What We Do
SNTF Utilities installs utilities (primarily fiber) underground via horizontal directional drilling , trenching, and plows, and overhead utilizing bucket trucks. We install conduit, blow the fiber through the conduit, splice the fiber, set all structures, and run the drops to homes, with a focus on safety.
Our Processes
Horizontal Directional Drilling (HDD) for Fiber Installation
Horizontal Directional Drilling (HDD) is a trenchless construction technique used to install underground utilities, such as fiber optic cables, without digging extensive open trenches. It involves creating a guided borehole beneath obstacles like roads, rivers, buildings, or landscapes, minimizing surface disruption, environmental impact, and restoration costs. This method is particularly popular for fiber optic installations in urban or residential areas where high-speed internet expansion requires crossing existing infrastructure efficiently. HDD uses specialized drilling rigs that can steer the drill path, allowing for precise placement of conduits or cables over distances ranging from short urban shots (e.g., 300 feet) to longer bores in challenging terrains.
Project Planning and Site Preparation
- Begin with surveying the site, including geotechnical assessments to understand soil conditions (e.g., sand, clay, rock) and potential obstacles. Use utility locators (e.g., ground-penetrating radar or electromagnetic tools) to mark existing lines and avoid damage. Design the bore path, including entry/exit points, depth (typically 3-10 feet for urban fiber), curvature, and length. Obtain permits and plan for drilling fluid management to prevent environmental spills. Select the right HDD rig based on bore length and ground type—smaller rigs for short urban jobs, larger or dual-rod models for rocky areas.
- Drilling the Pilot Hole Position the HDD rig at the entry point. A steerable drill bit (with an asymmetrical tip for directional control) creates a small-diameter (e.g., 4-6 inches) pilot borehole along the planned arc-shaped path. Drilling fluid is pumped through the drill string to cool the bit, remove cuttings, and stabilize the hole. A locator (walker) tracks the drill head's position in real-time using a sonde (transmitter) for adjustments. The pilot hole emerges at the exit point, typically taking hours to days depending on length.
- Pre-Reaming (Enlarging the Borehole) Once the pilot hole is complete, replace the drill bit with a reamer (a larger cutting tool) and pull it back through the hole to enlarge it to the required diameter (e.g., 1.5-2 times the conduit size for fiber). This may involve multiple passes with progressively larger reamers, especially in hard soils. Drilling fluid continues to flow, carrying away debris and maintaining hole integrity.
- Pullback and Conduit Installation Attach the conduit (usually HDPE pipe for fiber protection) to a reamer or pull head with a swivel (to prevent twisting). The rig pulls the assembly back from the exit to the entry point, installing the conduit in one continuous segment. For fiber, an aircraft cable or pulling tape is often pre-inserted into the conduit to aid later cable installation. Monitor tension to avoid damaging the conduit.
- Fiber Optic Cable Installation With the conduit in place, install the fiber optic cable. For shorter distances, pull it through using the pre-installed tape or rope. For longer runs, use air-assisted blowing (jetting) where compressed air propels the cable through the conduit. This protects the fragile glass fibers from excessive tension.
- Splicing and Termination At connection points (e.g., handholes, vaults, or endpoints), splice the fiber strands. This involves stripping the cable jacket, cleaning the fibers, and fusing them using a fusion splicer (which aligns and melts the ends together for low-loss connections). Protect splices in enclosures. Terminate ends at equipment like optical distribution frames or ONTs (for home connections). Splicing ensures signal continuity across segments.
- Testing, Cleanup, and Restoration Test the installed fiber using OTDR (Optical Time-Domain Reflectometer) for loss, breaks, or bends. Clean up drilling fluids (recycle or dispose per regulations), restore entry/exit pits, and backfill any minor surface disturbances. Final as-built documentation records the installation for future reference
Aerial Fiber Installation
Aerial fiber optic cable installation involves suspending fiber cables above ground on utility poles or structures, rather than burying them underground. This method is faster and often more cost-effective than trenching, especially in rural areas, along roadsides, or where underground access is limited or obstructed (e.g., rocky soil, dense urban utilities). It's commonly used for expanding broadband networks, connecting neighborhoods, or spanning long distances.
Aerial installations come in a few main types:
- Lashed (or strand-and-lash): Fiber cable is attached (lashed) to a pre-installed steel messenger strand (suspension wire) using lashing wire. This is very common and flexible for adding more cables later.
- ADSS (All-Dielectric Self-Supporting): Fully non-metallic cable designed to support its own weight without a steel messenger. It avoids grounding issues and can be placed in power spaces on poles.
