AFL’s All-Dielectric Self-Supporting (ADSS) fiber optic cables represent a significant advancement in the deployment of fiber networks, particularly in environments where overhead electrical infrastructure already exists. These cables are designed for installation in both distribution and transmission systems without the need for additional support or messenger wires, streamlining the deployment process and reducing costs. This guide draws from official installation instructions and technical specifications provided by AFL, offering a detailed overview of the methods, precautions, and considerations involved in ADSS cable installation.
ADSS cables are ideal for short-span applications, typically under 500 feet, and are often used in scenarios where live-line installation is required. The self-supporting nature of ADSS cables allows for single-pass installation, making them a cost-effective and efficient option for expanding fiber networks. AFL provides a comprehensive set of guidelines and hardware solutions to ensure compatibility and ease of integration during the design and installation phases.
General Installation Information
The installation of ADSS cables follows methods similar to those used for overhead power conductors and metallic messenger wires. The primary objective is to ensure the cable is properly supported and tensioned to avoid mechanical stress and maintain the integrity of the optical fibers. According to the installation instructions, the methods provided are intended as general guidelines and must be adapted to local conditions and customer requirements.
AFL emphasizes that each installation will be influenced by factors such as local climate, terrain, and the existing infrastructure. Therefore, it is crucial to consult the specific application documents provided by AFL, which include minimum separation and clearance requirements, sag tables, and cable data. These documents are typically provided to customers based on the specific use case of the ADSS cable.
Local, national, and industry-specific safety codes must also be adhered to during installation. In the event of a conflict between these codes and the installation guidelines, the applicable codes take precedence. This ensures that the installation not only meets technical requirements but also complies with the necessary safety standards.
Safety Precautions and Environmental Considerations
Safety is a paramount concern when installing ADSS cables, especially in environments where overhead electrical conductors are present. One critical issue is the potential for leakage current to be induced onto the ADSS cable, even when it is located a considerable distance from the phase conductors. This leakage can occur due to the cable's proximity to conductors and the surface resistivity of the cable jacket, which is influenced by environmental factors such as moisture and contaminants.
During wet conditions, the surface resistivity of a clean, dry cable can drop from 10^14 Ω/ft to as low as 10^6 Ω/ft. This significant reduction in resistance increases the risk of electrical discharge. Therefore, AFL explicitly advises against installing ADSS cables on active towers during wet environmental conditions. Such installations can lead to dangerous scintillation or flashovers, which can damage the cable and pose a risk to personnel and equipment.
To mitigate this risk, AFL provides a formula to calculate the safe approach distance (SD) between phase conductors and ADSS cables. The formula is:
SD = E / 15
Where: - SD is the distance in inches - E is the phase-to-ground voltage in kilovolts (kV)
This calculation is based on the flashover voltage of a grounded rod in air, which is approximately 15 kV per inch for large gaps. By applying this formula, installers can determine the minimum safe distance required to prevent electrical discharge, ensuring the safety of both the installation and the surrounding infrastructure.
Installation Equipment and Cable Reels
ADSS fiber optic cables are typically supplied on non-returnable wooden reels, which are covered with a protective layer to prevent damage during transportation. These reels are lagged with flexible material to provide additional protection. However, if the cable is not to be installed within four months of delivery, it is recommended that it be shipped on steel reels to ensure long-term protection and prevent degradation of the cable's properties.
Steel reels offer enhanced durability and resistance to environmental factors, making them a suitable option for extended storage periods. Installers are advised to contact AFL for more information or to request shipment on steel reels if the installation timeline is delayed beyond the recommended four-month window.
Installation Methods and Techniques
The installation of ADSS cables involves several key steps, including route identification, cable support, sagging and tensioning, and the use of appropriate hardware. The installation process is designed to be similar to that of overhead power conductors, leveraging existing infrastructure and installation techniques to streamline the deployment.
Route identification is a critical first step, as it involves mapping out the path the cable will take from one support structure to another. This step ensures that the cable is installed in a manner that minimizes exposure to environmental hazards and maximizes its operational lifespan. The route must also consider the existing electrical infrastructure, ensuring that the ADSS cable is installed at a safe distance from phase conductors and other electrical components.
