Building a Faraday Cage the Easy Way

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The rhetoric and antics of North Korea’s leadership has once again brought the issue of EMP back to the forefront. Recent tests run by the North Koreans have demonstrated that they have multi-stage missiles capable of intercontinental range. A 2012 intelligence report has surfaced, which shows that the North has been working on miniaturizing their nukes all along and has had missile capable nuclear bombs for several years. In addition to all this, they’ve just tested what is supposed to be their first hydrogen bomb.

Putting all that together means that the North Korean government has finally reached their goal of being able to field an ICBM that’s powerful enough to strike the United States. It’s also powerful enough to be used for an EMP attack, something that their state-run news agency is talking about for the first time ever.

Whether or not we’re going to receive that EMP attack is something that’s still up in the air; but it’s not safe to just wait and see if it happens. With as high as the risk is, we’d better be ready. That means being ready to live off-grid and self-sufficient for a prolonged period of time.

Most people say that an EMP would put us back to living in the 1800s. That’s true in one way, but the problem is, we’re not used to living that way. We’re highly dependent on electricity and the electronic devices that we use, every day. So if we want to be truly ready for an EMP attack, it would be a good idea to have some of those electronics ready, so that we could use them after the attack occurs.

Of course, that’s assuming that you and I have solar panels or a wind turbine to produce electrical power for us. While having enough of those to power everything we own is ridiculously expensive, a couple of solar panels could make a world of difference in a post-EMP world.

But we need to make sure that the electronics that we would be using are protected from the EMP, so that they will be able to be used in that post-EMP world. That’s where a Faraday Cage comes in.

Making the Faraday Cage

EMP works essentially like powerful radio waves; at least well enough that we can expect the EMP to follow the same laws of physics that control the movement of radio waves. One important part of that is that radio waves, or any electricity for that matter (like lightning) is attracted to metal and conducted by metal. This is important, because electricity will not pass through metal, but rather be absorbed into it and travel around the surface of it.

So, if we take a metal container and put things inside it, the radio waves won’t pass through the metal container and affect what is inside. That metal container would protect them from the radio waves, and it would also protect them from EMP.


The one thing we have to do, besides having a metal container, is make sure that the inside of it is insulated, so that the electronic devices we put inside the container can’t make physical or electrical contact with it. This can be done with any material that is a good insulator, such as sheets of Styrofoam sheathing, used for building homes.

The easiest way to make a Faraday Cage is to start out with an existing metal container, which is totally enclosed, like a metal garbage can. Then, we need to line the entire inside of it with our insulating material. I like the aforementioned Styrofoam sheathing, because it is cheap and easy to work with. You can buy a 4’x 8’ sheet of it for about $10. With a little construction adhesive to hold it in place, it will work perfectly.

What to Store Inside

You’ll want to store any electronics that you’d want to use post-EMP inside your Faraday Cage. These will need to be extras, essentially duplicates of the things you use every day, or will need to use in that time. Some ideas might be:


Spare laptop computer, with all your family information, your work information and any survival references you can find on the hard drive

  • Battery-operated shortwave radio
  • Battery-operated portable communications radios
  • Pump for your well
  • Spare solar charge controller for your solar panels
  • Spare voltage inverter
  • Any medical electronics family members use, such as a blood glucose meter
  • Battery charger for rechargeable AA & AAA batteries
  • Kindle or Nook e-book reader, loaded with survival and do-it-yourself books
  • Charger for cordless power tools
  • Engine computer and sensors for your car

Remember that these will probably be the only electronics devices you will have, which work, after an EMP attack. So investing in them is well worth your time and effort. In many cases, you might be the only persons in your neighborhood or town with any of them.

One surprising thing which will survive an EMP is your solar panels. While EMP does do some damage to them, it only degrades their power output by five to ten percent. Since solar panels are designed with a voltage buffer built-in, they’ll still be usable, charging your battery bank and allowing you to use your electronic devices.

So take some time this weekend and make yourself a Faraday Cage. That will go right along with keeping your powder dry and your survival gear close at hand.


Life Straw


  1. Mark,
    Good article. I have had the electronics you mentioned (less the chargers) in a home made cage of aluminum screen. I recently purchased a trashcan to take up less space to replace the cage. One question. What might an EMP do to the blocking diode (prevent current flow to the panel) on my panel?

  2. The cabling from the solar array to the charge controller will act as an antenna, blowing out the charge controller. A spare charge controller in your faraday cage is essential. In vehicles, it’s more than the computer. In most vehicles over the past ten years, there is a distributed architecture. For example, the accelerator is not a linkage anymore. There is now circuitry that measures the pressure you put on the pedal. This is vulnerable to EMP. Your list should include chargers for laptops and spare USB chargers for other electronics. Grounding the metal cage will drain charge. Some electronics will survive unless the field strength is very high. If there is warning, trip the main breakers to the house and unplug what you can as wire or cable length pick up the EMP wave. The shorter the runs, the power conducted to the electronics.

