How To Build A Faraday Cage & What To Put In It

By Just In Case Jack | Last Updated: March 27, 2023

Faraday CageWhen folks first hear about Faraday Cages, they have an initial wave of basic questions…

  1. What is a Faraday Cage?
  2. Why should I care?
  3. How do I get my hands on one?
  4. What should I put in it?
  5. Do they work?

You ask the first question because maybe you overheard someone else talking about one.

Perhaps you’re unsure what all the hype is about and want to know, “what is it”?

You ask the second question because once you know “what it is,” you’re still confused about why it matters to you.

But once you fully understand why it matters, the next question is, “how do I get one?” followed by, “what should I keep inside of it?”

So that’s how I wrote this article. To answer all your faraday cage questions and more.

So we cover the following topics in great detail:

**Note: You can skip ahead to any section of this article using the navigation links above.

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What Is A Faraday Cage?

In simple terms, a Faraday Cage is just an electronic isolation chamber. Or even more simply, it’s a special container that prevents electrical signals or waves from passing through it.

A basic way to think of a Faraday Cage is it allows any electrical pulses to go around the container.

They work by enclosing a specific area in a layer of conductive material (usually a metal). This outer conductive layer creates a “protective skin.”

This then blocks electrical signals from passing through the box.

Inside the enclosure, electronics are separated from the outer conductive skin. This is accomplished using a non-conductive insulator such as cardboard, plastic, glass, or wood.

These enclosures can be any size, large or small. So long as there’s a complete layer of skin and any gaps are small once openings (doors, etc.) on the surface are closed.

Faraday Cage Uses

One of the best ways to understand how something works is to share a few examples of them out in the real world. Here are just a few of the uses for Faraday Cages.

Engineering Design and Testing

In the world of engineering, large versions of these faraday isolation chambers are used. They help block any outside interference when designing and testing sophisticated electronic devices.

Scientists can see how certain electrical devices react without other signals in a Faraday cage. It’s used as a controlled vacuum for electrical testing purposes.

These engineering Faraday Cages also help determine if a device emits any unintentional or harmful radiation.

For example, the antenna in your cell phone was likely tested in such a way. This was to ensure energy transmitted during use was safe for humans. To prove no energy was “leaking” at frequencies outside the cell phone spectrum.

But the Faraday cage isn’t just for lab settings and engineering facilities. In fact, you’ve likely used or passed through several of them today.

Microwave Ovens

The mesh screen in the window of your microwave is part of a Faraday cage. It contains the high-energy microwave radiation responsible for reheating your leftovers. And without a Faraday cage, this radiation would leak out, cooking the rest of your kitchen.


In some elevators, cell phone “dead zones” are also unintentional Faraday Cages. The metal elevator doors act as conductive skin, thus blocking cell signals.

And it’s why you should remain in your car if a power line falls because the vehicle’s metal body acts as a Faraday cage.

It directs dangerous electricity around the vehicle, allowing the energy to pass harmlessly into the ground. Isolating and protecting the passengers inside.

How about one more interesting example?

Spy Prevention

In 2013, the Vatican used a Faraday cage to shield the Sistine Chapel. They wanted to prevent electronic eavesdropping during the selection of the new pope.

So even if someone planted an electronic “bug” into the room, it couldn’t send a signal out to the world.

So as you see, Faraday Cages have some real-world applications.

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4 Reasons Why You Need A Faraday Cage

“I do not know with what weapons World War III will be fought, but World War IV will be fought with sticks and stones” – Albert Einstien

A survivalist (like yourself) should build a Farraday cage for many reasons.

A well-constructed Faraday cage will give your sensitive electronics a layer of safety. To protect them from damage or even to prevent signals from reaching others.

Here are four great reasons to build and use a Faraday Cage for survival and preparedness:

Reason 1. Prepare For A Massive Solar Flare

A solar flare is an explosion on the surface of the Sun. The occasional massive blasts produce a burst of electromagnetic radiation, including X-rays.

