Faraday Cages, Your Electronics, and EMPs

Homeowners have a number of concerns with household safety and protection. While many of these concerns reflect mundane life, some concerns reflect the global economy and the state of tension between world powers. With modern technology, a nuclear war is not the only global catastrophe we may face.

Electromagnetic pulses (EMPs) are bursts of electromagnetic radiation that can be caused by nuclear explosions or fluctuating magnetic fields. [Note: There is no current evidence that the government has technology capable of producing this effect without using nuclear devices.] The EMP effect can be produced by warheads detonated on the Earth’s surface or from detonations occurring high above the surface. The effects from these detonations will vary greatly depending on altitude and interaction with local magnetic fields.

EMPs will disable modern technology within a certain radius of the originating blast. Those caught in its path will have their cell phones, computers, cars, and household electronics cut out, and it will cut out the power grid as well. There are few ways at present to protect ourselves from this type of threat. One potential method of protecting your electronics and alternative energy sources is by using Faraday cages.

Faraday cages were discovered by Michael Faraday, and these devices can protect anything inside of them from electrostatic shocks (up to and including lightning) and from EMPs. They are generally built as metal cages with mesh on the outside, and they must be grounded. The metal mesh conducts the electricity or electromagnetic energy around the exterior surface of the cage, protecting the cage’s contents from harm, and the energy runs along the ground and dissipates. We use several examples of Faraday cages in everyday life: microwaves and coaxial cable. Each of these conducts energy around a particular surface to protect its contents.

While it is possible to protect numerous objects by placing them in these cages, homeowners must consider the utility of doing so. Protecting an outdoor generator by placing it inside a Faraday cage presents little impediment to daily life; in contrast, placing a television and stereo or game system inside a cage would make it difficult to use these appliances. It’s also not practical to place a stove or refrigerator inside a Faraday cage — you can plan ahead and replace your stove with a wood-burning or a propane/natural gas unit to avoid losing use of it due to an EMP incident.

It’s impossible at this point to protect energy sources such as solar panels from EMPs, but it may be possible to protect the generator components of wind turbines and hydro units. This depends on the individual unit construction, and whether it’s possible to have the generator itself be connected to the unit rather than be an interior component, which cannot be protected without shielding the entire device.

Numerous online resources exist that describe various Faraday cages and their applications. It’s possible for people to build cages using plans found on some of these sites. A homemade Faraday cage can be constructed simply by using a wood frame covered with metal mesh. However, a mesh with wide openings will not be useful for protection. The best sets of construction plans make use of a very fine mesh to ensure protection.

Please note that Faraday cages must be grounded in order to properly protect their contents. Some websites claim you can build cages from anything (including cardboard boxes and tin foil), but most of these will not work. Tin foil, while metallic, is not thick or strong enough to resist EMPs. You must have a solid structure, a metal mesh (not tin foil), and the cage must be grounded. Even the common Faraday cages mentioned earlier utilize grounding: coaxial cable contains a grounding wire, and all microwaves make use of three-pronged (grounded) plugs.

Faraday cages can offer excellent protection if properly constructed and grounded, so please be very cautious when reviewing instructions on how to build them. Make sure to select a comprehensive plan that includes and explains how the grounding works, and follow the specifications to the letter to ensure optimum protection for your appliances and electronics. Finally, avoid any plans that instruct you to use flimsy materials such as cardboard, as these will simply leave you unprotected.

One final note: a popular online myth is that cars are Faraday cages on wheels. While this may have been true to some extent when our vehicles were made out of more metal than anything else, this is no longer the case with vehicles that involve more fiberglass than steel. A car may ground some energy and offer slight protection from a lightning bolt, but it will not offer protection from an EMP. Do not rely on them to protect your small electronics (cell phones, laptops, etc.) from harm in the event of an EMP strike.

For Further Reading:

https://preparednesspro.wordpress.com/2009/06/18/emp-101-part-iv-faraday-cage/

https://www.disaster-survival-resources.com/faraday-cage.html