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Using Roofing Tin as EMP shield

EMP Information:

Corrugated metal panels: While steel can be used as a shielding material, it is not optimal due to its relatively low conductivity as compared with economically available copper or aluminum.. That said, steel is a good "1st layer".

EMP is a general term that could refer to Nuclear EMP or Solar EMP. (Lightening is the 3rd type but we can ignore that) These two EMP's are very different animals and have about as much in common as sharks and dogs.. Yes, they can both bite you, but that's about the limit of what they have in common.

To protect against a solar EMP, you just disconnect everything from your utility grid and you're done.. Since we watch the Sun 24/7, it is not difficult to know when a large CME is headed our way and you'll have many hours of warning..

Nuclear EMP is a far more complicated issue and special precautions have to be taken. Simple corrugated panels screwed together and grounded are probably not going to protect anything. That's not to say the metal shielding won't have any attenuating affect, just not much of one.

The general rule of thumb is that you need a minimum of 40db of attenuation to protect most electronics most of the time. Basically, if you're trying to protect a clock radio or a battery charger, 40db is probably fine in most situations... but if you're trying to protect a laptop or a tablet, then 40db may not be enough.. The smaller the transistors, the more shielding you need, and computers have very small transistors.. To solve that problem, we put a Faraday cage inside another Faraday cage.. we call this "layering", and every good Faraday cage will have at least two layers.

Nuclear EMP has two forms 1) Conductive and 2) Radiative.
The conductive pulse travels along wires and a surge protector will work, but it needs to be a special type of surge protector with a nanosecond response time.. Seimens FS140 ($250) is a good example with a 1 ns response.. Your Walmart computer department surge strip has absolutely no chance of working.

The Radiative component is far more difficult to deal with and generally requires a Faraday cage. A good, well sealed, steel can will give you about 25 to 30 db of attenuation.. the same can in aluminum will give you about 40 db. Stick the aluminum can inside the steel can and you have a very good Faraday cage that will protect all but the most sensitive equipment from even a hot spot.

DO NOT ground a Faraday cage as the ground itself will act like an amplification antenna...
 
So a metal box isn't good enough and you need a good quality surge protector, and just grounding it all isn't the solution and would make it worse.


Huh.

Almost like that's what I said.
 
Short_Shot said:
So a metal box isn't good enough and you need a good quality surge protector, and just grounding it all isn't the solution and would make it worse.


Huh.

Almost like that's what I said.
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Well, lets examine that then.

Short_Shot said:
EMP protection is the 21st century snake oil.
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No its not..

Short_Shot said:
Nobody knows how to do it.
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Yes we do.

Short_Shot said:
Nobody understands what *really* causes it.
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Yes, we know exactly what causes both solar emp and nuclear emp. We not only know what causes it, we know the functional mechanism at the physics level. Solar EMP is caused by our own planet's magnetic field lines.. when solar particles slam into our electromagnetic field, they make it wobble, compress, and stretch.. In other words, it moves around.. Now what happens when you move a magnetic field next to a conductor?
We also know that the nuclear emp is caused by gamma rays stripping electrons from atmospheric atoms, when then undergo a process called Compton Scattering. Google it, its interesting reading.

Short_Shot said:
Everyone thinks they need it.

EMP protection for a consumer system is essentially nonsense.

All you need is excellent surge protection on your grid connection.
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There are lots of excellent surge protectors on the market.. They are not all created equal and the surge protector needed has to be fast. Fast is not normally a measure of surge protector quality because most surge protectors are designed for lightening.

Short_Shot said:
If a solar flare occurs the surge will come from the massive antenna known as the local grid.
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That is true.
Short_Shot said:
If a nuclear bomb goes off far enough away to not die from it the grid protection above is all you need.
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That is not even remotely true. A nuclear weapon detonated 250 miles above Kansas would fry electronic devices from coast to coast. What percentage of those devices fry would depend on their location, position, and a host of other variables.

Short_Shot said:
If it goes off close enough to be an issue with the EMP on your system itself you won't need to worry about it for very long.
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That's not accurate either.. sort of accurate, but not really. It is entirely possible for a nuclear weapon to blow the windows out of your home and you still survive.
Short_Shot said:
Building a Faraday cage is not a matter of wrapping aluminum foil around your setup and head. It's a complex topic that requires substantial engineering resources and must be configured for a given frequency range.
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Actually it is.. In fact, placing your item in a box and then tightly wrapping it with aluminum foil makes for a very good Faraday cage.. when you're done wrapping, stick the whole thing in a garbage bag, tape it down, then wrap that again for a second layer and you have an excellent cage.. Getting the item out of it is another issue..

