Here’s How to Build a Faraday Cage for Your Car
Probably the single most plausible, if not the most likely, mega-disaster facing the modern world today is that posed by an EMP. Specifically, any nuclear- or non-nuclear EMP has the potential to cause widespread, catastrophic damage to the power grid, electronics and any other technology that relies on electronic components.
The disruption might be temporary, there could be repairable damage or they might even be permanently destroyed.
Modern vehicles are thought to be highly vulnerable to the effects of an EMP because they rely on so many computers and electronic components even for basic functionality these days.
It’s a good idea to protect your daily driver, or a backup vehicle, from the effects of an EMP. You can do this relatively cheaply by building a Faraday cage to enclose your car when you aren’t driving it.
Keep reading and I will tell you how…
Table of Contents
What is an EMP?
An EMP is an electromagnetic pulse, a sudden, rapid burst of electromagnetic energy that can create dangerous surges of voltage in conductive materials and overload or burn out vulnerable systems.
Although these pulses happen everywhere, on a small scale, all the time in our increasingly electronic world, we’re specifically worried about major EMPs, the ones that can cause serious damage or disruption.
EMPs of this magnitude are typically thought to be created by the detonation of nuclear weapons as a secondary effect, specialty non-nuclear EMP generator weapons or even potentially natural but very powerful cosmic phenomena, specifically solar storms.
Wherever they come from, the effects of an EMP are the same; it is only the magnitude that is different.
What is a Faraday Cage?
A Faraday cage is a conductive enclosure, basically an EMP protective “envelope” that surrounds vulnerable devices, systems or vehicles and protects them from the effects of the EMP by conducting the energy away harmlessly before it reaches the protected item.
It is a fancy term for what is in actuality a very simple piece of gear.
There are multiple styles of Faraday cages, but they typically just take the form of a bag, box, larger container or even a room-sized enclosure made from conductive metal mesh or paneling.
So long as the enclosing material is solid or has very small gaps that will prevent EMP energy from penetrating and there are no large gaps or opening in the protective envelope, everything inside the cage should be safe from the event.
You Can Make a Faraday Cage Big Enough for a Car?
Yes. A Faraday cage is not the size of a pet crate or a jail cell: A Faraday cage is a concept, and, in theory, so long as it’s properly made from the correct materials with serious care to prevent failures, a Faraday cage can be as big as you need it to be.
A Faraday cage can be slightly larger than your vehicle and still afford protection, and it’s even possible to make a Faraday cage that is as big as a carport or garage.
Essential Factors for Success
Believe it or not, it is entirely possible to DIY an effective Faraday cage from readily available and relatively inexpensive materials, even if you are building one big enough for your car.
However, there are some essential factors that you must keep in mind if you want this project to stand any chance of success during a live EMP event.
The Cage Must Enclose all Six Sides of the Car
The key concept with a Faraday cage is that it must fully enclose the item being protected. This includes your car!
It is not enough to build a five-sided, box that you lower over your vehicle, open on the bottom: your Faraday cage must enclose your vehicle on all sides, the top and the bottom.
The Car Should Not Be Directly Touching the Cage
Also, your cage should be large enough that no part of your vehicle is touching the material of the cage, and preferably it has several inches of clearance on all sides except the bottom, obviously but we have a plan for that too.
The bodywork of pretty much every vehicle is conductive, and if the bodywork is touching the material of the cage the energy of the electromagnetic pulse will flow from one to the other, completely defeating the purpose of the cage.
Your Car Should Be Sitting on Something Insulating
It is easy to forget that the ground itself is a major conductor, and even if you have the car parked inside a garage, a carport or on a concrete pad the concrete or asphalt it is resting on is likewise conductive.
Considering the tremendous energy levels associated with a nearby EMP event, it is not out of the question that it can flow through the ground, through the tires and into the vehicle damaging its sensitive components.
There is some uncertainty regarding this factor, but all of the available evidence suggests at the bottom of the cage and your car should be resting on something insulating, be it a thick rubber mat or other material.
You’ll Need to Take Care to Reduce the Vulnerability of Your Garage, Too
If you do have your vehicle parked inside a garage, simple metal shed or partially enclosed carport should also do what you can to prevent EMP energy from penetrating the structure.
Any wiring, conduits, metal structural members and so forth can effectively transmit the EMP energy from the outside of the structure to the inside.
