Trust but verify. This concept applies not only to everyday life but also to electrical components like cable lugs. With countless cable lug manufacturers worldwide, many overlook the importance of regular product testing. This brings up a simple but crucial question:
Do you trust your cable lugs?
At Axis, we have been manufacturing a wide range of electrical lugs and connectors for the past 30 years. Our products include copper, aluminum, and bimetallic lugs used in various applications like solar plants, substations, transformers, control panels, switchgear, and more.
In this blog, you will understand how to guarantee the quality of your cable lugs by understanding the necessary electrical and mechanical tests. By the end of this post, you’ll be familiar with the following tests:
- Conductivity Test
- Heat Cycling Test
- Tensile Test
- Secureness Test
- Pull-Out Test
But first, let’s briefly discuss lugs and their importance to electrical safety.
What Are Electrical Lugs?
An electrical lug is a component used to connect a wire or cable to another electrical component or termination point. They are designed to create a secure, mechanically strong, and electrically conductive connection between the conductor and the component it’s connected to.
In cases where directly connecting the conductor to the equipment isn’t practical (due to limited space, varying conductor sizes, etc.), lugs come into play. Electrical lugs can be primarily made of copper, aluminum, or bimetallic (a combination of copper and aluminum).
Types of Lugs
The market offers various types of lugs, each with specific applications. Some popular types include:
- Copper Lugs: Ideal for high-conductivity connections.
- Aluminum Lugs: Lightweight and cost-effective, best for aluminum conductors.
- Bimetallic Lugs: For connecting copper cables to aluminum terminals.
Talk to our engineers!
Testing Electrical Lugs: 5 Types of Tests
1. Conductivity Test
Objective: To measure the electrical conductivity of a lug to ensure its quality.
This test is conducted using a conductivity testing machine, which measures the metal’s conductivity in percentages based on the International Annealed Copper Standard (IACS). Pure copper is considered 100% conductive.
For copper lugs, the electrical conductivity must exceed 97% to qualify as Electrolytic Tough Pitch (ETP)-grade copper. At Axis, our copper lugs have a conductivity of 99% IACS, ensuring high-quality copper material.
2. Heat Cycling Test
Objective: To assess a lug’s long-term performance under varying thermal conditions.
The goal of this test is to assess the lug’s long-term performance. How do we conduct this test? We connect multiple lugs with suitable cables in a series to form a test loop. We then evaluate the functional properties of six lugs and one reference conductor. This reference conductor is part of the loop, and we control its temperature to reach about 120 to 140 degrees Celsius by injecting current.
After all the lugs and the reference conductor are heated and stabilized, they are cooled back to ambient temperature. We repeat this heating and cooling cycle 1,000 times, which takes approximately 2 months to complete. The lug passes the test if it meets the standard criteria as per IEC 61238 for resistance and temperature, proving that our lugs are built for longevity.
Note: There are two different types of tests for lugs. The one described here follows the guidelines of the IEC 61238, while another is the Current Cycling Test according to UL 486-A 486-B. However, both tests are conducted using the same equipment in our lab.
3. Tensile Test
Objective: To determine if the lug can withstand the required tensile load.
The aim of this test is to determine if the lug can withstand the required tensile load without being damaged. How do we perform this test? This test is performed on the Tensile Testing machine. We set the required tensile load value and duration to apply the tensile load for 1 minute as per Table 4 of IEC 61238.
If the slippage does not exceed 3 mm, the sample is compliant to the standard. As you can see here, the lug remained undamaged, and there was no slippage of the conductor. This confirms that it can handle the required tensile load in real-world applications.
4. Secureness Test
Objective: To ensure that the cable lug remains firmly attached to the cable under mechanical stress.
This test ensures that the cable lug will remain firmly attached to the cable under mechanical stress, preventing any accidental disconnection.
How do we conduct this test? The lugs are first crimped onto the cables using the defined crimping tool and the specified number of crimps. We have a separate video on how to crimp cable lugs, the link is right here and also in the description.
Finally, the crimped lug along with the cables are installed on the secureness test equipment. Weights, as specified in the UL486A/486B standard are connected to the cables. These cables undergo rotation for the duration specified in the standard. After completing the designated time, no slippage of the cables from the lugs should occur. In the case of Axis-manufactured lugs, no slippage was observed. This confirms that Axis lugs will remain securely attached to the cables even under mechanical stress.
5. Pull-Out Test
Objective: To verify the mechanical strength of the bond between the lug and the cable.
This test determines the mechanical strength of the bond between the cable lug and the cable.
How do we conduct this test? This test is performed as specified in the UL486A 486B standard. The lug is first fixed to a standard cable, then it is subjected to a direct tensile load that gradually increases.
The force applied during this test is measured in Kilo Newtons. The standard requirement is that the lug must withstand a minimum pull-out force, specific to its size and design. For example, this Axis Copper Lug is expected to withstand a pull-out force of over 1000 Newtons, which is 1 Kilo Newton.
This test verifies that even under extreme pulling scenarios, the lug’s attachment to the cable will remain secure and intact. This is important because the electrical connection should not be compromised under mechanical stress.
Conclusion
Understanding and performing these tests are essential to ensuring the quality and safety of your electrical lugs. All Axis-manufactured lugs undergo these tests as per IEC 61238 and UL 486A/486B standards at our Axiom Lab in Mumbai. The lab is accredited by the National Accreditation Board for Testing and Calibration Laboratories (NABL) and approved by Underwriters Laboratory (UL).
With over 30 years of experience, Axis manufactures and supplies a wide range of electrical lugs to more than 100 countries. Our team of over 50 engineers is here to help you design and install your lugs, connectors, and lightning protection systems.
Our products are trusted in solar farms, data centers, and even everyday residential buildings. If you’d like more information on insulators, lightning protection, grounding systems, or other electrical engineering topics, subscribe to our weekly newsletter or check out our other blog posts.
Stay safe and ensure your lugs are properly tested and up to standard!
Thank you for reading the blog, Axis is a leading manufacturer and supplier of Electrical Components to over 80+ Countries. Talk to our industry expert by visiting our Contact Us section. You can also watch our videos by our experts – click here.
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