Scientists classify solar flares into three groups according to their X-ray strength.

The strongest are X-class flares. These are significant events and can trigger radio blackouts around the world.

M-class flares are medium-sized. They can cause brief radio blackouts that affect Earth’s polar regions. C-class flares are small with few noticeable consequences here on Earth.

It’s not a matter of IF the earth will experience another strong X-class flare; it’s a matter of WHEN.

A Faraday Cage helps you prepare for the next massive X-class solar flare event. Keeping some of your backup electronic devices safe.

NASA | X-Class: A Guide To Solar Flares

Reason 2. Prepare For An Electromagnetic Pulse Attack (EMP)

The rise of nuclear powers around the world is growing. As well as the instability in global politics. This leads to rising concerns over the real possibility of a future nuclear attack.

All nuclear explosions create an EMP blast. But, some designs can cause a more significant EMP effect than immediate destruction.

These designs are called “high-altitude electromagnetic pulse” (EMP) weapons. They explode high in the stratosphere. And they use the Earth’s magnetic field to reflect and enhance the EMP effects.

Watch the following two videos for a more detailed explanation of the threat of a large, widespread EMP attack.

The facts about EMP and Faraday Cages

Electromagnetic Pulse (EMP) How a Faraday Cage Saves Electronics

Reason 3. Prevent Cell Phone Tracking

I know it sounds like the plot of a spy movie, but nearly all modern cell phones are equipped with a GPS chip.

From the newest smartphone all the way to the most basic flip phone.

This feature gives you the ability to use your phone for navigation. But it also allows mobile providers information about your location (past and current).

Authorities often share these location records during criminal investigations. And also during search and rescue operations.

This information is supposed to be stored for a limited time only. But it’s unclear how long companies keep these location records. And it’s also unclear who can request access to these records.

But, if you block the cell signals to your phone, you also prevent the ability of the GPS to track your phone.

A Faraday bag like this Stealth Anti Signal Forensic Faraday Bag can keep your location and movement private from prying eyes.

Review of a Cell Phone Faraday Bag

Reason 4. Prevent RFID Skimming

These days, “electronics” are no longer limited to “things with a battery, a wall plug, or an on/off switch.”

More of the cards in your wallet contains RFID security chips. These chips are designed to make mobile payment and verification easier.

Unfortunately, the ease with which that information is shared is a double-edged sword. They also make it easier for criminals to scan the information from your credit card.

And they can do this remotely while it’s still in your wallet. But you block this criminal activity with an RFID Faraday Cage wallet (like this one from Access Denied).

If you’d rather not replace your entire wallet, you can use these RFID-blocking Safe Wallets on your credit cards with the chip.

Review of RFID Blocking Leather Wallet by Access Denied

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How To Build A Faraday Cage

Now it’s time to build your own Faraday Cage at home using some very basic materials.

I highly recommend watching each of these Faraday Cage builds before you decide. Each has some great ideas depending on how simple you want.

This first video is the cheapest DIY Faraday Cage I’ve ever seen – a cardboard box, towel, and aluminum foil; now, where’d I put my “that was easy” button?

DIY Faraday Cage

This video shows you a more elegant DIY Faraday Cage solution. However, it’s still extremely easy and simple to build.

They use a Behrens10-Gallon Locking Lid Can as their conductive metal container, cardboard as their insulator, and some aluminum tape for the seams.

Survival Tactics: How to Build a Good Faraday Cage for Cheap

Ok, take the previous video and make it even simpler. Done.

How To Make A Faraday Cage In 5 Minutes Using 3 Items

As you can see, building a homemade Faraday Cage is easy.

You don’t need a degree in Electrical Engineering to protect your electronic devices. You must follow these examples and stash a few spare electronic devices in your Faraday Cage to protect your electronics from an EMP.

But which electronic devices?

Glad you asked.

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What Should You Store In Your Faraday Cage?

I like to think about Faraday Cages in three distinct categories: Home, Vehicle, and Carry.


An at-home faraday cage can be either large or small, depending on how much you want to add.

