Can a Faraday Cage Stop an EMP?

Can a Faraday Cage Stop an EMP

If you have heard about electromagnetic pulse, you should know its devastating effects on electronics and electrical gadgets. How then can you protect your appliances against an EMP? Read on for more details.

A Faraday cage can stop an EMF from damaging your electronics and gadgets as long as they are inside the Faraday cage. A Faraday cage provides effective protection against an EMP and its destructive effect on gadgets and electronics. It does this through a process called field cancellation.

If you are new to the concept of electromagnetic pulse and its effect on electronics, this article is for you. If you are not new to the concept but are seeking information on an effective means of protecting your gadgets against its dangers, this article is also for you.

What Are EMPs?

The first step in understanding whether Faraday cages can stop an EMP is to determine the nature of an EMP. 

An EMP is gotten from a nuclear explosion. This pulse combines the characteristics of both electrical and magnetic waves and has the ability to move fast and cover huge distances in seconds.

In a nuclear reaction, there are many products. These products range from chemical components to lights of massive intensity, fire, blast waves and many more. While the aforementioned products are well-known as products of a nuclear reaction/explosion, there are other products that are not popular.  

One of these products is an EMP. An electromagnetic pulse is also known as EMP; it is a form of electromagnetic energy produced in a nuclear explosion or detonation. However, it should not be taken that an EMP is only produced during nuclear explosions. While nuclear explosion represents the man-made source of EMP, there are natural sources too. 

There are traces of EMP in the atmosphere after lightning strikes. This is why electronics get destroyed some times when the lightning strikes.

Generally, EMPs are invisible and very fast. When they come from strong nuclear explosions, EMPs can cover a wide area, as large as a continent. It is also very destructive as it can damage electrical systems and telecommunication infrastructures.

Components of EMP

EMP is a combination of two types of field, the electrical and magnetic. Due to these multiple fields, the EMP has different components. There are three components of an EMP. These include E1, E2, and E3.


E1 is a short but powerful electromagnetic field. It is the most important component of the electromagnetic pulse. The E1 component features a great speed and destructive capabilities. Because of these destructive capabilities, this component is the part of an EMP that is responsible for the destruction of electrical appliances.

This destruction is caused as a result of high voltage induced by this component of the EMP. This high voltage then causes an electrical voltage breakdown, thus destroying the electrical appliances. 

The action of the E1 explained above destroys electronics and electrical appliances. While the EMP has the capability to destroy computers and telecoms infrastructure, it does this through a different process.

The rapidly changing nature of the E1 component is responsible for its destruction of computers and telecoms gadgets. The rapid rate of change is so high that surge protectors in these equipment cannot defend against it. 

E1 is produced through a process known as the Compton Effect. This occurs when the gamma radiation produced in a nuclear explosion ionizes. This ionization occurs when the gamma radiation strips electrons from atoms in the atmosphere. When this happens, a current, known as Compton Current, is formed.

This current, or more appropriately, the electrons stripped from atoms in the atmosphere then travel towards the earth’s surface at a very fast speed. This speed is calculated to be as high as 90% of the speed of light. The speed of these electrons allows the magnetic field of the earth to interact with it.

This interaction gives rise to a pulse. Thus, E1 is produced.


The E2 is another component of EMP. It shares the speed characteristics of the E1 as it is fast and lasts between one microseconds to one second after its production. While E2 also has destructive capabilities, there are apparatuses that can protect devices and appliances against E2. However, there seems to be a problem in the protection against E2. 

E2 comes immediately after the E1 component in an EMP. As such, the apparatuses that should defend against the onslaught of the E2 component are destroyed already by the E1. Hence, there is usually very little protection that can be offered against E2 and its destructive capabilities.

E2 is produced by gamma rays and inelastic gammas that are generated by neutrons. It can also be induced during lightning. However, E2 that is produced by lightning is stronger and larger than that produced by a nuclear explosion.


E3 exhibits a marked difference from the last two components described. The component is the slowest of the three-component, lasting up to hundreds of seconds. It also has certain similarities to a geomagnetic storm caused by a solar flare, hence the name solar EMP.

This component is produced when the nuclear explosion occurs and distorts that magnetic field of the earth. It also has destructive tendencies, as it can destroy electrical components such as power line transformers.

