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I’m at a prepper expo in Orlando — one of those events where half the vendors are selling freeze-dried food and the other half are selling tactical gear you’ll never use. And I’m standing at a booth where a guy in a polo shirt is selling “EMP-proof bags” for $89.99 each.
He’s telling this older couple that an EMP will fry every electronic device within 500 miles. Every car will stop. Every phone will melt. The grid will go down permanently. Society will collapse within 72 hours. And his bags — HIS bags — will save their precious electronics.
I watched this couple buy four of them. $360 plus tax. For bags that were basically just anti-static bags with a zipper and a logo on them. The same kind of bag your motherboard came in when you ordered it from Newegg for like $2.
That interaction bugged me. Not because the guy was a scammer — although he kind of was — but because EMP is one of those topics where the fear is so far ahead of the facts that people make terrible decisions. They either spend thousands on stuff that won’t work, or they decide the whole thing is Hollywood fiction and ignore it completely.
The truth is somewhere in the middle. And the middle is where useful preparation lives.
What an EMP Actually Is (Without the Movie Drama)
So here’s the deal. An EMP — electromagnetic pulse — comes in a few flavors, and they’re not all the same.
Nuclear EMP (NEMP). This is the big one everyone’s scared of. A nuclear weapon detonated at high altitude — like 200 miles up — generates a massive electromagnetic pulse that covers a huge area. The 1962 Starfish Prime test over the Pacific knocked out streetlights in Hawaii. From 900 miles away. So yeah, it’s real.
But. And this is a big but. A nuclear EMP has three components called E1, E2, and E3. The E1 pulse is the fast one — nanoseconds — and that’s what fries small electronics. The E3 pulse is slow and acts more like a geomagnetic storm, messing with the power grid through long transmission lines.
Then there are geomagnetic storms — the sun throws these at us periodically. The Carrington Event in 1859 was massive. Telegraph lines caught fire. If that happened today it would be ugly for the power grid. But it wouldn’t fry your phone in your pocket. Different mechanism entirely.
Non-nuclear EMP devices. These exist but they’re short-range. We’re talking feet, not miles. The kind of thing that shows up in action movies is mostly fiction.
For prepping purposes, we care about two things: a nuclear EMP hitting the grid, and a severe geomagnetic storm doing similar damage. Both result in the same basic problem — the power goes out and it might stay out for a long time.
What Actually Gets Damaged (And What Doesn’t)
This is where the fear merchants make their money, because nobody actually knows for certain what a large-scale EMP would do to modern electronics. We have limited test data and a lot of extrapolation.
But here’s what we do know from testing and research:
The power grid is vulnerable. Long transmission lines act like antennas. Large transformers can be damaged or destroyed by induced currents. And here’s the scary part — those big transformers take 12-24 months to manufacture and there aren’t spares sitting around. The grid going down for months or even a year or more is a real possibility.
Your car PROBABLY still works. The EMP Commission tested 37 vehicles and most of them kept running. Some had minor glitches — dashboard lights, radio resets — but they didn’t just die. Modern cars have more electronics, which adds uncertainty, but the idea that every car on the highway simultaneously stops is almost certainly wrong.
Your Car Probably Survives an EMP
Despite what movies suggest, vehicle testing by the EMP Commission found that most cars kept running after simulated EMP exposure. Modern vehicles have more electronics than older models, adding some uncertainty, but a complete fleet-wide shutdown is not what the evidence shows. That said, if the grid stays down long-term, fuel availability — not vehicle function — becomes the real constraint.
Small electronics are a mixed bag. If they’re connected to the grid (plugged in, connected to long wires), they’re at higher risk. If they’re sitting in a drawer with no antenna and no power connection, they’ll probably survive. Probably. Nobody can guarantee it.
Battery-powered devices not connected to anything have the best chance of surviving. A flashlight in your closet? Almost certainly fine. Your phone sitting on a wireless charger plugged into the wall? That’s a different conversation.
