A cable’s performance, signal strength and distance are important traits when shopping for a cable. But the cable’s protective jacket is as crucial in determining the cable’s quality. The cable jacket protects it from the elements (moisture, UV, heat, fire) as well as from mechanical and chemical aspects. The jacket shields the conductors inside the cable.
That said it is important to choose a cable with the appropriate jacket for the installation at hand. This choice will affect the ease of installation and the longevity of the network. Especially when dealing with outdoor installations, but not exclusively.
Cable Jacket Characteristics
For exterior installations, in order to be able to deal with harsh environments (extreme heat or cold weather, moisture, etc.) a robust cable jacket is required. Most exterior application cables, for use above or below ground, are designed to withstand the elements to varying degrees depending on quality and cost.
The cable jacket material is the factor that makes the difference in protection performance. cable jacket characteristics to consider include:
• Approvals – Compliance with jurisdiction’s code per specific application
• Chemical Resistance – Life expectancy during exposure to chemicals
• Color – Mostly for identification and safety
• Elastic memory – Flexibility and handling, primarily in coil cords
• Flexibility – Affects the ease of installation and long-term flex life
• High-temperature resistance – Peak and ambient operating temperature
• Low-temperature flexibility – Suitability for arctic and harsh winter climates
• Surface texture – Ease of installation
Cable Jacket Types
There are multiple cable jacket materials. The jacket material / type selection changes per application and environment therefore it is crucial to have an understanding of the available cable jacket materials and their qualities.
• PE (Polyethylene) – PE has superior electrical properties with very high insulation resistance. It can be stiff and very hard, however low density PE (LDPE) is more flexible. PE has excellent moisture resistance. Additionally, properly formulated PE has outstanding weather resistance.
• PVC (Polyvinylchloride) – PVC can be designed to function in varying environments and applications. PVC is a low-cost material; it is flexible, fairly rugged, as well as flame/oil-resistant material. It can be produced in multiple finishes including matte, glossy and slick.
• PUR (Polyurethane) – PUR is very elastic, with a very high memory, facts that make it ideal for coil cord applications. It has superb flexibility in low-temperature environments, and performs well when exposed to oil and ozone. It is also abrasion resistant.
• Thermoplastic CPE (Chlorinated Polyethylene) – Chlorinated Polyethylene is commonly used in very harsh environments. It is very rigid, lightweight, with 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 it provides.
• TPR/TPE (Thermoplastic rubber/elastomer) – TPR/TPE has excellent low-temperature properties and it saves the cost of a thermoset material. It is quite flexible and has good chemical and oil resistance. Thermoplastic elastomer has good abrasion resistance and surface texture, but is not as rugged as PUR.
• Thermoset Polyolefins (CPE, CSPE, etc.) – The only truly melt resistant material specified here and in the same family of materials as natural rubber. Highly elastic with excellent memory. Thermoset Polyolefins is known of its ruggedness, low-temperature flexibility, UV stability and heat resistance.
Knowledge is power. Make the best choice per installation on your next job.