Answer from Ningbo Changshi: Lubrication is not just a helpful accessory; it's a critical component of any underground cable pull. It is a fundamental strategy for managing friction, which is the leading cause of cable damage during installation.

A proper, water-based lubricant provides a thin, slick film between the cable jacket and the conduit wall. This dramatically reduces the coefficient of friction. The benefits of this reduction are:

• Reduced Pulling Tension: By lowering friction, the required pulling force drops significantly. This directly protects the cable from over-stressing and micro-damage to its internal conductors and insulation.

• Extended Pull Lengths: A lower friction coefficient allows for much longer continuous pulls, reducing the number of costly and time-consuming splices required in a project.

• Protection for Equipment: Less tension on the line means less strain on the pulling winch and its components, extending the service life of the equipment.

We supply a range of high-performance lubricants specifically formulated to work with our equipment and various cable types, ensuring maximum efficiency and safety.

Answer from Ningbo Changshi: A successful and safe cable pulling project, whether for overhead or underground lines, requires a system of interconnected tools, not just a single piece of equipment. We categorize these essential tools into three main groups that we supply as a one-stop provider:

• Tension and Pulling Machines: These are the core of the operation. For large-scale projects, this includes powerful hydraulic pullers and tensioners that provide the controlled force needed to string conductors or pull underground cables. For smaller jobs, this may include winches or fiber optic cable blowers.

• Cable Handling Equipment: This category includes all the support equipment that manages the cable itself. This includes cable reel trailers or drum jacks to safely transport and dispense the cable, as well as cable rollers and guides to support the cable and reduce friction along the route.

• Pulling Accessories and Safety Tools: This is a diverse but crucial group. It includes all the components that connect the pulling machine to the cable. This covers cable pulling socks (grips) to securely attach to the cable, swivels to prevent twisting, and tension meters to monitor the pulling force in real-time. This category also includes vital safety accessories like conductor clamps and ground sets.

A professional contractor understands that each of these categories of tools must work together seamlessly to ensure the job is done efficiently and without damaging the cable.

Answer from Ningbo Changshi: The correct procedure for a winch-based cable pull involves careful planning and a methodical execution to ensure both safety and the integrity of the cable. The key steps are:

• 1. Site & Equipment Preparation: Before you begin, the winch must be securely anchored and leveled in line with the pull. Ensure the pulling line has at least five full wraps on the winch drum to prevent slippage and damage. At the feeding end, the cable drum stands or jacks should be positioned to allow the cable to feed smoothly into the conduit.

• 2. Rigging the Pull: Attach the pulling line to the cable using a properly sized cable pulling grip (or sock). A swivel must be used between the grip and the pulling line to prevent the cable from twisting under tension. A tension meter is then rigged in-line to provide real-time monitoring of the pulling force.

• 3. Controlled Operation: The winch should be operated smoothly and consistently. Avoid sudden starts or stops that can create dangerous shock loads. Monitor the tension meter at all times to ensure the pulling force remains within the cable manufacturer's specified limits.

• 4. Communication and Safety: Maintain clear communication between the winch operator, the cable feeder, and any personnel along the route. Keep all hands and body parts clear of the moving line, and never step over a line under tension. A safe distance should be maintained by all personnel from the winch and the pulling line.

Adhering to this professional procedure minimizes risk and ensures a successful installation.

Answer from Ningbo Changshi: While many tools and principles are similar, there are key differences in equipment design and application for overhead and underground projects.

• Overhead Transmission Line (OHTL) Tools: The main challenge is managing tension over long, open spans. Hydraulic tensioners and pullers are used in pairs to precisely control the sag and tension of the conductor. Specialized stringing blocks are used to guide the conductor from tower to tower, and anti-twist devices are critical for preventing conductor damage.

• Underground Cable Laying Tools: The primary challenges are friction and navigation through confined spaces. The tools used focus on reducing friction and providing consistent force. This includes a variety of cable rollers (straight line and corner rollers), duct rods, and lubricants. For heavy cables, winches and bullwheel pullers are used to provide the pulling force, and the pulling route is carefully planned to avoid over-tensioning.

Despite these differences, our comprehensive product range covers both applications. For example, our cable pulling socks and swivels are designed with the versatility to be used in both environments, providing a true one-stop supply solution for all your project needs.

Answer from Ningbo Changshi: The choice between a hydraulic and an electric winch depends on the specific demands of the project. However, for most heavy-duty and continuous cable pulling applications in our industry, hydraulic winches are the preferred choice due to their superior performance characteristics:

• Continuous Duty and Power: Hydraulic winches are designed for sustained, heavy-duty use without the risk of overheating that is common with electric motors. They can provide consistent pulling force for long, continuous pulls, making them ideal for long-distance underground cable runs or overhead conductor stringing.

