When choosing the ideal cable and wire, the sheath material plays a particularly important role. It provides mechanical and environmental protection and contributes to the long-term reliable operation of cable products. Polyurethane (PUR) and polyvinyl chloride (PVC) are the two most commonly used sheathing materials for cables and wires. Although the difference is not apparent from the outside, they each have unique properties that make them suitable for different application scenarios. It’s often a matter of choosing between the two. Here, we’ll take a closer look at the performance characteristics of these two materials and discuss the application scenarios for which they are best suited.

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PUR Cable– Key Features

Polyurethane (PUR) is a commonly used cable sheathing material. It is an elastomeric material which means that they become soft and ductile upon heating and can be re-shaped when cooled. As compared to TPE cables, which belong to the same category of thermoplastic elastomers, PUR sheathed cables are more abrasion, cut and tear resistance qualities, and maintains good flexibility even at low temperatures. This makes PUR especially desirable for applications where dynamic flexing and bending are needed, for example, drag chains.

How to identify PUR control cables? When burned, they emit black smoke, have a blue flame, melt easily, emit a scorched smell, and have strong flammability.

PVC Cable– Key Features

PVC used to be the most widely produced general-purpose plastic in the world with an array of applications. It is widely utilized in construction materials, industrial products as well as household items. Meanwhile polyvinyl chloride (PVC) is a frequent cable sheathing material. It has good physical, mechanical and electrical properties, as well as good weather resistance and chemical stability, and can also be improved by adding different additives, such as flame retardant and heat resistant.

The advantage of PVC cable sheath is cheap, easy to process and install. It is commonly used in low-voltage cables, communication cables, building wires and more. However, PVC cable sheathing is relatively weak in terms of high temperature resistance, cold resistance and UV resistance, and it is not easy to recycle, which can easily cause environmental pollution.

How to recognize PVC material? When seen emitting a green light, a green flame can be seen alongside yellow flames rolling with white smoke emitting and having a hydrochloric acid scent.

Which Cable jacket Material Wins? PVC or PUR?

Feature Heat Resistance Halogen-free Mechanical Strength Abrasion Resistance Flexibility Oil Resistant UV Resistant Suitable for Wet Environments Flame Cost PUR Cable Jacket -40°C~125°C Practically halogen-free High Excellent High Excellent Excellent Good Excellent Higher PVC Cable Jacket -20°C~80°C Usually contains halogens Moderate Good Moderate Moderate Moderate Excellent Excellent Lower

• PUR vs. PVC in Durability

The material used for PUR jacket cables has the advantage of being resistant to oil and abrasion, whereas PVC is manufactured from a common material. At certain temperatures, the mechanical properties of the material are similar to those of rubber. PUR is also highly resistant to oil, solvents and UV radiation. In addition, depending on the composition of the material, PUR control cables are also halogen-free and flame-retardant, which is an important criterion for cables that are UL-approved and used in the U.S.A. PUR leads the way in terms of excellent abrasion resistance and toughness, and is particularly suited to applications that require a high degree of resistance to abrasion and mechanical stress.

PVC offers stable chemical resistance and good insulating properties. It is insoluble in water, alcohol and gasoline and has low gas and vapor permeability. Although stable in general environments, it is not as good as PUR in oil resistance and extreme temperature conditions.

• PUR vs. PVC in Varying Environments

When to use PUR cables?

1. Industrial Automation & Robotics: In industrial automation systems as well as in robotic applications, PUR jacket cables can withstand millions of bending cycles or strong torque without any problems.
2. Automotive: The automotive industry is very demanding and requires high temperature and oil resistant cables to connect sensors and control systems, PUR cables are the material of choice in automotive manufacturing due to their excellent physical properties.
3. Outdoor and Extreme Environment Cabling: The good weather resistance and low-temperature toughness of PUR cables make them appropriate for outdoor placement or use in extreme temperature conditions like security systems, building façade lighting, and remote monitoring equipment.

When to use PVC cables?

1. Residential and commercial building wiring: PVC cables are extremely common in electrical installations in homes, offices and commercial premises for power supply and lighting systems.
2. Fixed wiring and communication systems: PVC cables are suitable for indoor fixed wiring, including lines, low frequency data transmission and some simple communication networks.

We can clearly see the difference between the above applications in different environments. PUR cable is more suitable for outdoor or low-temperature operating environments. It is also suitable for applications with heavy oil contamination and the presence of specific chemicals. On the other hand, PVC is more suitable for indoor or non-extreme conditions, such as regular electrical wiring.

