For users and buyers of enameled wire, ensuring the highest safety, reliability, and performance standards is crucial. Ensure you check if the wire is UL (Underwriters Laboratories) certified, as it is a key indicator of these qualities, offering assurance that enameled wires meet global safety and performance criteria. This mark determines that it is safe for industry performance and has undergone rigorous testing.
Wondering how to get the UL certification or what are the advantages of UL certification for enameled wire? If yes, then you are at the right place. In this blog, we will discuss the ins and outs of UL certification for enameled wire.
Understand Enameled Wire
Enameled wire, also known as magnet wire, is a type of copper or aluminum wire that is coated with a thin layer of insulation, typically made from enamel or other polymer materials.
The thin coating of insulating enamel helps in winding the wires into coils, which avoids any short circuits.
These wires come in various specifications, each suited for various electrical applications. It is widely used in energy, automotive, commercial, transportation, and other industries. Moreover, the uniform cover and high mechanical strength allow superior heat resistance against chemicals and solvents.
But, it can be difficult to test the authenticity of these enameled wires and understand their quality. Due to this, UL certification is used as an industry parameter to denote its safety and insulation.
Importance of UL Certification for Enameled Wire
Enameled wire is used in electrical applications like motors, fire and safety devices, electromagnets, and transformers. Many companies and brands offer self-proclaimed certifications, which are not trustworthy as they are all for marketing purposes. Unlike these certifications, UL is a third-party certification that helps maintain impartiality.
UL does not favour brands and uses multiple tests to determine the risks and industry concerns. Due to this fairness, UL is trusted globally by leading manufacturers for the performance and longevity of enameled wires. The following are the importance of having a UL certification for enameled wire:
● Complying with Market Regulations
Many industries and countries use UL certification as a legal requirement to enter the market. This ensures that the enameled wires are genuine and not of cheap quality. UL-certified wires can help in avoiding the risks of legal issues and hefty fines.
● Performance Guarantee
Cheap-quality enameled wires cannot handle demanding tasks and can fail prematurely, leading to accidents. UL certifications help save users’ excess effort, resulting in less downtime and reliable performance. This safeguards the investment of users and also increases the brand value of manufacturers.
● Safety Assurance
If the thermal capacity of the enameled wire is low, safety concerns may arise. To avoid such issue, UL uses testing of electrical safety, fire resistance, and resistance to environmental factors.
● Product Authenticity
There are various types of enameled wires on the market, all claiming to be the best. Buying UL-certified enameled wires helps consumers reduce the risk of investing in fake and low-quality products.
Tests Involved in UL Certification for Enameled Wire
For ensuring the highest safety standards, UL uses three main parameters in their test of enameled wires. These include temperature testing, electrical safety and material testing. UL determines if the enameled wire is safe for the end user based on the build quality, insulation, and durability. The following are four main tests determining the quality of an enameled wire per the UL standards:
1. Full Thermal Aging Test or One Temperature Thermal Aging Test
In this test, UL determines the ability of the enameled wire to withstand long durations of high temperatures. It is important to know that if the adhesive layer and self-bonding enamel coating have UL certification, then only one temperature test is done. If not, a three-temperature point aging test is necessary to meet industry standards.
This test involves three or more accelerated heating temperatures, known as “ three-point aging”. The test samples for aging are created by pairing enameled wires which comply with ASTM D2307 or NEMA 1000 standards. However, the force and number of twists are different depending on the wire diameter. For each aging test, a minimum of ten wire pairs are used.
These are mounted on a rack for high-temperature aging tests. These samples are placed in an oven for screening for the aging process. This continues until all ten pairs pass through each temperature point until the wire breaks down. This indicates the end of the aging test, after which detailed data analysis is done.
Each manufacturer can request a customised temperature rating based on their enameled wire. UL always uses a 20°C temperature point for low, medium and high temperatures. This helps in staying on the safer side and determining the full performance capabilities of the enameled wire.