In a home-sized Faraday Cage, I highly recommend stashing the following devices:

Communication Devices

Communication devices are the most critical electronics you should put in a Faraday Cage. I recommend adding at least one set of local communication devices (aka walkie-talkies) and one over-the-air type of radio.

Will radio communications still occur after an EMP attack? Won’t the EMP blast take down those communication lines and towers?

Maybe yes; maybe no. It’s hard to predict, and as you’ll learn below, no single blast can take down all electronics since each one is geared for different frequencies.

So I think the following devices are a good start for your home Faraday Cage.

Handcrank – Solar Radio

Adding a Hand Crank Emergency Radio to your Faraday Cage will ensure you have a radio to gather intel no matter how long the grid goes down.

This is the hand crank radio that I recommend.

Plus, it always makes sense to stash a backup AM/FM/Weather Band radio, just in case.

You can also use this hand crank radio to power up a cell phone to make a 1-2 minute call in a dire emergency.

Ham Radio

This radio setup is more for advanced prepared survivalists.

If you’re into Ham radio communications (and should be), you must add a portable ham radio to your Faraday Cage. Consider this radio a spare since you want to keep it in for a surprise EMP event.

And really, we’ll likely get little to no warning of an actual EMP attack.

A portable one is what you need if an EMP takes out your larger Ham radio setup.

Walkie Talkies

I firmly believe in preparing with a coalition. Whether that’s a survival group or just your local family doesn’t matter. In emergencies having other people you can trust is essential.

But you’ll want a way to communicate with each other on a local scale. So each member of your emergency team should stash a spare set of walkie-talkies in their Faraday Cage.

That way, if the blast does take out most exposed communication devices, you’ll still have your 2-way radios; most won’t have anything.

Illumination Devices

If the grid is down, your main source of nighttime illumination will be candles or flashlights. Candles work for a few days, but unless you stock up like crazy, you’ll eventually run out. Plus, good luck moving around at night with candles.

So you should add some illumination gear to your Faraday Cage.

Tactical Flashlight

Add a tactical flashlight to your Faraday Cage. This doesn’t need to be an expensive one.

A small single double A battery LED flashlight is ideal for this. The last thing you want to do is stash a $100 flashlight in there and then never get to use it.

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There are some tasks where a headlamp works 1000X better than a flashlight.

It’s ideal for tasks that require two hands. Without a good headlamp, you only have someone hold the flashlight or try to prop the flashlight up.

For me, stashing a headlamp is the way to go.

Hunting-Related Electronics

Night goggles are a powerful tool in a survival situation. However, they require power.

So if you want the advantage of using night vision goggles after an EMP event, then you best stash a pair in your Faraday Cage.

The same idea goes for high-powered rifle scopes.

I’m not certain these electronics will be taken out in an EMP, but if your survival plan includes hunting, don’t risk it.

Spare Rechargeable Batteries / Battery Chargers / Solar Charger

You add batteries to support your battery-powered devices. You also need the means to recharge batteries without using grid power.

So get some rechargeable batteries, a battery charger, and a portable solar panel.

Ideally, all your devices use the same size battery. The most common is the AA battery. So if you can match all your electronic devices to AA, you make your life a little bit easier. If not, you’ll need spare batteries for each battery type.

Now, you also need a portable solar charger to recharge your batteries.

Then use your batteries to power your devices like your [pocket-radio source=”FaradayCagePost” name=”Katio Pocket Radio”], Tactical Flashlight, Headlamp, etc.

USB Battery

If you pair an Anytime Charge Power Bank with a few AA USB Batteries, you can bypass the need for a battery charger.

Just recharge these new rechargeable batteries into your Anytime Charge Power Bank.

Simple and effective.

Note: Your batteries will likely be fine after an EMP, even outside a Faraday Cage. So if space is limited in your Faraday Cage, you can remove them. However, I always try to keep spare batteries for my gear with my gear.

That way, I know that I have what I need in my gear stash.