Cable support is another essential aspect of the installation process. ADSS cables are self-supporting and do not require additional support wires, but they must be properly secured to pole attachment hardware. This hardware is designed to provide the necessary support while allowing for the natural movement of the cable due to temperature changes and wind loads. AFL provides a range of attachment hardware solutions to ensure compatibility and ease of installation.
Sagging and tensioning are crucial for maintaining the integrity of the ADSS cable. The cable must be tensioned appropriately to prevent excessive sag, which can lead to mechanical stress and potential damage. At the same time, the cable must not be over-tensioned, as this can cause strain on the fibers and reduce the cable's performance. AFL provides detailed sag tables and tensioning guidelines to help installers achieve the optimal balance between sag and tension.
Cable Support Hardware and Compatibility
AFL's commitment to providing a comprehensive solution for ADSS cable installation extends to the development of specialized support hardware. These hardware components are designed to work seamlessly with AFL's ADSS cables, ensuring compatibility and ease of integration during the installation process. The hardware includes a range of attachment solutions, such as dead-end fittings, tensioning devices, and suspension clamps, which are tailored to the specific requirements of ADSS cable installations.
The compatibility of these components with the ADSS cable is essential for maintaining the cable's performance and durability. By using AFL's proprietary hardware, installers can ensure that the cable is supported correctly and that all components work together efficiently. This not only simplifies the installation process but also reduces the risk of mechanical failures and maintenance issues over the cable's operational life.
Advantages of ADSS Cables
The advantages of ADSS cables are numerous, making them an attractive option for a wide range of applications. One of the most significant benefits is the ability to perform live-line installations, which is particularly useful in situations where electrical infrastructure is already in place. This capability eliminates the need for power outages during installation, reducing downtime and associated costs.
The self-supporting design of ADSS cables also contributes to their cost-effectiveness. By eliminating the need for additional support or messenger wires, the installation process is simplified, reducing labor and material costs. Furthermore, the ADSS cable's design allows for greater flexibility in pole placement, enabling more efficient use of right-of-way space and reducing the overall footprint of the installation.
Another key advantage is the limited maintenance requirements of ADSS cables. Once installed, these cables require minimal maintenance due to their durable construction and the absence of metallic components, which are prone to corrosion and degradation. This results in a longer operational lifespan and lower lifecycle costs, making ADSS cables a sustainable and cost-effective solution for fiber network expansion.
Technical Specifications and Variants
AFL offers two primary types of ADSS cables: gel-filled and gel-free. Each variant is designed to meet specific project requirements and environmental conditions. Gel-filled ADSS cables provide enhanced protection against moisture and contaminants, making them suitable for harsh environments where exposure to water and dust is a concern. These cables are often used in applications where long-term reliability and durability are essential.
On the other hand, gel-free ADSS cables are designed for environments where the presence of gel may pose a risk or where the cable needs to be lightweight and flexible. These cables are ideal for applications where ease of installation and reduced weight are priorities. The absence of gel also allows for faster deployment and reduces the risk of internal contamination, which can affect the performance of the optical fibers.
Both variants of ADSS cables are available in a range of specifications to accommodate different span lengths, load conditions, and environmental requirements. Installers are advised to consult the technical specifications provided by AFL to select the most appropriate cable for their specific project.
Conclusion
AFL's ADSS fiber optic cables offer a robust and efficient solution for deploying fiber networks in environments where overhead electrical infrastructure is present. The self-supporting nature of these cables, combined with their ability to be installed live, makes them a cost-effective and practical choice for both distribution and transmission applications. By following the detailed installation guidelines and using the appropriate hardware and techniques, installers can ensure the successful deployment of ADSS cables while maintaining the safety and integrity of the surrounding infrastructure.
The key considerations in ADSS cable installation include route identification, proper cable support, sagging and tensioning, and the use of compatible hardware. Additionally, environmental factors such as moisture and contaminants must be carefully managed to prevent damage to the cable and ensure long-term performance. By adhering to these guidelines and leveraging AFL's comprehensive support solutions, installers can achieve optimal results and maximize the benefits of ADSS technology.