Short_Shot said:
That's kind of why you still get reception in steel buildings, for the most part, even if it's reduced signal strength.

A big metal enclosure does virtually nothing for most of the EM spectrum when it comes to emp protection and realistically makes it worse since ultimately the system inside will likely be grounded to it, or very near it.
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This statement is so broad and meaningless that it is both true and false.. Its like saying "The sun shines every day". In the context of most discussions, that would be very much false as gray cloudy days happen.. but technically true because the sun never turns off..
So true and false at the same time.
 
Further information:
Gamma radiation from a nuclear weapon strips electrons from the atoms in our atmosphere.. those free electrons then latch onto a magnetic field line coming from the planet and spiral down it.

Gamma is "line of sight", because its just electromagnetic radiation.. no different than what comes out of your flashlight, just a lot higher energy level.

The gamma strips electrons from atmospheric atoms the same way it strips electrons in your body when you're exposed to it. This is why gamma is dangerous.. When gamma goes through you, it strips those electrons from their obits around the atom's nucleus.. Because the atom now has a different number of electrons, it can lose its bond to other atoms.. Gamma will break both covalent and ionic bonds, causing the proteins in your body to break apart, causing you to die or get cancer if too many of them are affected.

A nuclear detonation on the ground does not spread gamma radiation very far because the higher pressure of our atmosphere (lots of air molecules close together), acts like an insulator.. In fact, for a ground detonation, the gamma doesn't go much further than the blast radius itself..

The dust is another discussion.

It takes mass to stop gamma.. Air can stop gamma radiation just as well as lead can.. you just need a lot more air.. Because lead is so dense, there's a lot of mass in a very small area.. but atom for atom, lead is no better at stopping gamma radiation than any other element.

This is why radiation shielding is rated by different materials. 1 inch of lead = 12(?) inches of concrete = 30 inches of soil, etc.
 
Tell you what. You build a residential emp protection system for a few hundred dollars that most people who diy this stuff expect to spend and post test results.

I'll even accept a couple thousand dollars but it better be able to protect from a nuke or massive CME event, because that's all these preppers ever talk about being worried about shielding from.

And most of them these days buy a $400 "EMP Shield" device and run to Facebook groups to tell everyone what a great deal they got and how safe they are now.

And it's just very fast reacting surge protector that might protect them from the grid but won't really protect the individual devices if the emp is localized.


That's the context I'm referring to. Those people are in the "nobody" group mentioned above.


Obviously there are actual professionals and engineers who understand the problem. They're not the ones trying to protect a 3kva inverter and solar charge controller from the apocalypse.
 
MurphyGuy said:
EMP Information:

Corrugated metal panels: While steel can be used as a shielding material, it is not optimal due to its relatively low conductivity as compared with economically available copper or aluminum.. That said, steel is a good "1st layer".

EMP is a general term that could refer to Nuclear EMP or Solar EMP. (Lightening is the 3rd type but we can ignore that) These two EMP's are very different animals and have about as much in common as sharks and dogs.. Yes, they can both bite you, but that's about the limit of what they have in common.

To protect against a solar EMP, you just disconnect everything from your utility grid and you're done.. Since we watch the Sun 24/7, it is not difficult to know when a large CME is headed our way and you'll have many hours of warning..

Nuclear EMP is a far more complicated issue and special precautions have to be taken. Simple corrugated panels screwed together and grounded are probably not going to protect anything. That's not to say the metal shielding won't have any attenuating affect, just not much of one.

The general rule of thumb is that you need a minimum of 40db of attenuation to protect most electronics most of the time. Basically, if you're trying to protect a clock radio or a battery charger, 40db is probably fine in most situations... but if you're trying to protect a laptop or a tablet, then 40db may not be enough.. The smaller the transistors, the more shielding you need, and computers have very small transistors.. To solve that problem, we put a Faraday cage inside another Faraday cage.. we call this "layering", and every good Faraday cage will have at least two layers.