The Faraday Cage Thing (It’s Simpler Than You Think)
A Faraday cage is just a conductive enclosure that blocks electromagnetic fields. Named after Michael Faraday, who figured this out in the 1830s. Your microwave is technically a Faraday cage — that’s why it doesn’t cook you while it heats your burrito.
You can build one that works for about $35.
The galvanized trash can method. Get a 20-gallon galvanized steel trash can from Home Depot. $28. Get a roll of aluminum HVAC tape — the real metal stuff, not the cloth “duct tape” kind. $7 at Lowe’s.
Line the inside of the can with cardboard. This is important — your electronics should never touch the metal walls. I cut up an old Amazon box for mine. Wrap each electronic device in a cloth or put it in a cardboard box, then put it in the can. Put the lid on and seal every seam — lid to can, every edge — with the aluminum tape.
That’s it. That’s your Faraday cage.
Is it as good as a military-spec shielded room? No. Does it provide meaningful protection for the kinds of EMP scenarios we’re worried about? Every test I’ve seen says yes.
I keep two of these cans in my garage. One has communication gear, the other has miscellaneous electronics.
Electronics Must Not Touch Metal Inside a Faraday Cage
The protection only works if your devices are insulated from the metal walls of the cage — direct contact can actually conduct the pulse to the device. Line your trash can with cardboard, and wrap individual devices in cloth or put them in small cardboard boxes before placing them inside. This is the most common DIY Faraday cage mistake.
What to Put in Your Faraday Cage
Don’t just throw random electronics in there. Think about what you’d actually NEED if the grid went down for six months or more. If you’ve thought about emergency communication plans at all, some of this will sound familiar.
Communication:
- A Baofeng UV-5R ham radio ($25). Even if you’re not licensed, in an emergency the FCC isn’t going to come find you. But get licensed anyway — it’s free to study and the test is $15.
- A hand-crank/solar AM/FM/NOAA weather radio ($30). The Kaito KA500 is the one I use.
- A spare prepaid phone. Doesn’t matter if there’s no service — the GPS chip works without cell towers, the flashlight works, the calculator works, you can load maps on it.
Power:
- A small solar panel. I’ve got a Renogy 50W flexible panel ($85) rolled up in there. After an EMP, if your solar charge controller survives (or you have a spare in the cage), you can charge batteries.
- A solar charge controller. $15 PWM controller from Amazon.
- A USB battery bank. 20,000mAh or bigger.
- Rechargeable AA and AAA batteries plus a charger.
Information:
- A USB drive loaded with survival guides, first aid manuals, plant identification guides, your important documents, and family photos. All the information you normally access on your phone, but on a drive that works with any computer you can get running.
- I also keep a cheap Amazon Fire tablet ($50) loaded with Kindle books. Medical references, homesteading guides, that kind of thing. Knowledge is the one prep that weighs nothing.
Miscellaneous:
- A handheld GPS (Garmin eTrex). $130 but GPS satellites are hardened and would likely survive. Having navigation without cell service is big.
- LED flashlights and headlamps. I keep spares in the cage even though flashlights would probably survive an EMP anyway. Belt and suspenders.
Total investment for everything in both cans: about $450. Spread across two years of picking stuff up on sale.
The Bigger Problem Nobody Talks About
Here’s the thing that most EMP prep articles skip over completely. It’s not about your electronics. It’s about the GRID.
If the power grid goes down for six months — which is the realistic bad scenario — your Faraday cage full of gadgets is nice to have but it’s not what’s going to determine whether you make it or not.
What determines that is the same boring stuff that determines every other disaster scenario:
Water is the first problem, and it hits faster than most people expect. Municipal water systems run on electricity — pumps, pressure stations, treatment facilities. No grid, no water pressure. Within 24-48 hours in most cities, taps go dry. You need water storage and purification, same as any other grid-down scenario.
Your refrigerator is a box that stops working. Without power, you’ve got maybe 48 hours before everything in it is questionable. A chest freezer buys you 3-4 days if you stay out of it. After that, you’re eating pantry food and whatever you’ve stored. If you’re into homesteading and growing your own food, you’re ahead of most people already.
