Reverse Engineering: Why you need it and when.

Do you need a wire or cable and have no idea what it is? You are not alone, it happens more times than not especially for equipment repairs, obsolete parts, and failure analysis. When do you need to have a cable reversed engineered? You may like a particular cable's performance or you have a piece of cable that you or your customer may want more of but don't know what it is or who manufactured it. Then reverse engineering is the answer. Who performs this service? Most custom wire and cable manufacturers can assist you.

Reverse engineering wire or cable is commonly performed to determine:

• Conductor stranding and material.
• Cable construction
• Insulation and jacket materials

Custom wire and cable manufacturers routinely reverse engineer wire and cable to identify the materials used and the cable construction. It is best to provide a sample between 1 to 2 feet if possible and keep in mind it will be dissected in the process.

Outer jacket
Reverse engineering wire and cable begins with measuring the outside diameter (OD) of the wire or cable. The longer the piece the better it is to obtain the nominal OD. The outer jacket is carefully removed to expose the core. Normally, cross sections are taken of the outer jacket to measure wall thickness. Jacket material is tested to identify the type of material used.

Braid, shield or tape
If there is a braid or shield the construction will be examined. The pitch, number of ends, material and coverage can be determined at this point. If there is a tape wrap present, the overlap, type of material and size will be examined.

Core construction
The next step is to examine the cabling construction. Once the shield and/or tape is removed the following can be determined: Cable lay or twists per inch, filler material used, the use of strength members, number of conductors and conductor color code.

Conductors
The conductor material, plating used (if any), gauge and conductor strand count and construction are checked. A cross section of the conductor will identify the wall thickness of the insulation and OD. At this point the insulation material will be identified.

Insulation and jacket materials
There are several ways to identify the materials used for insulation and jackets. The obvious is the look and feel of the insulation or cable jacket. Computer analysis and burn testing are also used. Plastics and rubber each have distinct characteristics when placed on a flame. Experienced engineers can determine the type of insulation material by whether it burns, melts, or self extinguishes. The odors produced when burned also are distinct to each type of material. Burn testing should only be done by experienced individuals in a controlled environment, gases can be toxic as well as the risk of fire is present.

Failure analysis
Failure analysis is another reason for reverse engineering wire and cable. When a cable fails, determining the cause can many times be done with reverse engineering to pinpoint the problem. Common problems with handheld devices with poor strain relief is damage to conductors or conductor stranding due to excessive bending. Shielding materials can over time damage conductor insulation. Dissecting the cable at the problem area can expose the problem. Custom wire and cable manufacturers can make material suggestions such as the use of higher conductor stranding or alloys, insulation materials or cable construction design alterations based on the findings of reverse engineering.