[bigbob]

That’s to keep the stuff they put in them from rattling around. A Faraday cage works like the roof on your house, it’s the outside that keeps rain from coming in, not your interior ceiling. Electromagnetic radiation cannot penetrate the metal shield, this is just basic electronic physics, nothing I need to argue with anyone about.

Here’s a good demonstration, absent the usual pseudo-scientific BS:

https://www.youtube.com/watch?v=aMct99DiZak

As he says, you’d like about 50dB of attenuation to protect electronics against EMP. He test using a couple of watts from a handheld radio a foot or two away which represents about 100 dB of dynamic range and is more than needed, but still achievable with layers of shielding.

Covid 19 benefited the TP makers, and EMP threat will be great for Reynolds Aluminum.

[Bob Ireland]

For now for some reason this is the best that I can find on my tablet - which you have already labeled as 'the usual pseudo-scientific BS'; I will have to access my own computer archives later.

The skin of the metal container can become an antenna; Grounding primarily helps to keep the cage from becoming charged and perhaps re-radiating... More later hopefully.