• Greater Torque and Load Capacity: Hydraulic systems can generate immense torque, which translates directly into superior pulling power. They are capable of handling significantly heavier loads with greater ease and efficiency than comparably sized electric winches.

• Failsafe Braking: Our hydraulic winches feature an automatic, spring-applied, hydraulically released braking system. This failsafe brake automatically engages and holds the load securely in the event of a power loss or hydraulic pressure drop, providing an essential layer of safety.

• Durability in Harsh Environments: The closed hydraulic system is less susceptible to damage from water, dirt, and mud, making hydraulic winches more reliable in the challenging conditions of a construction site.

This reliability and power make our hydraulic winches an indispensable part of a professional cable installation crew's toolkit.

Answer from Ningbo Changshi: It might seem like a minor detail, but a high-quality lubricant is one of the most cost-effective tools for a successful cable pull. Its importance cannot be overstated.

• Friction Reduction: Lubricants drastically reduce the coefficient of friction between the cable jacket and the inner wall of the conduit. This directly lowers the pulling tension required to install the cable, which in turn reduces the risk of over-tensioning and damaging the cable.

• Time and Labor Savings: Lower tension means a faster, smoother pull with less stress on the equipment and fewer man-hours.

• Equipment Preservation: Using lubricant lessens the strain on the pulling machine, extending its service life and reducing the need for maintenance.

Similarly, cleaning tools like mandrels and brushes are essential. They are used to clear debris from the conduit before a pull. Any dirt, rocks, or even small irregularities can increase friction and risk damaging the cable, making the cleaning process a vital preparatory step. We offer a full range of high-performance lubricants and cleaning tools to protect your investment in the cable and equipment.

Answer from Ningbo Changshi: Safety is the paramount concern on any job site. When using a winch, specific precautions must be taken to prevent injury and equipment failure. The most important safety measures include:

• Never Exceed the Rated Capacity: Always match the winch's rated pulling capacity to the demands of the job, and remember that this capacity decreases with each layer of rope on the drum. A safety factor of at least 1.5 times the expected load is a standard industry best practice.

• Proper Anchoring: The winch's anchoring system must be secure and rated to withstand the maximum expected pulling load. Any movement or slippage of the winch during the pull is extremely dangerous.

• Watch for Over-Tensioning: Over-tensioning can cause the pulling line or cable to snap, creating a dangerous whip-like projectile. Use a tension meter and never rely on visual estimation alone.

• Protect the Cable: Use an anti-twist swivel between the pulling line and the cable to prevent internal damage from rotation.

• Maintain Clear Lines of Sight: Ensure the operator has a clear view of the pulling operation or is in constant communication with a spotter. Use a remote control to allow the operator to stand at a safe distance from the winch.

• Wear Proper PPE: Always wear personal protective equipment (PPE), including gloves, safety glasses, and hard hats.

By prioritizing these safety measures, we can ensure that every project is completed without incident, protecting both personnel and valuable equipment.

Answer from Ningbo Changshi: The primary difference lies in how they handle the pulling rope and manage tension. A capstan winch uses a rotating drum where the operator manually wraps and controls the rope. It's excellent for applications where you need to accommodate long, unlimited lengths of rope and can be operated by hand with precise control.

A bullwheel winch, on the other hand, utilizes a grooved bullwheel (or several bullwheels) to capture and apply force to a continuous pulling rope. The pulling rope is stored on a separate storage drum. This design is ideal for high-tension, long-distance pulls because the bullwheel maintains a consistent pulling force without the operator having to manually wrap the rope. For heavy-duty cable pulling in overhead or underground projects, a bullwheel winch is the superior choice. It provides a more consistent, powerful, and safer pulling force over long distances, which is a key feature of our hydraulic puller-tensioners.

Answer from Ningbo Changshi: A professional underground cable laying project requires a systematic approach and a suite of interconnected tools. We see the fundamental toolkit as a four-part system:

• 1. Pulling Machines: This is the core of the operation. Depending on the size of the project, this can be a trailer-mounted hydraulic winch for heavy-duty power cables or a more compact winch for smaller communication cables. These machines provide the controlled and consistent pulling force necessary for long distances.

• 2. Cable Management Equipment: This category includes everything that handles and guides the cable. Key items are cable reel stands or trailers to safely dispense the cable and a variety of cable rollers to support the cable along the route and reduce friction at bends and entry points.

• 3. Duct Preparation and Access Tools: Before pulling, the conduit must be cleared. Tools like duct rods (often made of fiberglass), duct cleaners, and mandrels are used to prove the conduit is clear of obstructions. For difficult access points like manholes, specialized manhole cable guides are used to protect the cable sheath from damage.

