Cable Ducts

Last updated on 2023-06-27 4 mins. to read

Underground cable ducts are indispensable infrastructure components for the secure and efficient transmission of electricity, telecommunications and data services. The installation of these ducts requires planning, execution, and compliance with local regulations.

By considering the following factors when installing underground cable ducts, we can ensure that your infrastructure project is successful, durable, and efficient.

Planning, permits and regulations

A well-designed duct system is necessary for efficient cable installation and maintenance in the future. Consider factors such as depth, distance between ducts, and cable type when installing cables. In addition, plan for potential future system expansions and enhancements.

Before beginning any endeavour, it is essential to research and adhere to local regulations and obtain any necessary permits. These may include environmental factors, utility certifications, and right-of-way authorizations. Compliance with local regulations will facilitate a seamless installation process and prevent potential legal issues.

Before digging, identify and locate all existing subsurface utilities to prevent accidental damage to gas, water, and other utility lines. This will help assure worker safety and prevent expensive repairs or fines.

Duct bank installation

Installation, Soil Conditions and Materials

Soil conditions can have a substantial effect on the installation process and the durability of a duct system. Evaluate the soil to determine the optimal installation method, depth, and duct material in order to ensure the duct's stability and durability.

Select the proper duct material and installation method based on soil conditions, load requirements, and local regulations. Popular materials include PVC, HDPE, and fibreglass, and installation techniques include open trench, directional drilling, and microtrenching. Bed and backfill the ducts with suitable materials to protect them from damage caused by ground movement or large loads. This will aid in maintaining the duct system's integrity over time.

The distance between the ducts and the encircling materials largely determines the cables' current carrying capacity (Cable Sizing) and temperature. Maintain adequate separation between ducts in accordance with industry standards and local regulations to avoid this. In addition, choose bedding and backfill materials with high thermal conductivity, allowing for effective heat dissipation and preventing cables from overheating.

Install warning tapes or marker posts to alert future excavators of buried ducts and cables. This precaution helps prevent inadvertent damage during future construction or maintenance projects.

Design the duct system with adequate ventilation and discharge to prevent the accumulation of gases or water within the ducts, which can damage cables. This factor will aid in protecting the cables and extending their lifespan.

Draw Pits and Cable Pulling

Draw pits, also referred to as draw boxes or splice boxes, are indispensable components of an underground cable duct system. They facilitate cable installation, maintenance, and repairs along the duct route by providing access points at strategic locations. Consider the following when incorporating draw basins into your duct system:

  1. Location: Place draw pits at regular intervals and at direction, elevation, or duct size changes. This makes cable pulling simpler, reduces cable tension, and reduces the risk of cable injury during installation.
  2. Size: Ensure that the draw pit is large enough to accommodate the number of cables, splices, and any other apparatus necessary for cable installation or maintenance.
  3. Design: Design draw pits with appropriate drainage, ventilation and secure access covers to protect cables and equipment from water and gas accumulation.
  4. Material: Use concrete or polymer concrete to construct draw pits that can withstand large loads and resist corrosion.
  5. Safety: Follow safety guidelines when working within draw pits, including proper ventilation, confined space entry procedures, and the use of fall protection equipment when necessary.

Use the proper cable-hauling equipment, techniques, and lubricants to prevent cables from being damaged during installation. This will aid in ensuring the performance and dependability of the installed cables.

Quality Assurance and Safety

Regularly inspect the installation process to ensure that best practices are followed, and the duct system meets the specifications. This will aid in ensuring a successful installation and reduce the likelihood of future issues.

Keep detailed as-built drawings and documentation of the underground duct system, including information on its location, depth, and cables. For future maintenance and expansion initiatives, this information will be invaluable.

Ensure that all personnel involved in the installation process are aware of potential dangers and adhere to appropriate safety procedures to reduce the likelihood of accidents or injuries. A safe workplace is crucial to the success of an endeavour.