• PUR vs. PVC in Economic & Eco-Friendliness

PUR cables offer performance advantages, but are typically more expensive than PVC. The average price is 45 % higher than that of PVC. They are not suitable for low-cost, high-volume production.

PVC is a more economical option. However, recycling and disposal of PVC can be more challenging from an environmental standpoint. The best feature of PVC is that it is flame retardant and is widely used in fireproofing applications. However, PVC releases hydrogen chloride, chlorine gas and other toxic gases when heated above 148°C.

On the whole, when the price is one of the considerations then PVC cables are appropriate for conventional usages. PUR cables are suitable for more demanding industrial applications, where resistance to harsh conditions and longer service life are more important.

11 Questions to Ask Before Selecting a Multi-Conductor Cable

When it’s time to make an investment that will impact long-term business continuity, uptime, and effectiveness, you want to make sure you get it right. There’s little room for error or guesswork.

Like with many important product purchases, when it comes to purchasing multi-conductor cables, the trick is to find the right balance between cost and performance.

By learning as much as you can about these cables before you make a purchasing decision, you’ll avoid the hassle of discovering too late (likely during installation) that the solution you chose wasn’t the best option after all. This discovery can lead to rework and overspending, as well as system failure and unplanned downtime.

Not all multi-conductor cables are created equal. The decisions you make shouldn’t be based solely on price – your application and environment need to be considered, too. They’ll help you determine the type of cable construction and material you need for the results you want.

You’ll find multi-conductor cables in:

• Food and beverage manufacturing facilities, connecting things like machinery, robots, assembly lines, conveyor systems, and control systems
• Factories and mills, connecting equipment like furnaces, lighting, and thermal elements
• Machine tool manufacturing, supporting cranes and hoists, as well as conveyor and transport systems
• Automotive plants, used for processing equipment and tray wiring
• HVAC applications, controlling things like motor speeds and on/off settings for VFDs, pumps, and compressors

Because they’re used in so many applications – serving as control cables, VFD cables, robotics cables, and much more – multi-conductor cables are one of the most common types of cable around. They play a critical role in our daily connected communications.

Picking the Right Multi-Conductor Cable - Which Questions to Ask

How can you pinpoint the right multi-conductor cable for your application? First, consider your environment. Then, select a multi-conductor cable constructed for that setting. The four components that make up these cables – conductors, insulation, shielding, and jacketing – directly impact whether a cable will work in your plant or facility.

Before you make a purchasing decision, ask yourself these questions about your environment. Your answers will guide you to the right choice.

Always reference the cable’s maximum rated temperature (which is based largely on its materials of construction) and consider potential “over-temperature” conditions in your application.  Also be aware that many cable designs will have more than one “maximum temperature” depending upon the application, for example a PVC-insulated multi-conductor cable could be rated to 221°F (105°C) in stationary use, but only to 194°F (90°C) for flexible, motion-based applications.

2. Are chemicals, oils, lubricants, or machinery coolant present in your plant?

If so, then pay special attention to the cable’s jacketing. The right material will protect your cable from harsh liquids and chemicals.

Just because chemicals, oils, lubrication, and/or machinery coolant are common in factories and food and beverage environments doesn’t mean all multi-conductor cables are designed to withstand them. Their presence should factor into your cable selection.

If you want to learn more, please visit our website Polyvinyl Chloride Insulated Cables.

To maintain flexibility, multi-conductor cables contain plasticizers inside their insulating compounds. If these plasticizers come into contact with harsh chemicals, oils, or lubrications through absorption, cable degradation, performance failure, and potential downtime can occur. Once this happens, it can’t be undone.

A few examples of possible damage from exposure to chemicals or oils include:

• Swelling, which increases cable diameter
• Softening or melting, which leads to loss of cable flexibility and elongation
• Discoloration, which can eventually lead to cracking
• Hardening or cracking, which also leads to loss of cable flexibility and elongation

In these environments, it’s important to select a cable with a jacket designed to withstand these liquids, such as one made of polyurethane (PUR). It resists oils and chemicals better than other jacketing materials, including the commonly used polyvinyl chloride, or PVC (although PVC also has the ability to resist oil and acid in certain environments). 

4. Is moisture or humidity a possibility in your plant?

If cables will be used in wet environments – or in locations with high humidity – then corrosion may be a concern. Selecting the right conductor material can improve performance in these conditions.

Bare copper conductors are suitable in most of today’s industrial sites and are suitable for use in ultrasonic welding applications, but tinned copper (covered in metal alloy) is better suited for wet, high-humidity applications and are very easy to solder. Both offer similar performance, but tinned copper conductors will last longer in production and process environments.

