Answer: Difficult terrain and adverse weather can significantly complicate OHTL stringing. For mountainous or remote areas, helicopter stringing is a valuable method for pulling pilot lines, minimizing ground disturbance and speeding up the process. Our specialized tensioners and pullers are designed with high-capacity and variable speed control, allowing for precise operation even in challenging conditions. Additionally, our equipment features robust hydraulic systems and sealed components to withstand harsh weather, ensuring reliable performance when you need it most. We also offer a range of all-terrain reel stands and conductor trailers to facilitate material transport in difficult environments.

A1: The most common methods for laying underground cables are:

• Direct Laying: The cable is buried directly in a trench. This method is economical but has the lowest protection against mechanical damage.

• Draw-in System: Cables are pulled through ducts or conduits. This provides excellent protection and allows for future replacement or expansion without re-excavation.

• Troughing System: The cables are placed in pre-cast concrete or fiberglass troughs, which are then covered. This method offers good protection and is ideal for situations where multiple cables need to be routed together.

The draw-in system is generally considered the most reliable due to its superior protection and ease of maintenance, despite a higher initial cost. For all these methods, we offer a comprehensive range of equipment, including trenchers, cable rollers, and pulling winches, to ensure a safe and efficient installation.

A cable termination is a crucial component that makes a secure and durable electrical and physical connection between a cable and a piece of equipment or another cable. Its primary purpose is to seal the cable end, preventing moisture ingress and protecting the insulation from environmental damage, which can lead to electrical failure.

There are three main types of cable terminations we offer:

• Heat-Shrink: This type uses heat-shrinkable components that, when heated, shrink down to form a tight, protective seal.

• Cold-Shrink: These terminations are pre-expanded and simply require the user to remove a supporting core, allowing the components to shrink and fit snugly around the cable without the need for an external heat source.

• Pre-Moulded Push-On: These terminations are designed to be pushed directly onto the cable end, providing a quick and reliable connection.

Safety is paramount in all electrical work, especially with underground cable projects. Key considerations include:

• Utility Mapping: Before any excavation, conduct a thorough survey to locate and mark all existing underground utilities (gas, water, telecom, etc.) to prevent accidental damage.

• Proper Trenching: Trenches must be dug to the appropriate depth and width according to local regulations and the cable's voltage.

• Cable Protection: Use appropriate bedding (a layer of sand) and mechanical protection (tiles or marker tape) to shield the cable from sharp objects and warn future excavators of its presence.

• Proper Equipment: Use specialized equipment such as cable rollers, winches with tension control, and drum jacks to handle and install cables correctly, preventing damage from excessive pulling tension or tight bending radii.

We provide a full range of high-quality, durable equipment designed to meet international safety standards, helping to ensure your projects are completed safely and efficiently.

Tension stringing is the modern, preferred method for installing overhead conductors. It involves using a puller-tensioner system to keep the conductor off the ground throughout the entire process, maintaining a constant tension. This technique is critical for preventing damage to the conductor, especially over obstacles like roads, railways, and existing power lines. In contrast, slack stringing involves allowing the conductor to drag on the ground, which can cause significant damage and is generally not recommended for modern, high-quality conductors. Our tensioner and puller equipment are designed to ensure a seamless and safe tension stringing operation.

Selecting the correct cable pulling winch is crucial for project success and safety. Key factors to consider include the maximum pulling force required, the cable diameter and length, and the specific type of project (e.g., utility, telecom, mining). It is essential to choose a winch with a pulling capacity that exceeds the calculated maximum tension to prevent equipment failure. Our range of hydraulic and electric cable winches offers various pulling forces to meet the demanding requirements of any underground cable laying project.

The safe handling of cable drums is paramount. When using cable drum jacks and stands, always ensure they are placed on a firm, level surface and are rated for the combined weight of the drum and cable. The drum shaft must be centered and the jacks placed as close to the drum flanges as possible for maximum stability. It is also a best practice to uncoil the cable from the bottom of the drum to prevent the entire assembly from becoming unstable. Our hydraulic and mechanical drum stands are designed with robust safety features to ensure a secure and efficient operation.

