Protection against EMP to save some electronic devices for future use? Large and small scale scenarios.
I was looking here for some help regarding this. Let's assume that we have really large-scale situation (like 1859 coronal mass ejection). What is possible to prepare ourselves and protect in best way. For smaller (EMP bomb?) cases it could also help of course.
Faraday cage first comes to mind - but what construction would be good? Tesla was using regular wiring to protect himself against thousands of volts. OTOH the larger structure the stronger currents may be inducted in it.
So is it possible to build "Faraday room" inside house? "Faraday house? What about building being grounded? Tesla (correct me if I'm wrong) in some paper was theorizing about currents in the ground which may appear in some situations and be thread against power plants - those could be danger for grounded Faraday cage.
Then if it's possible what currents it should be able to stand? What wiring diameter/steel plate thickness should be considered?
Or may be it's best to keep just some "Faraday boxes". With some spare (old) laptop you're still having somewhere in bottom box in the wardrobe, another for your portable harddrive which is not used so often, and another for some electronic multimeter with maybe some spare batteries (with 40-60% power lever of course)?
"Faraday building" would be of course best for keeping some car and other machines which may be crucial in post collapse world. But maybe "smaller is better" in this case? What are your opinions?
PS. This is copy-pasta post as I've mangled something first time
Posted Sep 17, 2011, 12:32 PM UTC
This is based on what I've uncovered through years of casual research. I am by no means an expert, but feel confident that I understand the basics of EMP shielding for electronics.
It doesn't take much. EMPs don't shoot out current, they merely induce an electrical current in metal they contact. This current is high voltage, low amperage, so even a very thin material (like foil) will successfully absorb and redirect an EMP.
A faraday cage won't work, primarily because the holes in the cage would need to be smaller than the wavelength of the wave it's trying to block. However, an EMP has a wide spectrum of multiple wavelengths, so a solid metal shell is better.
Honestly, placing smaller electronics inside of a shoebox, wrapping that in aluminum foil, then placing it in a second aluminum-foil-wrapped box and ensuring that the outer box is grounded somehow will protect electronics within 99% of the time.
As for vehicles, placing them inside a fully enclosed metal building should provide protection if the building is grounded, though windows and doors can provide a way for the pulse to get in, and thus should also be metal (or metal shuttered in the case of windows) and closed when not in use. EMP is generally line-of-sight, just like most other forms of radiation.
Yeah. But what then about reports that during 1859 event telegraph lines where burning? If those currents don't have so high amperage then why would that happen?
Or maybe during SHTF event this is a danger too?
There is no tmuch info about this that's why I'm asking.
As for some thinking I would go for small aluminum boxes for my spare old stuff. If I'm not going to use those anyway why not add some amusement to this? - when of course I'll find some time :)
I think that telegraph lines current where so strong because of long distances they were spread among. So: the smaller - the better. That's why I think having small boxes is better - and (by the way) construction of Faraday cage building is rather complicated stuff anyway.
You're right. It makes sense that a larger object would produce more current. I was limiting myself to practical household objects rather than miles of copper wiring. Even a steel barn-sized building would have a lot less conductivity than a few miles of copper wiring.
Like you said your not an expert. Lets ask r/science or one of those. Then we can post it here or cross post.
Well, I may not be an expert, but it doesn't take an expert to tell you that several thousand pounds of copper wiring has more electromagnetic conductivity than a steel barn. I mean c'mon.