  3. I have given some thought to an EMP’s effects on a car electrical devices. I have read that any electrical device that has windings in it will be destroyed by an EMP, not just the ECM (engine computer module).There are numerous other parts such as ignition start relays, starter motors, starter solenoids, alternators, electric fuel pumps, and fuel pump relays all of which have windings. Many of these not working would result in a ‘no start’ situation. I have yet to read a comment on the effects of an EMP on a car battery. Never mind the lesser important devices such as windshield wiper motors, car seat adjustment motors, door locks, and window lifts. I am an auto mechanic, but my electrical knowledge is limited to the practical.
    Theoretically, one could build a grid, a cage of rebar around a whole car that would ‘take the charge’, so to speak. With the car sitting on the ground with its tires, it would be protected. Of course the rebar ‘cage’ could not touch the metal of the car in any way. The problem with the rebar cage is the size of the square openings. The size would depend on the radio frequency of the EMP, whether it would be effective or not.

  4. I’m wondering if a plastic garbage can will work as well? Thank you for the simple but effective information. God bless & best wishes always!

  5. No, plastic is not the same as metal for this purpose and will not protect your electronics. It must be metal. Please reread the first three paragraphs under the heading “Making the Faraday Cage”.

  6. A faraday cage for your “stuff” is of no use if your brain fries or your heart stops because of an EMP. How about an article on how to make a tinfoil hat or body suit? Seriously – I’d really appreciate that.

    • I have such a hat I’d like to sell to you, it fits the bill $29.99 Prevents being ” fried or wired” from EMPs. Just need your measurements, neck to jaw, chin to scalp

  7. I have a few questions. I have a wooden shed where I store a lot of power tools. If I were to use a light corrugated steel to put between the studs since the walls are open, would this be a way of making a large Faraday box? Should the interior roof also be ”tinned so to speak? What about the floor? That could be ”tinned” easily but is it necessary? What about my wind generator? What can one do to the housing to protect it?

  8. This is a good idea to print this. With all the possibilities from a solar flare to the N Koreans deciding to go bonkers its nice to know someone is putting the info out there. I have been wondering about it for some time now.

  9. Great Articles about EMP. I repair medical equipment for a living and have a bit more knowledge about EMI (electromagnetic interference and it’s effects than most. EMI is what EMP causes. The pulse is the interference. I think a lot of people get wrapped up around it’s electronic so it’ll be fried and miss out on the parts of how it happens, what is affected and never heard possible mitigation or what might fix the problems. The EMP Commission’s report discusses it’s testing of vehicles but most people, if they read it, fell asleep before getting there, ignored it because it isn’t as tragic as they want you to believe to bolster their BLOG or position on TEOTWAWKI, or they just didn’t understand it. Most of the cars they drove to the test site in Arizona were used and only 1 of them needed repairs that the testers couldn’t do onsite. ALL of the other 12 cars drove them home. The issues were from nothing happening to error lights coming on that shut off when the vehicle was restarted. One vehicle shut off because of testing and was able to be restarted. When tested while they weren’t running there were NO reported problems. But how will you maintain you’re car or get gas pumped out of the ground tanks to keep it going if the grid fails?…a different issue all together.
    If it was plugged into the grid, you MAY be out of luck. But if it was not and it was powered off, there’s a good chance that household electronics could survive. If you don’t have power genration capabilities then who cares, you still can make it work.
    Some electronics are built with sprayed in metal EMI shielding on their chassis for protection from things like cell phones and other radio wave interference. Ever had your cell phone ring while sitting next to your cheap alarm clock radio and heard static coming from it even when it’s off? That’s EMI affecting an uninsulated electronic device.
    One way to attempt to “fix” an issue with electronics that got “zapped” is to unplug, take out ALL of the batteries and. Let the equipment sit for several minutes. Play with any power buttons and other buttons on the device. This may help bleed out any stored energy. I like waiting 10 minutes but the time is relative to the amount of stored energy that may be in it. Then put the batteries back in and try to power up. If it works you’re in business, if not move on to something else. The cause of the above failure would be an electronic “latch”. This essentially is when a circuit gets confused because the power coming in didn’t make sense and removing ALL power allows the circuit to unlatch and reset itself.
    Man made EMP has a little different action than CME. The initial pulse is what causes the most damage, because it’s strong and faster than most lightning arresters can cycle and stop. Altitude of the “set off “ emp has a significant impact on what happens. Mountains can cause showdown in the effects but energy waves can curve around to some degree. Like a water waves coming into a bay when watched from above.
    Bottom line is that if you don’t do anything to plan ahead for being without power, within a few days all your batteries will be dead, you’ll be out of fuel for generators and cars and you will be without power.
    But look on the bright side, DHS and FEMA will always tell you help is on the way so you can just wait for them to show up.


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