The proper sizing of grooves on bullwheels and sheaves is vital to prevent conductor damage, particularly in high-tension stringing. The groove diameter must be large enough to accommodate the conductor without causing stress or deformation. The lining of the grooves should also be made from a durable polymer to protect the conductor's surface. Incorrect groove sizing can lead to conductor scuffing, bending, or damage to the outer strands, which can affect the conductor's long-term performance. Our equipment is manufactured to strict industry standards, featuring precision-machined, polymer-lined bullwheels and sheaves to protect your valuable conductors.

Safety is our top priority. The key best practices for underground cable laying include:

• Thorough Planning: Before any excavation, a comprehensive utility detection and mapping process must be performed using ground-penetrating radar (GPR) or other locators to identify existing underground services.

• Proper Trench Design: Trenches must be of sufficient depth and width, with stable walls, to prevent collapse.

• Personal Protective Equipment (PPE): All workers must use appropriate PPE, including hard hats, insulated gloves and boots, and high-visibility clothing.

• Correct Equipment Usage: Utilize specialized equipment like cable drum jacks, cable rollers, and pulling winches with tension monitoring systems to ensure that the maximum pulling tension is not exceeded, preventing cable damage and ensuring worker safety.

• Grounding and Bonding: Proper grounding and bonding are crucial to prevent electrical shock.

• Post-Installation Testing: Conduct thorough electrical testing, such as insulation resistance and continuity testing, before energizing the cables.

The required depth for burying electrical cables in a trench varies by region and voltage level. However, a general guideline is as follows:

• Low Voltage (LV) cables (< 1kV): Typically buried at a minimum depth of 450-750 mm (18-30 inches).

• Medium/High Voltage (MV/HV) cables (> 1kV): Buried deeper, typically 750-1200 mm (30-48 inches). Under roads or driveways, depths are often increased, and cables are always installed within protective ducts. The trench should also have a bedding layer of fine soil or sand to protect the cable from sharp rocks and provide a good thermal environment.

Preventing cable damage is critical for the long-term reliability of the power line. We recommend the following:

• Using the Right Tools: Employ cable rollers to guide and support the cable, minimizing friction and abrasion.

• Controlled Pulling: Use hydraulic pulling winches with tension monitoring devices to ensure the pulling force remains within the manufacturer's specified limits. Over-tensioning can stretch and damage the cable's conductors or insulation.

• Maintaining Bending Radius: Never bend a cable tighter than its specified minimum bending radius. We offer a wide range of cable laying tools to assist in maintaining these crucial parameters.

• Appropriate Lubricants: Use specialized lubricants to reduce friction when pulling cables through ducts or conduits.

Our company, Ningbo Changshi, specializes in providing the comprehensive equipment required for these projects. The essential tools for underground cable laying include:

• Cable Drum Stands and Jacks: To safely lift and support heavy cable drums.

• Hydraulic Pulling Winches: For controlled, powerful pulling of cables.

• Cable Rollers and Sheaves: For guiding cables along the trench or into ducts.

• Duct Rodders and Cable Pulling Grips: To pull cables through conduits.

• Trenchers or Excavators: For digging the trench itself.

• Warning Tape and Cable Covers: To provide a visual and physical barrier against future excavation damage.

The best practices for temporary surface cable installation focus on safety and protection. We recommend using durable cable protection ramps and covers to shield the cables from physical damage and create a safe pathway for pedestrians and vehicles. It is crucial to select equipment that can withstand the weight of the anticipated traffic. All cables should be clearly marked and laid in a way that minimizes trip hazards. We offer a variety of cable protection solutions designed for different environments, from pedestrian walkways to heavy-duty vehicle crossings.

