What is the Purpose of a Cable Jacket?
The cable jacket is the first line of moisture, mechanical, flame and chemical defense for a cable. More specifically, the jacket provides protection for the shielding and conductors within the cable. The jacket protects the cable from mechanical damage during and after installation. Cable jackets are not intended to replace internior cable reinforced armors, but they can provide a fairly high level yet limited means of protection. In addition, cable jackets also provide moisture, chemical, UV and ozone protection.
What Cable Jacket Characteristics Do You Need?
In most exterior applications, a physically robust cable jacket is needed because the environment may be harsh – either above or below ground – most cables are designed with this in mind. As always, there are varying levels of ruggedness available in the market, and you often get what you pay for.
Common cable jacket characteristics to consider when choosing an the cable that’s right for you are listed below:
|Cable Jacket Characteristic||Benefit of Characteristic|
|Flexibility||Ease of use and long-term flex life|
|Chemical resistance||Life expectancy during exposure to chemicals|
|Low-temperature flexibility||Suitability for arctic or winter climates|
|High-temperature survivability||Determines peak and ambient operating temperature and contributes to ampacity rating|
|Color||Identification, safety and appearance|
|Surface texture||Ease of handling and installation|
|Elastic memory||Flexibility and handling, especial in coil cords|
|Approvals/Compliance||Suitability for a given application/jurisdiction|
|Flame resistance||Safety and flame spread|
Types of Cable Jackets
There are many types of cable jackets available. It’s important to consider the jacket type when selecting the compatibility with the application’s connectors and environment. For example, an extremely cold environment may require cable jackets that remain flexible at very low temperatures.
The table below contains typical characteristics of some of the most common jacket types used both indoors and outdoors for most cables:
|Jacket Material||Use / Benefit of Jacket Material|
|Polyvinylchloride can be formulated to function in a variety of environments and applications. It is usually low-cost, flexible, fairly rugged, and a flame/oil-resistant material. PVC can be made in either a matte,glossy or slick finish. IMSA 19-1 has a PVC jacket|
|Excellent electrical properties with very high insulation resistance. Polyethylene can be stiff and very hard, however low density PE (LDPE) is more flexible. Moisture resistance is excellent. Properly formulated PE has excellent weather resistance. IMSA 20-1 has a PE jacket.|
|Polyurethane is very elastic, with a very high memory, which makes it ideal for coil cord applications. It is abrasion resistant, has excellent flexibility in low-temperature environments, and performs well when exposed to oil and ozone.|
|Thermoplastic elastomers have excellent low-temperature properties without spending the money needed for a thermoset material. It has good chemical and oil resistance and is also quite flexible. Good abrasion resistance and surface texture, but is not as rugged as PUR.|
|Generally used in very harsh environments. It is lightweight, very rigid, and has a mildly rough surface texture and a low coefficient of friction. It is low-cost relative to the level of oil, moisture, chemical and UV resistance provided.|
(CPE, CSPE, etc.)
|The only products in this list that are truly melt resistant and in the same family of materials as natural rubber. They are highly elastic with excellent memory. This material is known of its ruggedness, low-temperature flexibility, UV stability and heat resistance.|
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