What is a Faraday Cage?

lightning-659917_960_720[1]A Faraday cage or Faraday shield is an enclosure formed by conducting material or by a mesh of such material. Such an enclosure blocks external static and non-static electric fields. Faraday cages are named after the English scientist Michael Faraday, who invented them in 1836. An impressive demonstration of the Faraday cage effect is that of an aircraft being struck by lightning. This happens frequently, but does not harm the plane or passengers. The metal body of the aircraft protects the interior. For the same reason, a car may be a safe place to be in a thunderstorm.

37150CircuitBoard

Protektive Pak Impregnated Corrugated Box with lid

ESD control products that provide a Faraday Cage or shielding include Statshield® Metal-In and Metal-Out Shielding Bags, Protektive Pak™ impregnated corrugated with shielding layer when using a lid, and Conductive Totes. Statshield® ESD Smocks creates a Faraday Cage effect around the torso and arms of the operator and shields charges from the operator’s clothing from damaging ESD sensitive devices. (Technically, suppressing the electrical field from clothing worn underneath).

 

 

There are standard tests measuring the energy penetration of electrostatic discharges to the interior. The Shielding test method per Packaging standard ANSI/ESD S541 is ANSI/ESD STM11.31 and the required limit is less than 50 nanoJoules of energy.

ESD shielding packaging is to be used particularly when transporting or storing ESD sensitive items outside an ESD Protected Area. Per Packaging standard ANSI/ESD S541 section 6.2 Outside an EPA “Transportation of sensitive products outside of an EPA shall require packaging that provides:

  1. Low charge generation.
  2. Dissipative or conductive materials for intimate contact.
  3. A structure that provides electrostatic discharge shielding.”

Definitions from the ESD Association Glossary ESD ADV1.0 include: Faraday cage “A conductive enclosure that attenuates a stationary electrostatic field.”

Electrostatic discharge (ESD) shield “A barrier or enclosure that limits the passage of current and attenuates an electromagnetic field resulting from an electrostatic discharge.”

Electrostatic shield “A barrier or enclosure that limits the penetration of an electrostatic field.”

Note: the ESD Association sells most documents, however, the Packaging standard ANSI/ESD S541 and the Glossary ESD ADV1.0 are free downloads from www.ESDA.org (click Standards and then Documents, scroll down to find documents that can be downloaded at no charge).

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About Protektive Pak

Protektive Pak is a leading manufacturer of ESD Material Handling and Packaging solutions. We offer a complete line of ESD Packaging products for transporting, storing and shipping of static sensitive assemblies. Our products include Storage Containers, Circuit Board Shippers, Open Bin boxes, Reel Storage Containers, Trays, Foam, Tape, Shielding Bags and much more! We also have custom manufacturing capabilities to your meet your special needs, including Thermoforming requirements. Protektive Pak offers a unique “Impregnated” corrugated material that provides greater durability than “painted” corrugated material. The buried shielding layer protects ESD sensitive items (ESDS) and minimizes sloughing and rub-off contamination. We also offer Plastek Industrial Fluted Plastic, an economical alternative to injection molded products and ideal for use where corrugated and /or paper products cannot be used. For further information, please visit our website at www.ProtektivePak.com

Posted on August 9, 2016, in ANSI/ESD S20.20, Articles, ESD Bags, ESD Control Boxes, ESD Education, ESD Information, Faraday Cage, Uncategorized and tagged , , , , . Bookmark the permalink. Leave a comment.

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