Nuclear EMP has two forms 1) Conductive and 2) Radiative.
The conductive pulse travels along wires and a surge protector will work, but it needs to be a special type of surge protector with a nanosecond response time.. Seimens FS140 ($250) is a good example with a 1 ns response.. Your Walmart computer department surge strip has absolutely no chance of working.

The Radiative component is far more difficult to deal with and generally requires a Faraday cage. A good, well sealed, steel can will give you about 25 to 30 db of attenuation.. the same can in aluminum will give you about 40 db. Stick the aluminum can inside the steel can and you have a very good Faraday cage that will protect all but the most sensitive equipment from even a hot spot.

DO NOT ground a Faraday cage as the ground itself will act like an amplification antenna...
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Thank you for that information. It's nice to have someone that helps instead of instantly taking a condescending stance, because their view does no align.
A box within a box concept makes me wonder how much attenuation two layers of corrugated steel would create.
 
MichaelK said:
From defense strategy I've read, a bomb will have maximal effect being detonated 100 or so miles above ground, so assume several hundred miles in a line of sight from the detonation point.
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The NASA people (past customers of mine) mentioned warheads (bombs) are intended to detonate a mile high, strategic EMP detonations at 20 miles were the most destructive and high atmosphere detonations were the broadest disruptive.
I guess that makes sense?

I found this interesting since this thread made me go read https://www.cdc.gov/nceh/radiation/emergencies/nuclearfaq.htm
 
I thought the drill for storing a delicate electronic device was to wrap something in cardboard (as insulation from the foil), then foil. Tape with metal tape. Done. No? Or put in cardboard, place in a metal trash can, and tape with metal tape.
 
Bluedog225 said:
I thought the drill for storing a delicate electronic device was to wrap something in cardboard (as insulation from the foil), then foil. Tape with metal tape. Done. No? Or put in cardboard, place in a metal trash can, and tape with metal tape.
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Probably a lot cheaper to do something like this with backup devices than shield a whole active system, assuming you can provide enough protection and/or unpowered services are less subject to it (that part I'm unclear on).

And that way you'll have spares in case of failure, which is way more likely to occur than a nuke strike anyways.
 
Kornbread said:
Thank you for that information. It's nice to have someone that helps instead of instantly taking a condescending stance, because their view does no align.
A box within a box concept makes me wonder how much attenuation two layers of corrugated steel would create.
Click to expand...
Here's a statement that isn't accurate, but it goes a long way in helping to explain the construction.

A Faraday cage needs to be water tight. It should float like a boat.

Like I said, that's not accurate, but if the Faraday cage is water tight, then you've done a good job.
 
Short_Shot said:
Tell you what. You build a residential emp protection system for a few hundred dollars that most people who diy this stuff expect to spend and post test results.

I'll even accept a couple thousand dollars but it better be able to protect from a nuke or massive CME event, because that's all these preppers ever talk about being worried about shielding from.

And most of them these days buy a $400 "EMP Shield" device and run to Facebook groups to tell everyone what a great deal they got and how safe they are now.

And it's just very fast reacting surge protector that might protect them from the grid but won't really protect the individual devices if the emp is localized.


That's the context I'm referring to. Those people are in the "nobody" group mentioned above.


Obviously there are actual professionals and engineers who understand the problem. They're not the ones trying to protect a 3kva inverter and solar charge controller from the apocalypse.
Click to expand...
Unfortunately, the EMP Shield device is just a surge protector and I have a problem with their advertising because there is no way it can stop the radiative pulse, only conductive.

The $250 Siemens FS140 is better, and made by a company with a good reputation.
 
MurphyGuy said:
Unfortunately, the EMP Shield device is just a surge protector and I have a problem with their advertising because there is no way it can stop the radiative pulse, only conductive.

The $250 Siemens FS140 is better, and made by a company with a good reputation.
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Lol that's almost word for word what I tell them. Even the same brand, though I don't ever bother to specify a model number for them.
 