A Spare Survival Watch or Tactical Watch

Most people I know have more than one survival watch.

Why? Primarily because they are awesome.

So don’t be afraid to toss one of your spare tactical watches into your faraday cage.

That way, you won’t lose the compass and sensor features you get from your watch even after an EMP.


Now, if your “at home” faraday cage is large (i.e., a shipping container), you can stash it in your vehicle.

This works best if you always have your vehicle with you at work and home.  However, if you live in extremely cold climates, you may have to consider electronics in those conditions.

But generally, a glove box or under-seat Faraday Cage enclosure will provide enough space for a shielded spare radio and cell phone.

This would be a must if your vehicle were disabled by a massive EMP or solar flare (due to so many electronic parts). At a minimum, you’ll want to stash a spare communication system if you get stranded.


On the go, you can use a smaller pouch faraday cage like this Migeec Faraday Bag, RFID Blocking Bag.

This allows you to can keep smaller items (like your cell phone or personal radio) protected.

These can be small enough to be ideal as a piece of your bug-out bag gear, a get-home bag essential, or even your jacket pocket. Plus, it’s light enough to become part of your everyday carry.

Police departments are now using them to protect electronic devices collected as evidence.

The RFID-shielding Faraday cage wallets or even a simple RFID-blocking credit card sleeve are at the smallest end of the spectrum.

These can help protect your credit card and banking information from mobile scanners.

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Faraday Cage Myths & Misinformation

Myth 1. They Are Too Complicated To Build Yourself

People who look into Faraday cages get discouraged when they see professional installations. Ones that seem impossible to reproduce at home.

These cages often use expensive materials and highly intricate doors and openings. They help to reduce the chance of any signal transmission.

At the very simplest, you can use any metal enclosure that can work as a Faraday Cage with some modifications. Ammo cans, metal cabinets, steel lockers, and trash cans all work.

Heck, even just several layers of heavy-duty aluminum foil can do the trick. Just by wrapping it carefully around a cardboard box, it can protect small devices.

Myth 2. Chicken Wire Works As Well As Foil Or Metal Boxes

There are some discussions online that using chicken wire as your Faraday Cage conductive metal works just as well as other options. This is not a good idea.

Chicken wire provides much less EMP protection than even aluminum foil by a wide margin.

See for yourself:

Faraday Cage – Check Wire vs. Aluminum Foil

Myth 3. You Can Use An Ammo Can (without modifications)

Ammo cans don’t make great Faraday Cages without some work. First off, ammo cans typically have a gasket around the lid to help create a good airtight seal.

But this gasket is not a conductive material, creating a breach. This allows an EMP blast to penetrate the ammo can.

You also have to deal with the hinges on the backside, which are also not an ideal conductive seal.

If you want to use an ammo can, you’ll either need to modify it, wrap it with several layers of foil, or put the ammo can into another Faraday Cage.

Ammo Can Faraday Cage

Myth 4. How Faraday Cages Actually Work

There are several misconceptions about how a Faraday Cage actually works. These misconceptions create several myths about Faraday Cages, such as:

  1. Believing They Can Use A Cell Phone To “Test” A Faraday Cage – doesn’t work that way
  2. That Faraday Cages Must Be Grounded – they do not
  3. That A Single EMP Will Take Out All Electrical Devices – it won’t because different nuclear/solar EMP blasts have different frequencies (however, if an attacker used several blasts designed for different frequencies, it could do a large range of damage, or if an attacker focused solely on the grid – that would be devastating as well)
  4. That All Modern Vehicles Will Become Paperweights After An Attack – they won’t

Watch the following video for more details on these misconceptions, and pick up this fantastic educational book on EMPs.

Faraday Cage & EMP Misconceptions

Final Thoughts

Now that you’re up to speed on Faraday Cages, what will you do about it?

Are you going to take action? When?

I think you should take action right now because “I should have” and “I could have” are just poor excuses when it’s too late.

Building a Faraday Cage is simple, easy, and affordable. So no excuses; get it done.

Jason K. 

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