- Figure-8: Self-supporting cable with an integrated steel messenger in a figure-8 cross-section for simpler, one-step hanging.
The process shares similarities with HDD fiber installation (e.g., splicing and testing), but focuses on pole work, tensioning, sagging, and climbing safety.
Why Choose Aerial Installation?
- Faster deployment with less disruption (no digging).
- Lower initial cost in many scenarios.
- Easier mid-span access for future splices or drops.
- Challenges include weather exposure, pole loading limits, clearance rules from power lines, and risks from wind/ice loading.
The Full Process of Aerial Fiber Installation
The process requires trained crews (often with bucket trucks or climbing gear), safety certifications (e.g., pole/tower climbing, electrical awareness), permits, and coordination with pole owners (utilities, cities). Always follow NESC (National Electrical Safety Code) clearances and local regs.
- Project Planning and Site Preparation Conduct a detailed survey of the pole line: measure spans (typically 200–500 ft), check pole condition/strength, note angles (>20–30° needs special hardware), existing attachments, and clearance to power lines (telecom space is usually below power). Perform pre-installation OTDR testing on the cable reel. Obtain permits, "make-ready" approvals (adjusting existing attachments), and plan for slack loops at poles for splicing. Choose cable type based on span lengths, environment (e.g., ADSS for electric-heavy poles), and fiber count.
- Pole Preparation and Hardware Installation Install or verify the messenger strand if using lashed method (tensioned steel wire between poles using dead-end clamps and suspension clamps). For ADSS or Figure-8: Install pole-mounted hardware like tangent supports, dead-end grips, or suspension clamps at each pole. Attach bonding/grounding if metallic components are used (not needed for ADSS). Ensure proper spacing in the communications zone (below power conductors).
- Cable Placement (Deployment)Two main methods: moving reel (preferred when accessible) or stationary reel
- Moving Reel Method (common for lashed and ADSS): Mount the cable reel on a trailer or truck that drives along the pole line. Pay out cable from the top of the reel, lift it to strand level (using bucket truck or hand lines), and feed it into temporary supports ("J" hooks or blocks) at each pole. For lashed: Simultaneously or right after, use a lasher tool to wrap stainless steel lashing wire around the cable and messenger (every span). Start with slack for splicing. For ADSS/Figure-8: Tension and secure directly into permanent clamps as you go. Maintain proper sag (calculated for weight, wind, ice) and minimum bend radius.
- Stationary Reel Method (used when access is limited): Position reel at one end. Install temporary cable blocks/sheaves under the strand at each pole. Pull the cable through using a winch and pulling grip/swivel at the far end (monitor tension to avoid damage). Once pulled in, lash it back toward the reel (for lashed) or transfer to permanent hardware.
- Leave extra slack (e.g., 16–20 ft) at poles for splicing/termination.
- Cable Securing and Sag Adjustment Install permanent suspension clamps, dead-ends, and vibration dampers if needed. Tension the cable/strand to engineered sag levels (using dynamometers). Secure lashing wire ends with clamps. Double-lash in high-wind areas for security. Fiber Optic Cable Splicing and Termination At poles with closures (e.g., every few spans or at splits): Create slack loops (coiled on snowshoes or brackets) for access. Enter splice closures mounted on poles. Strip cable jackets, clean fibers, cleave precisely, and fusion splice strands using a fusion splicer (align and arc-weld for low-loss joints). Protect splices in splice trays/enclosures. For terminations (e.g., to equipment or drops): Use connectors (e.g., SC/APC) or pre-terminated pigtails. Ground metallic parts if applicable.
- Fiber Optic Cable Splicing and Termination At poles with closures (e.g., every few spans or at splits): Create slack loops (coiled on snowshoes or brackets) for access. Enter splice closures mounted on poles. Strip cable jackets, clean fibers, cleave precisely, and fusion splice strands using a fusion splicer (align and arc-weld for low-loss joints). Protect splices in splice trays/enclosures. For terminations (e.g., to equipment or drops): Use connectors (e.g., SC/APC) or pre-terminated pigtails. Ground metallic parts if applicable.
- Testing, Cleanup, and As-Builts Perform OTDR testing for loss, reflections, bends, or breaks. Visual inspection (from ground or bucket) for proper sag, clearance, and hardware. Clean up debris, remove temporary blocks. Document as-builts: pole numbers, slack locations, splice points, fiber assignments.
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SNTF Utilities
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