5. Is fire a possibility in your environment?

If so, then you’ll need a cable jacket with a low smoke zero halogen (LSZH) classification. This type of thermoset jacket is suitable for installation in places where fire possibilities exist.

Lastly, low smoke zero halogen (LSZH) cables utilize jacketing materials that are safer when exposed to fire; they don’t produce as much dense smoke or highly toxic gases like non-LSZH cables, such as those with PVC jackets. If a cable with an LSZH classification encounters fire, fewer toxic fumes and less smoke will be emitted as it melts, keeping people and equipment safer.

6. Where will the cables be installed?

Are cables going into air-return (plenum) spaces? Below raised floors? If the installation involves a plenum or underfloor space, then the cable should be rated for that environment.

By selecting a cable rated for plenum spaces, you can rest easy knowing that the jacket and insulation materials allow safe operation with smoke and low-flame characteristics. Featuring high heat ratings and fire resistance, they can support technology such as signaling, sensors, security systems, HVAC equipment, and communications systems.

7. Is electrical noise present in your environment (and how much)?

Every environment experiences some amount of electrical noise (RFI or EMI), whether it’s from motors, lighting systems, wireless devices, two-way radios, or other cables. Very small amounts of interference are manageable, but noisy environments need shielded cables.

A shielded cable eliminates unwanted circuit noise through a metallic layer that prevents EMI and RFI from entering or emitting from the conductor. Without shielding, electrical noise may impact the cable’s performance, create crosstalk (interference), or impact the performance of equipment and electronics.

The type of cable shielding you select should be based on the type of electrical noise being generated in your environment. For example:

• Foil shielding is ideal for environments with high-frequency interference
• Braided shielding works best in environments with low- or medium-frequency interference
• Spiral shielding should be used only in environments with low-frequency interference
• Braided/foil shielding combines the benefits of both, making it very effective in extremely noisy environments (such as utility plants or heavy industrial sites)

In certain applications, multipair cable – a specific type of multi-conductor cable – can also be used to defend against noise. Their construction (insulated conductors twisted into pairs before being placed inside a jacket) is effective at preventing noise, crosstalk, and interference.

8. Is movement and automation (robots, cobots, conveying systems, etc.) present in your environment?

If your plant utilizes moving technology, then cable flexibility is crucial. Flexibility is impacted by all four components of the cable: the conductor, insulation, shield, and jacket.

If your application involves automation or movement (robots, moving gantries, etc.), however, then flexible cables will be needed to withstand bend. Look for cables with stranded conductors (multiple smaller strands grouped together) vs. one solid conductor.

Multi-conductor cables are available with different strand counts (the higher the strand count, the more flexible the cable). Determine upfront how much installation room is available – as well as what the cables will need to be installed around – and you’ll be able to accommodate the flexibility and bend radius requirements you need.

If you’re utilizing a shielded cable to control noise interference, some shield types are more flexible than others. While braid shields offer some flexibility, foil shields are even more flexible – but their ability to “flex” doesn’t last as long.

Insulation and jacketing material also impact flexibility, with some compounds having more than others. Silicone, for example, offers high levels of flexibility.

9. Will cable glands be used to secure your cable and provide strain relief?

10. How important is the installation speed for your project?

Are you in a hurry to get multi-conductor cables installed? Is there a deadline that needs to be met? If so, certain cable choices can be easier to handle and install than others.

If your project isn’t a rush job, then maybe speed isn’t a huge concern. But, if you’re on a tight timeline or have limited labor available, choosing the right multi-conductor cable can reduce installation time.

Consider tube extrusion cables, for example. They feature a tube jacket that’s faster and easier to strip as opposed to a pressure-extruded jacket. If you use automated cutting/stripping wire processing machines, this option can make the installation process go faster.

11. Are space constraints a factor (congested cable trays, narrow conduit, etc.)?

If you’re installing in tight spaces or small cable trays, then jacket and insulation thickness and weight can matter.

Learn More About Multi-Conductor Cables

Want to learn more about choosing the right multi-conductor cable for your environment and finding the right balance between price and performance? Contact Lapp Tannehill and we'll be happy to help you find the right cable for your needs. Reach us at 800.633. or chat with us online.

Browse Multi-Conductor Cables

Now that you know what to consider when selecting a multi-conductor cable, take a look through the multi-conductor cables that Lapp Tannehill offers. As a distributor, we have access to a variety of manufacturers to help you find what you need.

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