An electromagnetic pulse, or EMP, may sound harmless enough but its effects can be devastating.
An EMP is essentially an intense burst of energy (for instance a lightning bolt, which is simply a highly concentrated EMP event that is very localized) that, depending on size and intensity, could potentially wipe out electrical and information systems across vast areas.
EMPs can occur naturally, as with lightning and a case we will explore later in this article, as well as through man-made sources such as nuclear or radio-frequency (non-nuclear) weapons. In order to properly prepare for such a phenomenon – whether to defend against Mother Nature or technological warfare – it is imperative to have a clear understanding of what exactly an EMP is in order to properly prepare yourself to defend against it.
The following article will teach you the basics in understanding what an EMP is, how it can be caused, and the short and long term effects. This article also explores Faraday cages and how they can work to protect you against EMPs, discussing the features that are most important and various types you can purchase and build yourself.
- What is an EMP and How is it Caused?
- What is a Faraday Cage and Can it Protect Against EMPs?
- How Does a Faraday Cage Work?
- How Can You Test If Your Faraday Cages Works?
- How To Build a Faraday Cage
- How Effective are Faraday Cages?
- What You Need to Know About EMPs and Faraday Cages
- Further Reading
What is an EMP and How is it Caused?
An EMP – whether natural or man-made – is a burst of energy with the power to knock out electrical power. The lasting effects of an EMP can range from minor inconvenience to potentially sending the world back to a pre-communications technology ‘dark age,’ so to speak.
The largest man-made EMP threat looms from nuclear weapon detonation. In what is referred to as the Compton effect (named after physicist Arthur Compton who first theorized of the effect), the theory follows that when a nuclear bomb explodes, the explosion releases electromagnetic energy which binds to molecules in the atmosphere and releases bonded electrons.
These free electrons then interact with Earth’s natural magnetic field creating a current that is powerful enough to decimate electrical currents over a large expanse of area.
In 1997, Gary Smith, then the director of Applied Physics Lab at John Hopkins University, testified in front of the House National Security Committee that a nuclear detonation at 300 miles above the surface of the Earth could carry enough impact to knock out electrical power to the United States as well as most of Canada and Mexico (click here for source article).
However, nuclear weapons are not the only ones capable of generating an EMP; more localized sources of energy such as radio-frequency weapons or non-nuclear EMP devices can also wreak havoc.
Instead of drawing energy from a bomb explosion, these devices use concentrated microwave energy to cause disruptions in electronic equipment and destroy data. While these devices deliver a non-lethal pulse, the damage to electrical systems is no less devastating than with a nuclear detonation.
Naturally Occurring EMPs
In addition to lightning, EMPs can also occur naturally as a result of geomagnetic storms. While these occurrences are infrequent, a geomagnetic storm in 1921 affected the United States as well as parts of Europe for two days, closing the New York City railroad system and burning telegraph lines in Sweden.
The cause was later attributed to a group of sunspots that were 1.9 billion square miles in size. Today, a storm of this size would affect over 100 million people and cause widespread panic and chaos due to society’s heavy reliance on electronic devices for everyday life.
Despite the increased vulnerabilities present in modern times due to the prevalence of electronic devices in managing day-to-day activities, a future natural EMP event will likely come with advanced warning thanks to the benefit of space-monitoring stations.
A solar event would take hours, or even days, to reach Earth’s atmosphere, providing enough warning to safely stow electronics and turn off power systems (while shutting down power will not completely immunize systems against damage, it certainly can reduce the risk).
EMPs, regardless the source, have the potential to inflict immediate and long-term damage. Depending on the intensity of the pulse, EMPs can start electrical fires, incapacitate power grids, and shut down power sources for refrigeration (causing loss of food and medical supplies), water and sewage services, security systems, and phone and Internet (this would affect financial institutions and ATMs as well as land, sea and air transportation).
Additionally, any cars relying on high-tech computer systems (basically any model manufactured in the last 20 years) would be disabled and back-up generators could experience malfunctions or be ineffective if the existing equipment is damaged.
Recovery from an EMP is dependent on the size of the affected area and location, but could potentially take many years.
What is a Faraday Cage and Can it Protect Against EMPs?
The good news is, you can protect your electronic equipment from an EMP event. A popular method of EMP-proofing is to use a Faraday cage, a protective container equipped with a conductive outer layer that is typically made from aluminum.
A popular method of EMP-proofing is to use a Faraday cage, a protective container equipped with a conductive outer layer that is typically made from aluminum.
These containers function as a shield, protecting the electronic devices inside from EMPs. The term ‘cage’ originates from the fine metal mesh often used as a protective wall; however, research indicates that using a solid sheet of metal may be more effective (more on building your own faraday cage later on).
