Understanding UL Ratings for Cable Insulating Materials

Several Underwriter Laboratory Standards (UL) ensure the safety of common insulation materials. Let's look into them in more detail.

UL 44: Standard for Thermoset-Insulated Wires and Cables

This is the standard for thermoset applications, covering power and lighting circuits It sets requirements for insulating materials' physical, electrical, and flame-retardant properties Most popular insulators that comply with UL 44 are XLPE, EPR, silicone rubber, PUR, and neoprene.

UL 83: Standard for Thermoplastic-Insulated Wires and Cables

The standard for thermoplastic insulations in general-purpose electrical wiring applications

Insulations that comply with the standards outlined in this requirement include PVC, PE, PP, TPE.

UL 758: Standard for Appliance Wiring Materials (AWM)

Сovers insulation materials used in appliance wiring, including flexible cords and cables It ensures that cables perform well and are safe in appliances The standard focuses on temperature rating, and flame resistance, among other factors. The standard must be met by thermoset, thermoplastic, and fluoropolymer insulations.

UL 83A: Standard for Thermoplastic-Insulated Underground Feeder and Branch Circuit Cables

UL 83A applies to thermoplastic-insulated underground feeder and branch circuit cables used in residential and commercial applications. The cables that fit these requirements are resistant to UV and moisture Many popular insulators fit these standards, including PVC and PE

UL 1277: Standard for Electrical Power and Control Tray Cables

UL 1277 covers electrical power and control cables installed in cable trays or raceways Fitting insulators include PVC, XLPE, and EPR The materials are expected to resist moisture, sunlight, oil, chemicals, and other factors that cables may encounter in cable trays or raceways.

UL 1441: Standard for Systems of Insulating Materials

- General

UL 1441 provides general requirements for systems of insulation materials, such as those used in motors, transformers, or other electrical equipment. It covers factors such as electrical properties, thermal aging, moisture resistance, and flame resistance. Fitting materials include PVC, PI, and Mica

CHAPTER VI

Thermoplastic Materials Compared

In this table, we compare thermoplastic materials based on their most important properties that contribute to different aspects of their performance.

CHAPTER VII

Thermoset Materials Compared

In this table, we compare thermoset materials based on their most important properties that contribute to different aspects of their performance.

Chapter Ix

Insulation Materials Ranking System

The three tables below grade thermoplastic, thermoset, and fluoropolymer materials based on the high school grading system to illustrate how different insulators compare to each other in terms of performance. In this grading, A+ stands for exceptional, A for excellent, B for great, C for adequate, D for below average, and F for poor.

Pricing is assigned the number, where 1 stands for the cheapest and most readily available insulation, while 5 stands for the most expensive one. Insulations are then assigned an average grade, where A+ = 4.0, A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0.

These tables are only for educational purposes, and do not represent an objective score. Depending on the applications, insulating materials might have different requirements, which would deem some factors more important than the others.

CHAPTER X

Thermoplastic Insulation Comparable Table Graded

CHAPTER XI

Thermoset Insulations Comparable Table Graded

CHAPTER XIII

Biodegradable Cable Insulation Materials

Biodegradable cable insulations are being developed in the 21st century because of the need to reduce environmental impact, improve safety, and contribute to the improved waste management cycle.

As it stands in 2023, no biodegradable cable insulations are effective enough to be used on a mainstream level.

Here are some of the insulations that are currently in development:

Polylactic Acid (PLA): PLA is a biodegradable thermoplastic monomer derived from renewable resources such as corn starch or sugar cane. It is commonly used in packaging and biomedical devices. However, its application in the field of electrical insulation still needs to be studied due to issues like moisture absorption and lower temperature resistance compared to traditional insulation materials.

As it stands right now, polylactic acid demonstrates good insulation properties at temperatures between room and 70°C. For higher temperatures, PLA does not prove to be an effective insulator at higher temperatures, as suggested by research. Despite this, PLA demonstrates good electrical properties compared to its petroleum counterparts.

Thermoplastic Starch (TPS): TPS is produced by destructuring starch under heat and shear in the presence of plasticizers like water and glycerol It's a fully biodegradable and renewable material The negative side of the material is that it has limitations in terms of moisture resistance and thermal stability, which make it less suitable for use in highperformance electrical applications

Polyhydroxyalkanoates (PHAs): PHAs are polyesters produced by bacterial fermentation of sugar or lipids in nature. They are fully biodegradable and are used in packaging, medicine, and agriculture. However, their cost and performance characteristics, such as long downtime for polymer recovery, have limited their use.

Bio-based Polyethylene (bio-PE) and Bio-Polyamides (bioPA): Bio-PE is similar to conventional PE but is made from renewable raw materials such as sugarcane. Likewise, biopolyamides bio-PA reflect the properties of bio-nylon. While it's technically not biodegradable, it is recyclable and has a lower carbon footprint compared to conventional PE. The strength of this type of insulation is that it is the most similar in properties compared to traditional types of insulation.

Materials like bio-PE and bio-PA have the most potential as long as their biodegradability can be improved because their physical properties are the closest to those of their petroleum counterparts

So far, biodegradable materials are far from achieving mainstream status because more research, testing, and development is required

As far as sustainability, the materials that are easily recyclable are the best in terms of environmental impact because recyclability is easier to achieve These materials include PE, Nylon, and PP, among others Most recyclable materials are thermoplastics, even though PVC, the most popular thermoplastic, is not recyclable

Conclusion

With the abundance of various insulating materials on the market, there is a coverage for any kind of application/cable in residential, commercial, and industrial applications of any complexity. In the future, we will see new types of insulations and improved/ optimized types of existing insulating materials. The developers of cable insulations will be looking into improving flame retardance, high-temperature resistance, and environmental sustainability. With existing insulations, like the highly popular PVC, the experts will be looking at optimizing the formulation electrical, thermal, and mechanical properties. This includes using heat stabilizers and flame retardants to improve its performance at high temperatures in fire-prone environments, and improving its photostability with additives. Improving recycling properties of the PVC insulation.