Instrumentation Cable armor, Types of Instrumentation cable armor

What is Instrumentation cable armor:

Armor is used as physical or mechanical protection in the cable building so that the cable is not damaged by severe mechanical effect.

In order to provide this protection, armor (generally a metal) is often applied over the cable core. The armor extends life, while enhancing the cable core’s reliability, safety, and efficiency. The following are some kinds of armor that are commonly used.


The armor options are Steel Wire Armored (SWA), Steel Wire Braid (SWB), and STA. To avoid rust, the cable’s armor shall be galvanized (zinc-coated). The armor will consist of Galvanized Steel Wire Armored (GSWA), Galvanized Steel Wire Braid (GSWB), Galvanized Steel Tape Armored (GSTA).

Instrumentation wires shall use the GSWB type in accordance with IEC 60092-350 while the other two (GSWA & GSTA) are used for energy wires. For instrumentation cable, GSWB is more preferred because it is more versatile than the others.

Copper armor is also available as an optional option. But since typical instrument cable has been fitted with an electrostatic screen with copper drain wire, it is not essential to use copper armor.

In addition, the steel wire armor has greater tensile power than the copper armor, which is why steel wire is preferred to provide the cable with mechanical protection.

Type of Armor:

Interlocked Armor:

Usually galvanized steel or aluminum is used in interlocked armor. Other metals, however, are sometimes used in specific applications. During and after installation, the interlocking structure protects the cable from harm. The armor can be introduced straight to the insulation or to an inner vest.

Continously Corrugated and Welded (CCW):

CCW armor consists of forming an aluminum strip along its length into a circle and then welding it to the seam. This soft pipe is then rolled or crimped in order to form ridges in order to avoid bending.

This type of sheath offers an impervious seal as well as physical protection against moisture and other chemicals.


Basket-weave armor is made of steel cables that form a braided exterior cover. Galvanized steel, aluminum or bronze cables may be used. This armor is usually used on shipboard wires as it offers the mechanical protection of an armored cable, but is much lighter in weight than other kinds of armored covers.