View A Video on Shielded Cable - A Quick Introduction
Shielded Cable
Electromagnetic interference is caused by the clashing of two different magnetic fields produced from the electric currents of two different objects. For example, an unprotected computer cord crossing paths with a bare telephone wire can cause EMI and damage one or both of the objects. The excessive amount of electrical appliances used in industrial and commercial environments, as well as in the consumer products contexts require
magnetic shields in a variety of forms. In the shielded cable category, two major styles dominate the market. Metallic foil is often used to cover cables. It is made from a fragile layer of copper or
aluminum and combined with a layer of linen for durability. The other common style of shielded cable is braided wire, usually produced from
copper. The way the copper wire is intertwined creates a mesh that has more holes then the foil, but is a sturdier covering. Both of these shields function by way of deflecting electric currents or redirecting them into the ground.
Certain areas are more sensitive to EMI then others, and therefore require both foil and braided wire shields at once. Whichever method is used, another important factor to ensuring the shields are working properly is that the cables are grounded. This simply means that they are attached to the ground in some fashion, so that the deflection of EMI can go into the earth instead of causing noise distraction or damage to objects as well as people, depending on the voltage involved. Power cables in particular carry high levels of voltage, and therefore can act as antennas and receivers for electromagnetic interference without the protection of shielded cables. EMI shields also guard against radio frequency interference, known as RFI. These sound waves can interrupt the productivity of other machines if not properly protected. Specific applications for shielded cables include microphones, musical instrument amps, computers, telephones, security systems, x-ray equipment and many more products charged by electricity.