Data Requirements for Three-Point Aging Test of Enameled Wire
As per the standards set by UL, the average logarithmic hours at a low temperature should not be less than 5000 hours. The average logarithmic hours at high temperatures should not lower than 100 hours. The test will be considered invalid if the correlation coefficient for three temperature points is less than 0.95.
How to Select a Single Temperature Point for Aging
As per the UL 1446 SB4.4, the temperature point for aging is selected through UL-approved wire enamel. Here, the aging time is closer to 1000 hours. If no test data is available for the specific wire enamel, then the temperature is based on the linear relation in the original test data.
However, this may result in a different temperature point. Once the data is selected, the aging starts on the original evaluation line. It is important to know that the correlation confection must be equal to or greater than 0.95 to pass the test.
2. Dielectric Strength Test
In this test, there are five pairs per test to determine the dielectric strength of enameled wire. UL applied a volvate rate of 500V/s till the breakdown voltage can be recorded. As per the NEMA MW1000 standard, various standards of dielectric strengths are specified. These are based on the diameter, film thickness, and type of enameled wire. This test is helpful in determining the wire’s ability to withstand electrical breakdown.
3. Elongation and Heat Shock Test
An enameled wire must be stretchable, as this helps in adding extra durability during higher temperatures. This test is designed to test the wire’s ability related to its mechanical properties. In this test, a sample is collected using three pieces of 254 mm enameled wires. This helps in deciding the thermal and tensile strength.
First, rapidly pull the enameled wire at a rate of 3.7-4.6 m/sec to the required elongation, then wrap the rapidly pulled sample onto the core rod, and then place the wrapped sample in the designated temperature oven for 30 minutes. The sample needs to be suspended in the oven. . Once this is done, the samples are removed from the oven to be checked for signs of cracks or peeled enamel film
In this test, the core’s diameter is usually three times that of the enameled wire. The designated temperature of the oven is set according to the temperature specified in the NEMA MW1000 standard for the ANSI type of enameled wire. This is mostly set at 20°C above the temperature rating to assess the ability of the enameled wire.
4. Infrared Analysis – IR
The infrared spectroscopic analysis test is done as per the UL746A, which only confirms the chemical composition of the enamel film, establishes the infrared spectrum and saves it for future use. Once the enameled wire is certified, annual follow-ups help in inspecting the random samples. This testing of the infrared spectrum is compared with the original reference during the initial certification. Both of these spectra must match to keep the UL certification.
In addition to infrared spectrum analysis, in the annual follow-up inspection service, two testes need to be done on the field drawn enameled wire: Insulation strength test and tensile and thermal shock test. In most cases, the thermal aging test is not required. The samples used in these tests are fully cured enameled wires. If the enameled wires are not completely cured, there are two risks: one is that it may affect the performance of aging testing during certification, and the other is that there may be differences in the spectra during subsequent follow-up inspection sampling.
Process of Getting UL Certification for Enameled Wires
If you want to get UL certification for your enameled wires, you can follow a simple process listed below:
- Application: You need to submit a detailed application to the UL authorities. This is a formality which requires complete information on enameled You can mention applications, specifications, materials or techniques used.
- Evaluation: After your application is approved, the UL engineers go through the factory facilities and the material specifications. This is an initial evaluation of your enameled
- Testing Phase: Once this initial evaluation is done, your enameledwire goes through a testing phase. These tests are based on mimicking real-world situations to assess the authentic abilities of the enameled
- Regular Follow-ups: Follow-up audits are conducted after the UL certifications are given.It helps determine continuous safety, performance, and compliance with relevant standards.
Conclusion
We hope you now understand the importance and significance of getting a UL certification for enameled wire. Are you looking for reliable UL-certified enameled wire? If yes, then Jingda is a great option for you. We are well-known and trusted manufacturers of enameled wires. You can also get custom wire solutions from us at affordable prices. For us, quality is a top priority, and we treat all customers equally. For any query, call us any time. We are happy to answer your questions regarding our products.
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