Shear Bolt Cable Lugs are essential for modern power cable terminations, delivering reliable, gas-tight connections without the need for crimping tools. These mechanical connectors use calibrated shear-off bolts to ensure consistent contact pressure, making them ideal for MV and LV applications in substations, transmission lines, and utility networks. For engineers and specifiers, mastering the function and benefits of these torque-controlled lugs is key to ensuring long-term electrical integrity and installation efficiency.
1. Introduction
Electrical systems, especially in the industrial and utility sectors, rely on high-quality connectors to ensure consistent performance and safety. Shear bolt lugs offer a solution for safely connecting cables in low, medium, and high-voltage applications. In this article, we will dive deep into what shear bolt cable lugs are, their key features, how they work, and where they are used, with a special focus on helping electrical professionals compare brands and products.
2. The Importance of Shear Bolt Cable Lugs in Electrical Connections
The shear bolt connector is crucial for ensuring a strong electrical and mechanical connection in a wide range of power systems. Here’s why they’re so important:
Precise Torque Control: Shear bolt lugs are designed with bolts that shear off at a predetermined torque. This ensures that the correct clamping pressure is applied, preventing over-tightening or under-tightening, which can lead to connection failures.
Reliability: A solid, secure connection is key in electrical systems. Shear bolt lugs are known for their reliable performance, especially in harsh environments where other connection types might fail.
Safety: These lugs ensure that the cables are firmly connected, reducing the risks of loose connections that can cause overheating, fires, or electrical failures.
3. What Are Shear Bolt Cable Lugs?
Shear Bolt Cable Lugs are torque-controlled mechanical connectors engineered to deliver consistent, high-performance cable terminations without the use of hydraulic crimping tools. These lugs feature a pre-engineered shear bolt mechanism that ensures precise clamping pressure—once the specified torque is reached, the bolt head cleanly breaks off, guaranteeing a secure and low-resistance electrical connection.
This makes Shear Bolt Cable Lugs ideal for critical applications across low and medium voltage systems, including underground distribution, substation equipment, and renewable energy installations. The design eliminates the risks associated with under- or over-tightening, offering mechanical shear lug technology that standardizes connection quality regardless of installer experience.
Construction Materials & Electrical Parameters
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Body Material: High-conductivity aluminum alloy (EN AW 6061-T6), tin-plated (≥12 μm) for improved corrosion resistance and to support bimetallic transitions (e.g., aluminum copper cable lugs).
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Compatible Conductors: Solid or stranded copper, aluminum, ACSR, AAAC, and sector-shaped conductors.
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Cable Size Range: 25 mm² to 800 mm² depending on lug model and bolt configuration.
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Voltage Class: Suitable for LV (≤1kV) and MV (up to 36kV) systems; type-tested according to IEC 61238-1 Class A.
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Operating Temperature: -55°C to +155°C, with short-circuit tolerance above 250°C.
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Electrical Performance: Contact resistance ≤100 µΩ, tested for temperature rise and short-circuit withstand capacity.
SUNJ Shear Bolt Cable Lugs
Technical Features
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Shear-Off Bolts: Designed for calibrated torque (45–70 Nm), each bolt guarantees consistent compression and electrical continuity upon installation.
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Serrated Conductor Barrel: Enhances mechanical grip and minimizes micro-movement under load.
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Beveled Entry Design: Facilitates clean cable insertion and avoids conductor strand deformation.
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Anti-Oxidation Grease: Factory-filled to reduce interface resistance and ensure long-term joint stability.
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Optional Pre-Insulated Designs: Provide added safety in compact switchgear environments or outdoor terminations.
Application Advantages
Shear Bolt Cable Lugs outperform traditional crimp-type connectors in both convenience and reliability, particularly in the field:
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Tool-less and fast installation using standard hex keys
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Consistent performance across every termination, even in remote environments
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Suitable for cable lug applications in substations, MV switchgear, solar inverters, and more
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Compliant with IEC 61238-1, NFC 33-020, EN 50483, and CE/UL standards where applicable
Whether you’re specifying a torque-controlled cable lug for a 33kV solar feeder or selecting components for aluminum-to-copper transitions in underground networks, Shear Bolt Cable Lugs offer proven electrical and mechanical performance backed by global standards.
4. How Shear Bolt Cable Lugs Work
Understanding the operational principle of mechanical shear lugs is essential for their effective use. Here’s how they work:
- Cable Insertion: The stripped end of the cable is inserted into the conductor sleeve of the lug.
- Tightening the Shear Bolt: The shear bolt is tightened until it reaches the designated torque value. At this point, the bolt head shears off, signaling the proper torque has been applied.
- Optimal Connection: Once the bolt head is sheared, the connection is made with the right amount of pressure, ensuring a safe and stable electrical and mechanical bond.
This process ensures that the lug is installed with precision and reliability, providing optimal performance in various electrical systems.
5. Shear Bolt Cable Lugs: Application Scenarios and Industry Standards
Shear bolt cable connectors are used extensively in low-voltage (LV) and medium-voltage (MV) systems. The ability to control shear bolt lug torque during installation ensures that the connections are secure and resistant to mechanical stresses. This makes them ideal for critical applications like power distribution, telecommunications, and renewable energy systems.
Applications:
Low Voltage (LV) and Medium Voltage (MV) Cable Connections:
Used extensively in power distribution and telecommunication systems, shear bolt cable lugs ensure stable connections in environments that require consistent performance.
High Voltage (HV) Systems:
In high-voltage transmission lines, shear bolt lugs are essential for maintaining robust connections that can withstand the mechanical and electrical stresses encountered in these applications.
Indoor and Outdoor Installations:
Shear bolt lugs are designed to work efficiently in both indoor and outdoor installations, protecting against environmental factors like humidity, dust, and extreme temperatures.
Renewable Energy Systems:
Used in wind and solar power systems, shear bolt lugs ensure secure connections for medium-voltage power lines, critical for transferring electricity from renewable sources to the grid.
Industry Standards:
IEC 61238: Ensures the lug’s compatibility with industry standards for electrical installations.
UL and CE certifications: Verify product quality and safety, especially for use in regions with stringent regulatory standards.
By complying with these standards, shear bolt lugs ensure that installations meet global safety and performance requirements.
6. Conclusion: Why Choose Shear Bolt Cable Lugs?
Shear Bolt Cable Lugs
For electrical professionals and purchasers, choosing the right shear bolt connector is crucial for ensuring the safety, reliability, and efficiency of electrical systems. These lugs offer:
- Easy installation with minimal tools required.
- Precise torque control that guarantees reliable and secure connections.
- Versatility in application across various voltages and conductor types.
- Durability and resilience in harsh environments.
When comparing different brands, consider factors like material quality, certifications, and additional features such as pre-insulated designs or advanced corrosion resistance. Whether you’re working on industrial installations, utility networks, or renewable energy projects, shear bolt cable lugs provide a critical solution for high-performance electrical connections.
Call to Action: When evaluating shear bolt lugs for your next electrical project, make sure to consider the technical specifications, application scenarios, and brand reliability. Choosing the right product can greatly enhance the safety and longevity of your electrical systems.