Security is the part that nobody loves talking about, but it’s real. Extended grid-down means desperation, and desperate people make different choices than comfortable people do. This isn’t Mad Max overnight — but after a few weeks of no power, communities that organized early consistently fare better than individuals who went it alone. This is less about defensive gear and more about relationships built before things go wrong.
Medical is often the highest-stakes gap in someone’s prep. Hospitals have backup generators, but generators run on diesel and diesel runs out. If you depend on medication — insulin, blood pressure, thyroid — a supply plan isn’t optional. If anyone in your family has regular medical needs, that’s priority one before anything else on this list.
Medical Dependency Is the Highest-Stakes EMP Gap
If anyone in your household requires daily medication — insulin, blood pressure drugs, thyroid medication — grid failure is a medical emergency on a timeline. Hospitals have backup generators, but those generators run on diesel that eventually runs out. Building a medication buffer supply with your doctor’s help is priority one before any other EMP preparation.
What I Actually Did (My EMP Prep Plan)
I’m not going to pretend I’ve got some perfect setup. But here’s the practical stuff I’ve done that applies to an EMP scenario AND about fifteen other disaster scenarios, which is the whole point. A solid emergency preparedness foundation covers most of what you need.
30 days of food and water for four people. Rice, beans, canned goods, freeze-dried stuff. Rotated annually. About $600 invested over two years.
Two Faraday cages with the communication and power gear I listed above. $450 over two years.
Hard copies of important information. Maps, contact info, medical info, insurance policies. In a binder. On paper. Sounds old-fashioned until the cloud doesn’t exist anymore.
The community piece is worth spelling out separately. I know my neighbors — not just their names, but their skills. There’s a retired nurse two doors down, a mechanic across the street, a guy on the corner who gardens like it’s his job. I have a pretty clear picture of which people on my block could actually contribute to collective survival. After two weeks without power, those relationships are worth more than any gadget in any Faraday cage.
Alternative cooking and heating. A propane camp stove with 8 cans of fuel, a rocket stove I built from cinder blocks, and a fire pit in the backyard with a grate over it. If you want to get serious about off-grid living, check out our complete off-grid guide.
Cash. $500 in small bills. ATMs don’t work without power. Credit cards don’t work without internet. Cash works until it doesn’t, and it works a lot longer than most people think.
The $89 Bags and Other Scams
Let me come back to those bags from the expo. EMP protection has become a cottage industry of fear, and there’s a lot of garbage out there.
“EMP-proof” bags that are just anti-static bags. Anti-static bags provide minimal shielding. They’re designed to prevent static discharge during shipping, not block an electromagnetic pulse. A galvanized trash can with aluminum tape outperforms them significantly.
“EMP-proof” generators. Some companies sell generators with “EMP hardening” for 3-4x the normal price. The hardening is usually just a metal enclosure. You could do the same thing with a regular generator stored in a metal shed.
“EMP shield” whole-house devices. These are surge protectors. Good surge protectors, in some cases, but surge protectors. They might help with the E3 component (which acts like a surge) but they won’t stop the E1 pulse from reaching your electronics. And they cost $300-400.
I’m not saying none of these products have value. Some do. But do your research before spending money, and understand that nobody — NOBODY — has tested these products against an actual nuclear EMP because we haven’t had one since 1962.
The Bottom Line
EMP is a real threat. Not a Hollywood fiction, not a zombie-apocalypse fantasy, but a genuine possibility that responsible people should think about.
But here’s what I want you to take away from this: 90% of EMP preparedness is the same as general disaster preparedness. Water, food, security, medical, community. If you’ve got those bases covered, adding EMP-specific protection is mostly just a couple of Faraday cages with some communication and power equipment inside.
Don’t let the fear merchants convince you that you need to spend $10,000 on specialized equipment. A $35 trash can and some common sense will get you further than most of what they’re selling.
And definitely don’t buy the $89 bags.
EMP preparedness is really just a layer on top of solid emergency preparedness. Get the basics right first — water, food, communication, medical — and the EMP-specific stuff is just a Faraday cage and some common sense on top.