As you can see, EMP protection isn’t difficult. Unfortunately, EMP will destroy most electronic equipment and take out the power grid. However, by taking simple precautions now, you can ensure that you have functioning equipment to make the transition to a whole new way of life a little easier.
These novels portray EMP survival — entertainment AND food for thought!
- 77 Days in September by Ray Gorham
- Cyber Storm by Matthew Mather
- Dies the Fire: A Novel of the Change by S.M. Stirling
- Grid Down Reality Bites by Bruce Hemming
- Going Home by A. American
- Into the Darkness by Doug Kelly
- Land by Theresa Shaver — Watch my video review.
- The Last Layover by Steven Bird
- Last Light by Terri Blackstock — Christian fiction
- Lights Out by David Crawford — One of the first books to focus on EMP and is still a very good read.
- Lights Out by Ted Koppel — non-fiction. Reviewed here.
- Outage by Ellisa Barr — Here is our review.
- The Perseid Collapse by Steven Konkoly
- Post Grid: An Arizona EMP Adventure by Tony & Nancy Martineau
- The Wandering Highway by Ike W. Warren
Do you use Faraday cages to protect gear from an EMP?