Allied Encyclopedia – Shielding vs. Armor

Shielding and Armor are often found side by side in Wire and Cable books and catalogs, and that makes it look like they’re practically the same thing. Both are metallic. Both are wrapped around cable components. Both protect the integrity of the cable. But although they have a lot in common, shielding and armor are not the same and the terms shouldn’t be used interchangeably.

So what makes them different?

Shielding is a layer of metal that falls between the part of the cable that passes electricity, also known as the conductor, and the outer layer of a cable, known as the jacket. Shielding is made of copper, aluminum foil, steel, or another conductive material. These materials work as “noise” insulation for the conductor, keeping the cable’s signal in and signals from other nearby cables out. It protects the cable from invisible signal and current interference, also called electrostatic interference. This allows the cable to work with uninterrupted signals, doing its job effectively and efficiently.

On the other hand, armor gives the cable physical protection. This layer of metal, also made of copper or aluminum, is wrapped around the outside of the cable. Armor is strong, sturdy, and defends the cable when it’s used in harsh environments such as those in commercial building or underground installations. The armor prevents the wire from being crushed, or otherwise physically damaged by the things around it. Though it may provide some blockage against interference, cable armor is not meant for use where physical protection is not needed.

While shielding and armor serve different and important purposes for cable, not all cables have both, or either of these components. Depending on the environment the product will be used in, the type of cable, and the function it is serving, a cable may not need the added strength of armor. If a cable is isolated or distanced from other sources of electrostatic signals, it may not need shielding either.