Short_Shot said:
Tell you what. You build a residential emp protection system for a few hundred dollars that most people who diy this stuff expect to spend and post test results.
Click to expand...
My Faraday cages cost me about $50 and will provide about 120db of attenuation.. so even a direct hit from a super emp weapon won't damage even the most sensitive stuff inside. I have about 26 cubic feet of storage.
Short_Shot said:
I'll even accept a couple thousand dollars but it better be able to protect from a nuke or massive CME event, because that's all these preppers ever talk about being worried about shielding from.
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You don't need a Faraday cage for a CME event. Interestingly, on a side note, it almost happened in 2012.. A massive X class flare and large CME missed our planet by just 9 days.. NASA has a special satellite designed to measure a large CME and it was completely saturated, rendering the data useless. Had that CME hit us, you and I wouldn't be talking right now and the population of Earth would have probably been cut to less than 1/4.

Missed us by just 9 days.. think about it. Feel free to google it.
Short_Shot said:
And most of them these days buy a $400 "EMP Shield" device and run to Facebook groups to tell everyone what a great deal they got and how safe they are now.

And it's just very fast reacting surge protector that might protect them from the grid but won't really protect the individual devices if the emp is localized.
Click to expand...
While that is true, the grid really is our biggest worry..

Short_Shot said:
That's the context I'm referring to. Those people are in the "nobody" group mentioned above.


Obviously there are actual professionals and engineers who understand the problem. They're not the ones trying to protect a 3kva inverter and solar charge controller from the apocalypse.
Click to expand...
The EMP problem is not all that complicated and it is not difficult to protect sensitive electronics if you put them in a Faraday cage.

The only thing that is difficult is protecting equipment that is functioning when a Nuclear EMP hits.. I think that's what you're talking about, and in that case, you are correct. Protecting equipment that is connected to outside devices (outside the cage), is extremely difficult.. Protecting a working solar system will be extremely difficult.. and expensive.. In fact, the cost of doing so would be greater than the cost of just purchasing another solar system and storing the entire thing inside a Faraday cage, which is what I did. We keep a Radian 8048, plus charge controllers and 5kW of panels inside a cage.. the panels are just wrapped at 40db of attenuation, but the inverter and charge controllers are protected to 120db inside a special cage with other items.

And remember, Nuclear EMP and Solar CME are two different animals. Off grid systems do not need to be protected from a Solar EMP.. Solar EMP's shouldn't even be called an EMP.. but whatever.. Your off grid solar system needs nothing special to be protected from a Solar EMP unless the lines between the panels and charge controllers are thousands of feet long.
 
Bluedog225 said:
I thought the drill for storing a delicate electronic device was to wrap something in cardboard (as insulation from the foil), then foil. Tape with metal tape. Done. No? Or put in cardboard, place in a metal trash can, and tape with metal tape.
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Seal it up good and that will absolutely work.
 
Yeah. My context is only the people who think nukes and cmes are actually valid concerns.

That's largely the only two things the people who ask about emp protection are ever worried about.
 
Short_Shot said:
Yeah. My context is only the people who think nukes and cmes are actually valid concerns.

That's largely the only two things the people who ask about emp protection are ever worried about.
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I don't think nukes are a big concern, but a solar CME is almost an absolute.. Another Carrington event will happen again, and probably soon... Controversial science (ice cores, tree rings, historical writings etc) suggest it happens every 100 to 150 years, and if it happens within the next 5 years, then 90% of the world will die of disease and starvation.
Before hard science, old texts have described the sky turning vivid colors.. humans back then thought it was the magical invisible sky fairy, but now we know what it really was.

The fact is, your home, and mine, are subjected to dozens of power spikes every month.. sometimes hundreds. Most of these go unnoticed and their effects are to generally shorten the lifespan of electronics, but they do little immediate damage.

Having a whole house surge protector is a good idea.. even if its not fast enough to stop a nuclear EMP, it still a good idea because lightening strikes frequently. A whole house surge protector will extend the life of your electronics, so its a good investment.

We installed one of the FS140's on our home.
 

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MurphyGuy said:
I don't think nukes are a big concern, but a solar CME is almost an absolute.. Another Carrington event will happen again, and probably soon... Controversial science (ice cores, tree rings, historical writings etc) suggest it happens every 100 to 150 years, and if it happens within the next 5 years, then 90% of the world will die of disease and starvation.
Before hard science, old texts have described the sky turning vivid colors.. humans back then thought it was the magical invisible sky fairy, but now we know what it really was.

The fact is, your home, and mine, are subjected to dozens of power spikes every month.. sometimes hundreds. Most of these go unnoticed and their effects are to generally shorten the lifespan of electronics, but they do little immediate damage.

