Armor in the cable construction is used as physical or mechanical protection so that the cable wouldn’t damage from harsh mechanical impact. The choices of armor are Steel Wire Armored (SWA), Steel Wire Braid (SWB), and Steel Tape Armored (STA). The armor of the cable shall be galvanized (zinc-coated) to prevent the rust. The armor will be Galvanized Steel Wire Armored (GSWA), Galvanized Steel Wire Braid (GSWB), and Galvanized Steel Tape Armored (GSTA).
Instrumentation cables as per IEC 60092-350 shall use the GSWB type while the other two (GSWA & GSTA) are used for power cable. GSWB are more preferred for instrumentation cable because it’s more flexible than the others. Flexibility of instrumentation cable is needed to reach every single instrument in all area, events in the tight place. However, the type of armor that shall use in the particular project shall follow the client preference as per their experience.
There is also copper armor as optional choice. But since typical instrument cable have been equipped with the electrostatic screen that have copper drain wire, the utilizing of copper armor is not necessary (since copper armor may also used as electrostatic screen at the same time). Beside that, the steel wire armor have higher tensile strength rather than copper armor, therefore steel wire is more preferred to give the mechanical protection to cable.
Read More at: Armor of Instrumentation Cables | InstrEng
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