Yes, the Faraday cage should protect your car from an EMP in this way but you can further increase your protection factor by keeping the car in a properly-built Faraday cage, and also minimizing the amount of EMP energy that can penetrate the structure itself.
Depending on the design of a garage, in particular, this may be difficult or impossible, but do what you can.
What Material Should You Use for Your Faraday Cage?
Conductive metal is the very best one to use for a Faraday cage. The ideal choice of non-exotic available metals is silver, though it is going to be quite expensive for obvious reasons.
Copper is the next best, nearly as good, and much cheaper. If this is unavailable or you need to go cheap or still, aluminum should work fine.
Any can be a solid sheet or mesh at your preference, but if it is mesh it should have very small gaps between the wire, no more than a centimeter at most- and smaller is better.
Much bigger brains than mine have opined on the nominal wavelength, or different wavelengths, that a powerful EMP should be and calculated what size openings these waves are able to defeat, but the only sure factor is that smaller, fewer gaps are always better.
Whatever material you choose, it should be sturdy enough to handle and withstand regular handling, but not so thick that it is extremely expensive or extremely heavy.
As a benchmark, a common, heavy-duty metal screen door or patio mesh should be more than adequate for our purpose.
Building Your Faraday Cage, Step by Step
Now, with all that out of the way it’s time to get down to the business of designing and building our Faraday cage.
1. Measure Vehicle
The first thing you should do is measure your vehicle’s overall dimensions. Front to back, side to side, and top to bottom. This will inform you how large your Faraday cage needs to be.
Remember: we do not want any part of the vehicle to touch the cage, and a larger buffer zone is generally better. Add 6 inches, minimum, to all sides and the top measurement to account for this buffer, and if you have the room and the material leave more.
2. Place Insulating Material on Floor/Ground
With your dimensions determined, lay down an insulating pad for the vehicle and the bottom of the cage to rest on. Make sure you have enough surface area for all four tires to rest completely on it.
Note that a solid pad is better than individual contact “patches” because this will afford the bottom of the cage more support.
3. Lay Out “Floor” of Cage
Using whatever material you selected, lay down the bottom panel or floor of the cage over the insulating pad you put down.
Keep in mind, whatever material you choose must be durable enough to withstand the vehicle driving over it carefully without breaking. Breaches in the Faraday cage will allow EMP energy to enter it!
4. Measure Out and Cut Sides
Now, measure out the sides of the cage according to your measurements taken earlier. The left and right panel should be identical or nearly so, as should the front and rear panels.
If you were to put them together, and you will be, this would form an open-topped rectangle or square.
5. Measure Out and Cut Top of Cage
Now, cut out the top of the cage according to your measurements.
6. Build Frame, if Needed
Depending on the material you chose, you might need to build a frame to support your panels if they cannot support themselves.
You want to use a non-conductive material for the purpose, and preferably something that is lightweight and easy to handle. I like PVC pipe for the purpose.
You can get it over the counter cheaply and the components make it a snap to measure and connect in various ways to support the cage itself.
7. Attach Sides at Corners
With your panels cut and your frame constructed, if needed, it’s time to build the walls of the cage. The objective is for your conductive material to form one continuous envelope.
Depending on your skills and your available material, you could weld the pieces together, use adhesive, solder them, braze them or even tape them. What matters is that each side is seamlessly connected to the others.
Also, stop here and think about how you will place your car in the cage, or place the cage over your car. Are you going to drive the car in or push it in? You’ll need a way to remove the front or back side of the cage easily for the purpose.
If you’re going to lower the cage over the car with a hoist, you can connect all of the sides and the top and leave them as one piece.
8. Attach Top
With the sides built and connected, use the same method of attachment to connect the top. Make sure it is seamless on all edges. Remember, any sizeable gap could result in a failure!
9. Connect to Bottom, if Necessary
With the sides built according to your needs, and the top connected, think about how you’re going to connect this part of the cage to the bottom that is resting on your non-conductive pad.
If you are lowering the cage over the car when it is parked, you’ll need to make sure that the edges are touching on all sides securely one way or the other.
If you’re driving the car or pushing the car into the cage, you can go on and connect it to the bottom part now permanently or semi-permanently.
DIY EMP Protection is Achievable
And that’s it. You’ve constructed your own Faraday cage capable of protecting your vehicle from an EMP, or at least giving it better protection than it would have otherwise.
Just use the right materials, prepare the location, take your time, and ensure there are no gaps in the cage once it is closed.
Hopefully, you’ll be able to start your vehicle right up after the big one goes off!
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.