These three are the components of an EMP. They constitute the destructive facets of the pulse and determine its characteristics.

How Does EMP Destroy Electronics?

Electromagnetic pulse affects electronics by causing high voltages in electrical appliances and voltages. Damage is then caused in electronics when this high voltage is induced, causing an electrical voltage breakdown.  

Apart from electronics and electrical appliances, EMP can also destroy computers and telecommunication infrastructures. It does this through its rapidly changing nature. It changes so fast that surge protectors in computers and pieces of telecom equipment cannot provide enough protection against its surge.

Hence, it is the high voltage caused by EMP and its rapidly changing nature that damages electronics and telecom infrastructures.

Will an EMP destroy electronics that are off?

Turning electronic gadgets off will not save them from the destructive effects of EMP. An EMP can be likened to a source of energy that induces an electric current in electrical gadgets and devices. Hence, the only way to provide effective protection to an electronic device against an EMP is to place it in a faraday cage. A faraday cage will isolate the device completely from the EMP, thus protecting it.

However, when an electrical appliance is turned off when an EMP passes through, it may reduce the intensity of damage that happens to the device. The reason for this is not far fetched. Turning an electrical gadget off separates it from an external electrical grid.

This means that while the EMP passes through the grid, through to the subsystems and components, the EMP will not be able to pass through to the gadget easily as there will still be some form of resistance. However, this is still not enough to protect that gadget from the destruction of the EMP.

Will an EMP destroy electronics that are off

How Does an EMP Affect Electronics That are Turned Off?

When you turn electronics off, they are cut off from the external grid. But this cut-off is not total. Some gadgets and devices, such as a computer, still draw electricity even when turned off. Thus, an approaching EMP can still affect such gadgets, although it will be minimal.

The only exception to this is when you completely disconnect such appliances from their wires, providing a faraday cage.

Moreover, electrical conductors are just one of the numerous ways an EMP can affect a gadget. This means that by turning electronics off, you have provided fractional protection for them against EMP. There are other ways through which an EMP can destroy electronics.

One of the common ways is through electromagnetic induction. A short but powerful electromagnetic force, such as an EMP, will induce momentary electric current in the electronic devices that they pass through. This momentary electric current could be induced at high voltages, thus destroying the gadget even when turned off.

What Is a Faraday Cage?

A Faraday cage is a shield that assists with protecting things, both static and non-static, from electromagnetic fields. They can be developed from the assembly of conductive material or a consistent covering of conductive material. Their size and configuration vary as they can be as large as a microwave or a steel fence.

Despite its size or structure, a faraday shield takes electrostatic charges or certain electromagnetic radiation types and disperses them over its surface.

Inventing Faraday Cage

Michael Faraday, a researcher during the 1800s, concocted the idea of a Faraday cage. While investigating electricity and power, Faraday found that when an electric transmitter, for example, a metal enclosure, is charged, it typically displays the charge on its surface alone and has no impact on the channel’s inner part. He chose to set up this reality on an investigation of a bigger scope, and in 1836, he thought of this experiment.

During the analysis, Faraday lined a room in metal foil and passed a high-voltage release from an electrostatic generator to the room’s outer part. From that point forward, he utilized an electroscope, a gadget used to detect electrical charges, to check for the presence of electric charges. As he had anticipated, the room had no hint of electrical flows, and just the outer aspect of the foil conducted the electric charges flowing through.

Faraday later led another trial to reaffirm his perceptions in his first examination – the ice bucket trial. This experiment included duplication of a prior one directed by Benjamin Franklin around 90 years back.

Benjamin Franklin’s trial

Benjamin Franklin allowed for a great advancement in the knowledge around the Faraday’s cage. In 1755, Franklin had watched Michael Faraday complete a similar experiment quite a while later, which provoked him to carry out his own test.

The trial: Franklin brought down an uncharged stopper ball holding tight a silk string into an electrically charged metal can, through an opening in the can.

Franklin noticed that “the plug was not pulled in to within the can as it would have been to the outside, and however it contacted the base, yet when drawn out it was not discovered to be zapped (charged) by that touch, as it would have been by contacting the outside.”

