In the realm of optical fiber deployment, the choice between overhead and buried installation methods shapes network reliability, cost, and longevity. As a leading provider with two decades of expertise in fiber optic solutions, QZ Group understands the critical factors influencing this decision. This in-depth guide dissects the technical nuances, installation workflows, and real-world applications of both methods, empowering engineers and planners to make data-driven choices for their projects.
1. Core Differences: Overhead vs. Buried Installation
1.1 Technical Specifications
1.2 Design Philosophy
Overhead: Suited for rapid deployment in rural or suburban areas with existing pole networks.
Buried: Ideal for urban centers, industrial zones, or environments requiring permanent, low-maintenance infrastructure.
2. Overhead Fiber Optic Installation: Techniques and Best Practices
2.1 Cable Types and Materials
①ADSS (All-Dielectric Self-Supporting):
Dielectric construction prevents grounding issues near high-voltage power lines.
QZ Group’s ADSS-288B1.3 supports 288 fibers with tensile strength up to 12,000N.
②Messenger-Supported Cables:
Steel messenger wire supports cable weight, suitable for spans up to 200m.
QZ Group’s GYTA53 messenger cables feature double armor for rodent resistance.
2.2 Step-by-Step Installation Workflow
1. Pole Route Planning
①Span Calculation:
Maximum span: 50–100m (depends on cable weight and climate).
QZ Group’s pole spacing calculator considers ice loading (up to 50mm) and wind speed (up to 320km/h).
2. Messenger Wire Installation
Tensioning: 15–20% of the wire’s breaking strength to allow for thermal expansion.
Anchoring: Concrete dead-end poles with guy wires for stability.
3. Cable Lashing
①Lashing Methods:
Self-lashing (for ADSS): ADSS tool ensures 0.5mm/m tension uniformity.
Messenger lashing: Polyester lashing wire with UV protection.
4. Termination and Splicing
Aerial splice enclosures: IP65-rated, sun-resistant.
2.3 Challenges and Mitigation
①Wind Vibration (Aeolian Vibration):
Solution: QZ Group’s Stockbridge dampers reduce vibration-induced microbends.
②Lightning Strike Protection:
Grounding: Copper grounding wires every 500m for ADSS cable.
3. Buried Fiber Optic Installation: Underground Mastery
3.1 Cable Design for Burial
①Armored Cable:
GYXTW: Steel wire armor, water-blocking tape (GYXTW-288 supports 288 fibers).
GYFTY: FRP (Fiberglass Reinforced Plastic) for non-conductive environments.
②Duct System:
HDPE conduits (110mm diameter, 160° heat resistance).
3.2 Installation Methods
1. Trenching (Traditional)
①Trench Specifications:
Residential: 60–75cm depth (with warning tape).
Road crossings: 120cm depth with concrete encasement.
②QZ Group’s Trenching Tips:
Use vacuum excavation to avoid utility damage.
Lay sand bed + brick protection for cable durability.
2. Horizontal Directional Drilling (HDD)
Applications: Under highways, rivers, or railways.
QZ Group’s HDD Process:
Pilot hole drilling with Gyro-Trak guidance (0.5% depth accuracy).
Reaming to 1.5x cable diameter.
Cable pulling with tension control (<0.5% of breaking strength).
3. Micro-trenching (Urban Areas)
Technique: 5–10cm wide trenches for shallow burial (30cm depth).
QZ Group’s Micro-trench Cables: GYFTZY with thin armor for easy pulling.
3.3 Post-Installation Protection
①Rodent Deterrence:
Stainless steel armor + bitter-tasting jacket (GYTS).
②Waterproofing:
Gel-filled cables (water-blocking grade: IEC 60794-1-2).
4. Application Scenarios
4.1 When to Choose Overhead
Rural Broadband:
Example: A Southeast Asian village project used QZ Group’s ADSS-144 to connect 200 homes in 3 weeks.
Temporary Networks:
Construction sites, disaster relief operations.
4.2 When to Choose Buried
Urban FTTH:
Case Study: A European city deployed 500 km of QZ Group’s GYXTW-288 in ducts, supporting 10G PON to 100,000 homes.
Industrial Parks:
Chemical plants, where buried cables avoid corrosion from airborne chemicals.
5. QZ Group’s Technical Solutions
5.1 Overhead Product Portfolio
ADSS Cables:
WU-ADSS-288B1.3: 288 fibers, 12,000N tensile strength, suitable for 110kV power line crossings.
Messenger Systems:
WU-MSG-70: 70mm steel messenger wire, galvanized for 50-year durability.
5.2 Buried Product Portfolio
Direct Burial Cables:
WU-GYXTW-288: Steel armor, water-blocking gel, supports 288 fibers for metro backhaul.
Duct Systems:
WU-HDPE-110: 110mm conduits with built-in tracer wires for easy location.
6. Installation Best Practices
6.1 Overhead Installation Tips
Pole Loading Calculation:
Use QZ Group’s pole loading software to account for cable weight, ice, and wind.
Splice Enclosure Placement:
Every 2–3 km for easy maintenance, mounted on poles at 5m height.
6.2 Buried Installation Tips
Soil Analysis:
Clay soil: Use GYTS cables with aluminum composite tape.
Sandy soil: Deploy sand-resistant armor (GYTA53).
Marker Placement:
Concrete markers every 50m, with GPS coordinates logged in QZ Group’s Fiber GIS platform.
7. Future Trends in Fiber Installation
Robotic Trenching:
Autonomous trenchers with AI-driven utility detection (QZ Group’s R&D in progress).
Aerial Drones for Cable Lashing:
Drones equipped with robotic arms for high-altitude cable installation.
Smart Cables:
IoT-enabled cables with built-in temperature and strain sensors.
8. Choosing the Right Method: A Decision Matrix
8.1 Key Considerations
Project Timeline:
Overhead: Faster deployment (suitable for urgent projects).
Buried: Longer installation but minimal future disruption.
Environmental Factors:
Seismic zones: Buried cables with flexible armor.
High-wind areas: Overhead cables with reinforced messengers.
Budget vs. Longevity:
Tight budget: Overhead (lower CAPEX).
Long-term reliability: Buried (lower OPEX).