Having a whole house surge protector is a good idea.. even if its not fast enough to stop a nuclear EMP, it still a good idea because lightening strikes frequently. A whole house surge protector will extend the life of your electronics, so its a good investment.

We installed one of the FS140's on our home.
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Right. Which is what I suggest for anything grid tied.

Regarding a cme, even if it does occur there is not any strong indication or even consensus that individual small systems will be significantly affected, rather that the grid itself will again be the source of the problem and once again that type of surge protector comes into play.
 
Short_Shot said:
Right. Which is what I suggest for anything grid tied.

Regarding a cme, even if it does occur there is not any strong indication or even consensus that individual small systems will be significantly affected, rather that the grid itself will again be the source of the problem and once again that type of surge protector comes into play.
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The problem with the CME is that it will induce about 1 volt per meter of conductive surface... That's not much for a house or off grid system consisting of 50 to 100 feet of wire runs, but thousands of miles of grid wires make it a big deal.. The voltage coming into your home can go from 120/240 up into the 30,000 to 50,000 volt range.. although such increase happens rather slowly as compared to a nuclear emp.

Still, a modern day Carrington event will fry most of the grid and set homes on fire as sparks rain out of appliances and the other crap we have plugged in. Grid transmission wires will melt down and catch whatever is below them on fire, which is what happened during the Carrington event.. even before the days of wide spread electrification, the telegraph poles had the grasses around them burned from the falling sparks and melted wires.

The consequences of a large CME would be much MUCH worse than any nuclear EMP.. Nuclear is a relatively localized event, allowing other countries to come to our aid.. with a CME, the entire world would be affected as it wouldn't matter if you're on the night side or day side. No one is coming to help.

Also, one other thing to consider.. Surge protectors are basically just shunts.. they channel the energy to ground.. when the shunt burns up, there's nothing to channel that energy any more and it goes straight into your home. Whole house surge protectors are designed to mitigate fast spikes that come and go in the blink of an eye.. they are not designed to become a heating element as thousands of amps enter your home. When the whole house surge protector gives up the ghost, your home will no longer be protected.

The wiring in your home will most likely be safe as circuit breakers will pop, but probably not before some electronic device emits a shower of sparks and sets the drapes on fire. And even if your home survives, which it probably will... you won't have any electricity for the next decade or so...

If you want an idea of what happens in real life, find yourself a variety of 120 volt appliances or electronics.. take them to an industrial factory or commercial building and plug them into the 480 volts... and watch what happens... I've done it myself.. some items just pop quietly, others are rather dramatic.
 
So what you're saying (again correct me as needed here) is that surge protection alone won't effectively shield anything from a massive cme and the problem isn't caused locally but rather from the grid so building a Faraday cage around your crap won't do anything of value to protect against the two things every prepper thinks they need to build a Faraday cage to protect from?

Preppers don't talk about shielding sensitive equipment from interference. They are always on about "nukes" and "solar flares".

There's just not enough "stuff" in the average home to really cause such a massive voltage rise during the event. Everything I've read about this suggests that simply disconnecting from the grid is sufficient to protect from a CME (which we would be aware of if you pay attention to the news) and a short duration pulse from a nuke is handled with that fancy fast acting surge protector as you've described.


Also it seems to me based on that information that fast response surge protection coupled with a slow(er) response disconnect of some sort would be the solution since both of those issues would come from the grid in the event that you aren't actively prepared to disconnect for a CME.

I'm not aware of a product that's designed to provide that sort of disconnect protection before the surge protector fails, but maybe it exists?

And if we're not grid tied then what exactly are we worried about?


As I've been trying to say the whole time building a cage for the apocalypse isn't the right answer to the problem these folks are trying to solve and at best does effectively nothing but be a cool thing you built.


As for plugging 110 devices into 480, well, I have worked with everything from 1v dc computer hardware to 480v 3 phase, though all of it is on the device/equipment/controls side of things. I'm no electrician mind you, my J card is in other things, but I've seen some things let out the magic smoke in my day I'll tell you h'wat.

Unrelated: If you want some shenanigans try dealing with a "grounded B" (corner grounded delta) 3 phase system with new electricians that haven't been in the facility before who don't think that's a thing. Watching them argue that a 0 volt potential to ground can't carry or can't currently be carrying current is amusing.
 
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