Besides, Franklin saw that the plug ball was influenced by the electrostatic charge on the can when it was hung close to the can’s exterior. It was promptly pulled towards the outside of the can. This situation ended up being a puzzle to Benjamin Franklin at that point.

Despite the fact that Benjamin Franklin found this marvel quite a long while before Michael Faraday, he couldn’t clarify it, leaving it to Michael Faraday to completely find.

How do Faraday Cages Work?

In basic terms, Faraday cages disperse electrostatic charges to the shield’s outer region, subsequently working as a shield to anything inside them. They go about as an empty conductor where the electromagnetic charge stays outside the cage.

Conductive materials can conduct electric charges because of the repository of free electrons they have. Faraday cages have a similar number of positive and negative charges coexisting when there is no electrical charge on conduits. Be that as it may, if an electrically charged item moves toward the cage from an external source, the positive and free negative particles will be isolated.

In the event that the approaching electrical charge is positive, electrons will swim towards it. This would leave the remainder of the cage without any negative charged electrons.

Then again, if the approaching object is negatively charged, positively charged particles swim towards it, leaving the remainder of the cage negatively charged. This cycle is alluded to as electrostatic induction, and it makes an electrical field that is inverse to that of the outside item. The cycle viably eliminates the outer electrical field over the enclosure.

How Does a Faraday Cage Stop EMP?

A faraday cage stops an EMP the same way that it works against radiofrequency, electromagnetic fields, and the rest. The only difference is that an EMP is several times stronger than a radiofrequency and EMF. Thus, a faraday cage does more work in trying to stop an EMP.

A faraday cage can stop an approaching EMP because of its materials. A faraday cage is made of conductive metals. Sue to their conductivity, they have numerous electrons on the outer shell of their atom nucleus.

When an EMP approaches the faraday cage, these surplus electrons will react. The electrons will leave locations with a higher electric potential to a point with lower electrical potential. This movement or rearrangement allows the electrons to interact with the approaching pulse and cancel out each other. This process is referred to as the field cancellation process.

It is important to note that a faraday cage must be without a hole or space for the approaching EMP to pass. This will nullify the effect of the whole faraday cage. You should also know that a faraday cage is as effective as the conductivity of the metal used to make it. This is why aluminum is the most used metal/material for the Faraday cage.

If you want to know whether a Faraday Cage can stop an EMP, check out my detailed article here.

Items That Do Not Need Faraday Cage Protection from EMP

Items That Do Not Need Faraday Cage Protection from EMP

It has already been established that an EMP can destroy electrical appliances and telecoms infrastructure. This destruction can render these equipment useless temporarily or permanently. However, it is important to note that there are many gadgets and items that are not affected by an EMP. As such, you do not need to place them in a faraday cage. Some of these items include;


Airplanes are usually not affected by the electromagnetic pulse from a nuclear explosion or lightning. This is because the electrons displaced by gamma-rays in the atmosphere travel downward and interact with the earth’s magnetic field at a much lower altitude. Thus, aircraft are usually not affected.


A car will most likely not be affected by an EMP because of the nature of its electric circuits and cables. The cables and circuits are usually very short and thus cannot induce most current from an EMP. Moreover, there is a metal frame that protects cars from an electromagnetic pulse.

In any case that an EMP does affect a car, its effect will be short-lived and very minimal.

Radiation from Domestic Appliances ...

Mobile Phones and Small Electronics

One of the distinctive nature of these types of gadgets is their short antennas. As a rule of thumb, the shorter the antenna or cable, the shorter the effect of EMP on such devices.

On Humans

While EMP induces a high voltage in electronics, this voltage will not flow to humans or animals; thus, they are safe against EMPs.


While EMP is not as popular as the other products of a lightning bolt or nuclear explosion, it is evident that it is also dangerous as it can affect the functioning of electronics and electrical gadgets. In some cases, these gadgets get destroyed and unusable. 

The use of a faraday cage remains one of the best means of protecting your gadgets from an EMP. Electrons on the outer shell of the cage will react with the approaching EMP to nullify it. 



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At the start, the aim of my research on EMF was to safeguard my family against the possible hazards of EMF radiation, but it has now become my mission to share this research with everyone. It is a fact that the threat of EMF is on the rise, but there are a number of ways by which we can protect ourselves.

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