Many cables have jackets for good measure. Much like the garments people wear, a jacket is an outermost layer that helps provide protection for the inner components of a cable. It specifically protects the insulation and conductor core of the cable. It serves as the first line of defense against abrasions, heat damage, moisture, flame, and chemical damage, just to name a few.
The jacket also protects the cable from mechanical damage during and after installation. Just like a suit jacket is usually worn for specific applications and athletic jackets as well, so too are cable jackets used. It is important to have the correct jacket present for each application.
The 3 Most Common Cable Jacket (Sheath) Materials
Many applications require unique characteristics and protection, so cable manufacturers offer a selection of jacket materials, also known as sheaths, that are produced from various material mixtures. Based upon the jacket (sheath) material chosen, this outer sheathing can have very different properties when facing external conditions and environments. Indoor cable applications will usually have unique characteristics compared to those used for outdoor applications.
For example, cables installed within a structure where high temperatures are present may require some type of heat or flame resistance property. Just much like a cable that needs to go underground will require direct burial compliance.
While there are many types of cable jackets, there are three that are highly used across all industries. Those three jackets (sheaths) are PVC, PUR, and TPE.
Here is an overview of the different types to help you choose the right cable jacket material.
Polyvinyl Chloride (PVC)
Polyvinyl Chloride (PVC) is a very versatile thermoplastic. PVC cable sheathing is popular because of its strong physical properties, like high strength and strong insulating properties. It can resist oils, acids, abrasions, sunlight, and heat. The material is also resistant to salt, water, and moisture.
Due to its chemical structure and flame resistance, it is often used within assembly lines, packaging, lighting technologies, and control cables. However, in the event of a fire, properties such as chlorine (a halogen) are released from a PVC cable, which can pose a danger to humans since they react with water. In the low voltage range (up to 1,000 V), PVC is also known as the material with the best price-to-performance ratio.
Polyurethane (PUR)
Polyurethane material (PUR) is a very elastic and self-extinguishing thermoplastic elastomer with great “memory” properties that make it ideal for retractile coil cords. These jackets have excellent oil, oxidation, and ozone resistance.
When formulated, they can also have good flame resistance properties. Two strengths of PUR sheath material are notch resistance and flexibility even at low temperatures. However, at high temperatures, PUR can become very rubber-like, leading to higher abrasion within the chain in contrast to the other two materials.
Due to their composition, they do not contain any toxic halogens (chlorine, fluorine, bromine, etc.) that could escape in the event of a fire. Halogens carry the risk of producing a toxic acid if combined with water after its release into the air.
Applications that will or potentially be exposed to fire should use halogen-free PUR cables. Cables sheathed with PUR are popular for sensor and control cables in plant construction, the food industry, the medical industry, cement plants, railways, and the automotive industry.
Thermoplastic Elastomers (TPE)
TPE materials are mainly used in applications that require durable flexible cables since they can withstand mechanical loads very well and have a high resistance to external influences, such as chemicals or temperatures.
TPE can withstand temperatures ranging from -35°C to +100°C and is also halogen-free. Halogen-free TPE cables are resistant to inorganic oils, organic oils, and deep freeze applications.
With the addition of flame retardants, TPE can also be classified as a flame retardant material, making it UL-compliant. TPE-sheathed cables are the most abrasion-resistant cables. TPE cables are used in both indoor and outdoor industrial applications.
They are used for large appliances, machines, motors, and lighting due to the amount of flexing likely to occur. TPE is often used in more robust applications that feature fast movements, such as conveyor systems and crane systems.
| Resistance to: | PVC | PUR | TPE |
|---|---|---|---|
| Oxidation | Excellent | Excellent | Outstanding |
| Heat | Good – Excellent | Excellent | Outstanding |
| Oil | Fair | Outstanding | Outstanding |
| Low Temperature Flexibility | Poor – Good | Excellent | Outstanding |
| Weather, Sun | Good – Excellent | Excellent | Outstanding |
| Ozone | Excellent | Excellent | Excellent |
| Abrasion | Fair – Good | Excellent | Excellent |
| Electrical Properties | Fair – Good | Excellent | Excellent |
| Flame | Excellent | Excellent | Outstanding |
| Nuclear Radiation | Fair | Excellent | Poor |
| Water | Good – Excellent | Good – Excellent | Excellent |
| Acid | Good – Excellent | Excellent | Excellent |
| Alkali | Good – Excellent | Excellent | Excellent |
| Gasoline | Poor | Excellent | Excellent |
| Benzol | Poor – Fair | Excellent | Excellent |
| Degreaser Solvents | Poor – Fair | Excellent | Excellent |
| Alcohol | Good – Excellent | Excellent | Excellent |
| Weld Slag | Fair | Excellent | Excellent |
*Czubek, J. (n.d.). Which cable jacket is best for your application? Automation Insights.
For all your PVC, PUR, and TPE cable needs, MISUMI features a full line-up of different jacketed cables suited to multiple applications. Explore the selection here.
