EMP Testing Video and Faraday Cages

The video speaks for itself, but I’d like to add a little to it – for the thick-skulled among us.

A “Faraday Cage” works by redirecting a current around whatever is put inside it. The mesh commonly used does this nicely. The electrical current flows around the cage on it outer surface. What gets me charged up is how so many people assume that a mesh cage will protect its contents from an EMP.

It won’t.

The energy produced by an EMP, and the currents we see in Faraday cage operation, are two very different things. So much so that you really only need to consider one simple question when looking at an EMP protection device: Are there gaps in the thing?

Gaps allow RF energy to pass. The broad spectrum in an EMP contains some very short wave lengths. Small holes, and even slits, can allow penetration. In fact, according to Sharon Packer, nuclear engineer and part owner of Utah Shelter Systems, gaps in a protective device may function as “slot antennas.” These allow for propagation of the RF energy into the interior of the “cage.” Not what we want.

So, will a mesh structure protect your equipment? Will a metal storage locker do the job? How about the trunk of your car? Don’t bet on any of them. My favorite is a completely sealed metal box with no path to the interior, not matter how small. Solder an ammo box shut. That’ll do it. Just make sure your container is accepting no energetic visitors.


In this video, Dr. Bradley of DisasterPreparer fame, conducts tests to determine what kind of a seal works best to join a trash can and its lid. He uses a nifty setup to measure energy directed at the can, and energy receive within the can. Through various methods of sealing, you eventually get to the point where you decide, “Yes. A complete seal is best.” Notice that he hints at slot antenna effect created by a gap as small as the film of glue on tape.

2 comments to EMP Testing Video and Faraday Cages

  • That was really neat watching that video on the the faraday box works! Maybe I should look into getting something like this to store some emergency essentials in. I never thought about how much damage an EMP attack could do!

    • LP

      The power of the bomb owned the minds of nations for decades. Now, the off-shoots of the bomb are creating conditions most don’t consider. It is worth the time to study out.

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