Protecting surface-laid cables requires a multi-faceted approach. To prevent damage from vehicles, use heavy-duty cable protectors or ramps that can support the weight of the traffic. For pedestrians, use low-profile cable covers to minimize trip hazards. Environmental protection is also key. Using UV-resistant and waterproof materials for cable covers helps prevent degradation from sun and rain. Our product catalog includes a range of specialized equipment, such as modular cable ramps and cord covers, that are engineered to provide superior protection in various conditions.

The primary safety risks include tripping hazards, cable damage, and potential for electrical shock. Mitigation is achieved through meticulous planning and the use of the right equipment.

• Tripping Hazards: Use high-visibility, clearly marked cable covers and ramps to guide foot traffic safely over the cables.

• Cable Damage: Select robust protection equipment to shield cables from being crushed, cut, or abraded.

• Electrical Shock: Ensure all cables are properly insulated and inspected before and after installation. The use of our cable protection systems helps maintain the integrity of the cable sheath, reducing the risk of a breach.

As a leading manufacturer, Ningbo Changshi provides a comprehensive suite of equipment for temporary cable management and protection. Our offerings include:

• Cable Protection Ramps: Designed for heavy-duty applications to protect cables from vehicles.

• Cable Covers: Low-profile solutions for pedestrian walkways and light traffic areas.

• Cable Trays and Supports: For elevated cable management, keeping them off the ground entirely in certain scenarios.

• Cable Ties and Straps: For bundling and securing cables to prevent tangles and provide a neat appearance.

The most efficient methods for laying underground cables depend on the project's scale and environment. For traditional trenching, the process involves excavating a trench, placing the cable, and then backfilling it. We supply a wide range of cable rollers, cable jacks, and drum stands that are essential for handling and positioning the cable drum safely and efficiently. For modern trenchless methods like Horizontal Directional Drilling (HDD), efficiency is achieved by pulling the cable through a pre-drilled borehole, minimizing surface disruption. Our company provides specialized equipment like cable pushers, swivel connectors, and pulling grips designed to make these complex operations seamless and safe.

Ensuring the safety and integrity of cables is paramount. This involves meticulous planning and the use of the right equipment to prevent damage. Key measures include:

• Tension Control: Using hydraulic puller-tensioners and winches to maintain a constant, controlled tension during the pull, preventing stretching or snapping of the conductor.

• Friction Reduction: Utilizing a variety of cable rollers and guides to reduce friction as the cable is pulled through ducts, trenches, or bends.

• Proper Handling: Employing cable jacks, drum stands, and cable trailers to securely manage heavy cable drums, preventing accidental unwinding or drops. Our equipment is designed and manufactured to meet high-quality standards, guaranteeing the integrity of your cables throughout the installation process.

Cable-pulling winches and hydraulic puller-tensioners are the core machinery in large-scale cable laying operations. A puller-tensioner is used in overhead line stringing and underground cable laying to maintain precise control over the conductor's tension. The hydraulic system provides a smooth, controlled pull and braking, which is critical to avoid over-stressing the cable. The cable-pulling winch provides the pulling force to guide cables through conduits, ducts, or trenches. Our equipment is known for its reliability and precision, ensuring a safe and damage-free installation.

• Traditional Trenching:

  • Method: Excavating a trench, laying the cable, and backfilling.

  • Pros: Cost-effective for short distances and open areas.

  • Cons: Causes significant surface disruption, can be labor-intensive, and is not suitable for crossing major obstacles like roads or rivers.

• Trenchless (HDD):

  • Method: Drilling a pilot hole along a planned path and then pulling the cable through the enlarged hole.

  • Pros: Minimal surface disruption, ideal for urban areas, and can navigate under obstacles.

  • Cons: Requires specialized equipment and skilled operators, and is more complex and potentially more expensive for shorter, simple runs.

We offer a full range of equipment to support both methods, providing you with a single source for all your cable laying needs.