DIY Faraday Cages

Spend much time researching the impact of an EMP (electromagnetic pulse) and you’ll no doubt run across references to Faraday Cages. Without getting into all the physics of how they work, basically they shield electronics from the effects of an EMP.

You may not realize it but you likely already have a working Faraday Cage in your home right now — your microwave. These are said to work very well with insulating against EMP. Check with your local Freecycle groups as well as perhaps Craigslist to see if you can acquire an older microwave oven, working or not. Cut off the power cord as close to the body of the oven as you can. Place your electronics equipment inside, close the door, and place it on a wood shelf or on top of some other non-conductive material.

Another way is to obtain a galvanized trash can. The trouble though is to ensure a complete seal to prevent any of the EMP getting inside. What you can do is crumple aluminum foil around the lip of the can before putting the lid on tight. Inside the can, use wood or cardboard on the bottom for something to rest your items on and make sure none of those electronics are touching the sides of the can.

What should you put in your homemade Faraday Cage? Well, I’d not bother with things like cell phones. If an EMP were to hit, whether as the result of a solar flare or from some type of attack, odds are pretty good cell phone towers won’t be operating. Instead, I’d add a crank powered radio to keep apprised of news. Consider burning a few CDs or DVDs with copies of important papers and other information. While EMP shouldn’t really affect those disks, putting them in your Faraday Cage will help you know where they are. If you have an old laptop, maybe add it to your cage as well. While the power will be out, probably for some time, if you can rig up a solar battery charger, or find someone who has one, you’ll be in business. Two way radios would be another welcome addition. If you have diabetics in your group, having access to a working test kit would be very helpful.

What other electronics would you want to try and protect in a Faraday Cage?

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Jim Cobb

Jim Cobb has been a student of survivalism and emergency preparedness for almost thirty years. As a young child, he drove his parents nuts with stockpiling supplies in the basement every time he heard there was a tornado watch in his area. Of course, being a child, those supplies consisted of his teddy bear, a few blankets and pillows, and random canned goods he grabbed from the kitchen cabinets. Later, he was the first (and likely only) child in his fifth grade class to have bought his very own copy of Life After Doomsday by Bruce Clayton. Today, he is a freelance writer whose work has been published in national magazines such as Boy’s Life and Complete Survivalist Magazine. He is a voracious reader with a keen interest in all stories with post-apocalyptic settings. He maintains the Library at the End of the World blog and is also the Content Director for He currently resides in a fortified bunker in the upper Midwest, accompanied by his lovely wife and their three adolescent Weapons of Mass Destruction. Jim's first book, Prepper's Home Defense, was published late 2012 and his second book, tentatively titled The Prepper's Complete Guide to Disaster Readiness, will be out in mid-2013, both coming from Ulysses Press.

4 thoughts on “DIY Faraday Cages”

  1. just curious…if you were to use a microwave as your Faraday cage, can you remove the magnetron pack and still have the “cage” work. i don’t see why not, and magnetron are not something I want to have around me on in my home. just curious.

  2. Good ideas for sure. I would assume most anything that has a completely metal exterior could be used, such as a ash pail or ammo can? I wonder if a chest freezer would work except that the rubber gasket would be a problem. I might also stick batteries and maybe two way radios and a few flashlights in my faraday cage if there were room.

    1. I have a chest freezer set up in case of EMP, I just tack welded (self tapping screwes would work) a piece of sheet metal all the way around the lid to cover the opening created by the rubber gasket. The inside is plastic lined so anything put inside is sitting on an insulated layer, I also went one step farther and added a ground wire attached to an earth ground, just grind a little paint off the freezer and screw the ground wire there. The idea is sound, reality? we’ll see.
      I have my HAM radio, flash lights, rechargeable batteries, battery charger, a couple small solar panels, laptop with redundant copies of data etc. being a large chest freezer leaves room for a lot of things. I also keep an extra alternator and battery for my diesel truck in there as that is the only thing that will stop it from running after an EMP, no computer crap all mechanical injection.

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