A Faraday cage can be built to any size to accommodate myriad manner of objects; keep in mind that an EMP can cause a voltage spike powerful enough to fry all manner of electronic devices, including cell phones, computers, radios, and appliances. The only must-have in constructing a Faraday cage is that it needs to be thoroughly lined by a conductive material with no gaps.
How Does a Faraday Cage Work?
The manner in which a Faraday cage can protect against an EMP is by using the conductive layer to diffuse energy rays (this is why it is imperative to have no openings through which energy waves can pass). The process is referred to as field cancellation, with ions in the conductive material realigning themselves to cancel the incoming electric field.
How Can You Test If Your Faraday Cages Works?
There is a very simple way to test the effectiveness of a Faraday cage: place a working cell phone in the cage and try calling it. A properly functioning Faraday cage will block the signal and the call will not go through.
How To Build a Faraday Cage
The best way to prepare yourself and your loved ones for an EMP is to prepare for the aftermath by ensuring you have adequate stockpiles of food, water, and other essentials. In the event of widespread electricity loss, store shelves will quickly empty and essential resources will become scarce.
Not only will having the supplies ready beforehand ensure you have enough to last, but also, in a worst-case scenario, there may be civil unrest or upheaval that makes it dangerous or impossible for you to leave your home, necessitating having sufficient supplies on hand. CLICK HERE to read The Bug Out Bag Guide’s comprehensive article on prepping for power grid failure.
In addition to preparing for the aftermath, having a Faraday cage built and ready to go is a measure you may choose to take to protect your household devices in the case of an EMP.
Homemade Faraday Cages for Large Devices
To protect your larger devices – including computers, televisions, tablets and appliances – a large ‘shield room’ can be fashioned by lining a closet with heavy-duty aluminum foil. When constructing your shield room, be sure to pay careful attention to how your foil is placed around the door frame so that it provides a continuous shield.
Laying a piece of cardboard on the floor as you load items into the closet can help prevent damaging the foil. Additionally, check for any outlets in the closet and ensure nothing is plugged into them and that they are also covered with foil.
If you don’t have a closet ready to go, or are prepping a location that is not in a home, you can build a freestanding Faraday cage by framing a box with 2x4s and then lining the outside with fine, conductive mesh. Remember, the openings on the mesh must be small enough to prevent energy waves from entering.
In place of mesh, you can also use sheets of aluminum or copper for your shielding material. Whatever material you choose, ensure its coverage is continuous over the entire exterior of your cage, or else its shielding effects will be rendered useless.
Homemade Faraday Cages for Small Devices
For smaller devices, something as simple as a shoe box lined with heavy-duty aluminum foil can do the trick. Alternatively, you can wrap your devices in several layers of foil, which also functions as an effective means of protection.
If you are considering building your own Faraday cage, make sure to check out this article and other resources with detailed building instructions.
Purchasing a Faraday Cage
You may already have a store bought Faraday cage ready to go and not even be aware of it – your microwave oven. While most people are familiar with their microwave’s ability to keep radiation in, few are aware that a microwave can also keep radiation out. To test your microwave’s effectiveness, unplug it (this is an essential first step, do NOT attempt this exercise while the microwave is plugged in) and run the cell phone test discussed in the previous section, How Can the Efficacy of Faraday Cages Be Tested?
There are also anti-static bags, available in a variety of sizes, that can protect against electrostatic discharge and are easy to store in your get home bag.
How Effective are Faraday Cages?
The effectiveness of your Faraday cage in protecting your devices against an EMP is dependent on a number of factors, including the origin of the EMP, how far your Faraday cage is from the EMP, and the type of rays emitted by the EMP.
High-frequency waves require smaller holes in the meshing while short-range EMPs contain gamma rays and X-rays that cannot be blocked by only a single layer of heavy-duty foil. To fully protect against EMPs from radiofrequency weapons, thick sheets of metal are required.
What You Need to Know About EMPs and Faraday Cages
In today’s technology-enabled world, it is easy to imagine the devastating consequences that could arise from a prolonged loss of power. A larger EMP that destroys power for several weeks, or even months, could easily lead to civil unrest and throw many first world residents into a survival situation.
While Faraday cages provide an effective means of first-line defense against EMPs, remember there may be little to no warning before a strike and you may not have the opportunity to put your Faraday cage to use. The best way to prepare for an EMP event is to prep yourself and your family for the aftermath, ensuring your stockpile of supplies will be adequate to see you through a potentially long-term spell of power-free living.
- Check out our article on Preparing Your Home For A Blackout
- Watch this video from Blackout USA: Click HERE To Watch Now
Are you fully prepared in the event of power grid failure? What must-have items have you stored away in case of power failure? Are Faraday cages part of your overall prepping strategy? Do you know of any other means to protect against EMPs? Share your thoughts in the Comments section below, thanks!