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When selecting armored optical fiber cables for underground networks, it's essential to consider installation environments, mechanical protection needs, fiber specifications, and environmental factors. In this guide, we’ll discuss two common installation methods for underground fiber optic cables: Duct Installation and Direct Buried Installation, and provide insights on how to choose the right fiber optic cable for each scenario.
Fiber Optic Cables are crucial components for reliable, high-speed communication networks, and their protection is a key consideration for underground installations. These cables are often subjected to harsh conditions, so selecting the right type is vital for ensuring long-term performance and protection against external environmental factors.
Duct installation involves placing fiber optic cables inside protective underground ducts. This installation method is commonly used in urban and suburban environments where the protection of the cables from external damage is necessary. Ducts provide a physical barrier, protecting the cables from moisture, physical damage, and environmental stress.
Protection from External Damage: The duct shields the cable from physical damage, water ingress, and environmental stressors.
Ease of Maintenance and Upgrades: Ducts allow for easy cable replacement or upgrades without the need for extensive excavation.
Scalability: Ducts can house multiple cables, making it easier to expand or upgrade networks in the future.
Moisture Resistance: Ensure that ducts used in high-moisture areas provide a strong moisture barrier to prevent water ingress, which can damage the cables.
Rodent Protection: In areas prone to rodent activity, it's important to choose cables with additional rodent-resistant armor to prevent damage.
Direct burial involves placing fiber optic cables directly into the ground without protective ducts. This method is cost-effective and commonly used in rural areas, long-distance trunk lines, or open-field conditions where ducts are impractical or not available. Direct burial is also commonly used for feeder cables in FTTH (Fiber to the Home) deployments.
Cost-Effective: Direct burial eliminates the need for ducts and reduces the overall installation cost.
High Durability: With proper protection, direct burial cables can withstand harsh underground conditions, such as soil pressure, water, and temperature fluctuations.
Protection Against Environmental Factors: Armored optical fiber cables with multiple layers of protection offer excellent resistance to external environmental factors like moisture, pressure, and mechanical stress.
Loose Tube Design: The optical fibers are housed in loose tubes filled with gel for water resistance, ensuring that they are protected from moisture.
Strength Member: A steel or FRP (Fiber Reinforced Plastic) central strength member provides tensile strength and structural integrity, which is essential for the mechanical protection of the cable.
Double Armoring: For extra durability, many direct-buried cables feature a combination of steel tape armor and a polyvinyl chloride (PVC) sheath. This construction enhances resistance to crushing, rodents, and other potential sources of damage.
Selecting the right armored fiber optic cable for underground networks involves assessing the installation environment, mechanical protection needs, and specific requirements of your fiber network. Below are key considerations when choosing between duct installation and direct buried installation.
Underground Environment | Recommended Cable Type | Key Features |
|---|---|---|
Standard soil conditions | GYTY53 (Dual PE sheath + steel tape armor) | Crush protection, general use in typical underground conditions |
High moisture or flooding areas | GYTA53 (AL-tape + steel tape dual armor) | Enhanced water resistance for wet environments |
EMI-sensitive or power-adjacent trenches | GYFTA53 (All-dielectric FRP strength member) | No metallic elements, ideal for power-sensitive areas |
Protection Requirement | Suggested Cable Type | Notes |
|---|---|---|
Strong crush & rodent resistance | GYTY53 / GYTA53 | Steel tape armor for protection against soil pressure and rodents |
Non-metallic design (no grounding) | Safer for power trenches and lightning-prone areas | |
Additional moisture blocking | AL-tape layer serves as an effective moisture barrier |
Network Application | Recommended Fiber Type | Explanation |
|---|---|---|
Long-haul trunk transmission | G.652.D | Standard single-mode fiber with low attenuation for long-distance transmission |
Shorter access / FTTH backbone | G.657.A1 | Bend-insensitive, compatible with G.652.D, ideal for FTTH applications |
Dense duct routes or sharp turns | G.657.A2 | Ultra bend-resistant for tight underground ducts and sharp turns |
When choosing armored optical fiber cables for underground networks, it’s crucial to consider the specific installation environment, mechanical protection needs, and the type of fiber required. Both duct installation and direct buried installation offer unique advantages based on the network’s demands, from cost-efficiency to long-term durability and flexibility.
At CROFC, we specialize in providing high-quality fiber optic cables designed for both duct and direct buried installations. Our products are engineered to withstand harsh conditions, ensuring reliable, long-lasting performance for your underground fiber optic network.
Q1: What’s the difference between duct installation and direct buried installation for fiber optic cables?
A: Duct installation uses protective ducts for easier maintenance, while direct burial places cables directly in the ground for a cost-effective solution.
Q2: Can I use the same fiber optic cable for both installations?
A: Yes, but only if the fiber cable is rated for both duct AND direct burial-standard duct-only cable will fail if directly buried.
Q3: How do I choose the right fiber optic cable for my underground network?
A: Consider environmental factors like soil conditions, moisture, and rodent activity. For harsh environments, choose cables with extra protection.
