Shielding and Armor are often found side by side in Wire and Cable catalogs, which makes it look like they're practically the same thing. Both are metallic, wrapped around cable components, and protect the integrity of the cable. 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?
What is Wire Shielding?
Shielding is a layer of metal between the part of the cable that passes electricity, also known as the conductor, and the outer layer of a cable is 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 nearby cables out. It protects the cable from an invisible signal and current interference called electrostatic interference. This allows the cable to work with uninterrupted signals, doing its job effectively and efficiently.
What are Common Types of Wire Shielding?
Common types of wire shielding include foil shielding, made from aluminum or copper foil, which offers 100% coverage and is highly effective at high frequencies. Braided shielding, consisting of woven wire strands, provides flexibility and durability, making it effective at low frequencies. Spiral shielding, with wire spirals wrapped around the conductor, ensures good flexibility and is effective at audio frequencies. Combination shielding, which merges foil and braided shielding, delivers enhanced protection across a broad frequency range, combining the benefits of both types to ensure robust shielding in various applications.
What is Cable Armor?
Armor refers to the use of a protective outer layer that shields cables from mechanical damage. It is essential in harsh environments where physical protection is a priority. This layer of metal, also made of copper or aluminum, is wrapped around the outside of the cable. The armor is strong, sturdy, and defends the cable when it’s used in harsh environments, like those in commercial buildings or underground installations. The armor prevents the wire from being crushed or otherwise physically damaged in its environment. Though it may provide some blockage against interference, cable armor is not meant for use where physical protection is not needed.
What are Common Types of Cable Armor?
Common types of cable armor include interlocked armor, which is crafted from metal strips interlocked to form a tube, offering flexibility and excellent mechanical protection. Continuous armor, featuring a seamless metal sheath, provides superior protection against moisture and mechanical damage. Corrugated armor utilizes corrugated metal, delivering both strength and flexibility, making it ideal for direct burial and industrial applications. Braid armor consists of woven metal strands, striking a balance between flexibility and protection against abrasion and impact. Each type of armor is designed to enhance the durability and resilience of cables in various demanding environments.
What are the Differences Between Shielding and Armor?
Shielding and armor serve distinct purposes for cable protection. Shielding blocks electromagnetic interference (EMI), ensuring signal integrity in environments with electrical noise. Armor, on the other hand, provides mechanical protection against physical damage, making it ideal for harsh conditions. Not all cables require both; the necessity depends on the application's environmental demands and the cable's function. A cable may not need armor if it isn't exposed to physical threats, and it may not require shielding if it is isolated from sources of EMI.