• 4. Connection and Monitoring Accessories: This group includes the smaller but critical components. Cable pulling socks (grips) securely connect the pulling line to the cable. A swivel is essential to prevent the pulling line from twisting the cable. Most importantly, a tension meter is used to monitor the pulling force in real-time, preventing the cable from being overstressed.

Our "one-stop supply" model is designed to provide all of these tools, ensuring a complete and professional solution for any underground project.

Answer from Ningbo Changshi: Choosing the correct pulling capacity is critical for both safety and equipment longevity. A common mistake is to select a winch with a capacity equal to the cable's weight. The correct approach is to consider all factors that contribute to the total pulling force.

You should select a winch with a rated line pull capacity that is at least 1.5 times the calculated total pulling force of your specific project. This safety margin accounts for:

• Friction: The coefficient of friction between the cable and the conduit/sheaves.

• Bends and Slopes: Each turn or incline exponentially increases the pulling tension.

• Length of the Pull: Longer pulls build up more cumulative tension.

• Number of Layers on the Drum: Winches lose pulling power with each successive layer of rope wrapped around the drum.

We recommend using a tension calculation tool to accurately determine the required pulling force for your specific job. Our sales engineers are also available to assist with these calculations to ensure you choose the safest and most efficient winch for your needs.

Answer from Ningbo Changshi: Safety is our top priority, and modern winches are equipped with advanced features to protect both the operator and the cable. When evaluating a winch, look for these critical features:

• Automatic Overload Protection: This system automatically shuts down the winch if the pulling tension exceeds a pre-set maximum. It's a crucial feature that prevents over-tensioning and damaging the cable.

• Braking System: A reliable braking system is essential. Our winches feature a failsafe braking system that automatically engages if power is lost, preventing the load from running away.

• Bullwheel Diameter: A larger bullwheel diameter reduces the stress on the cable and the pulling rope, extending their lifespan and ensuring a smoother pull.

• Remote Control: Many of our winches are equipped with a wired or wireless remote control. This allows the operator to control the pull from a safe distance, away from the moving rope and the direct line of tension.

• Integrated Data Logger: Our advanced models include an integrated tension meter and data logger, which provides a real-time display of the pulling force and records the data for quality assurance and compliance reporting.

By investing in a winch with these features, you are investing in the safety of your crew and the integrity of your entire project.

Answer from Ningbo Changshi: The professional process for pulling cable into an underground conduit is methodical to ensure safety and prevent damage to the cable. While specific steps may vary, the core process includes:

• 1. Site and Duct Preparation: Before any pulling begins, the route must be inspected. The conduit or duct is cleared of debris using a brush and mandrel to ensure a smooth path. A pilot line, often a durable nylon rope, is then "fished" through the duct using a blowing or vacuum system to verify the path is clear and to prepare for the main pull.

• 2. Equipment Setup: The cable reel trailer or drum stands are set up at the feed end of the conduit. The pulling winch, often a trailer-mounted hydraulic winch, is positioned at the receiving end of the run. A tension meter is installed on the pulling line to monitor the force in real-time.

• 3. Pulling and Lubrication: The pulling line is attached to the cable using a pulling grip and a swivel to prevent twisting. As the pulling winch begins to operate, cable rollers and guides are placed at the entry point and at any bends to support the cable and reduce friction. A high-quality, approved lubricant is consistently applied to the cable as it enters the duct to minimize pulling tension and prevent sidewall friction damage.

• 4. Monitoring and Completion: The entire process is monitored by a team using communication systems to ensure a steady, controlled pull. The tension meter data is logged to provide a verifiable record that the cable was installed within its manufacturer-specified limits. Once the cable is pulled through, it is secured and prepared for termination or splicing.

Our one-stop supply model provides all the necessary equipment, from the winches and trailers to the rollers, lubricants, and pulling accessories, to execute this process flawlessly.

Answer from Ningbo Changshi: Underground cable pulling presents unique challenges that require careful planning and specialized equipment. The most significant challenges are:

• Friction and Tension Buildup: The primary challenge is the high friction created as a heavy cable is pulled through a conduit, especially around multiple bends. This friction can lead to a rapid increase in tension, risking damage to the cable.

  • Solution: Overcome this with meticulous route planning to minimize bends, the use of a high-quality lubricant, and most importantly, a controlled pulling machine with a tension meter to ensure the force never exceeds the cable's safe limit.

• Duct Integrity and Obstructions: Conduits may have unseen irregularities, sharp edges, or debris that can snag the cable and cause damage.

  • Solution: A thorough pre-pull cleaning and proving process using mandrels and brushes is essential. This ensures the duct is clear before the expensive cable is even on-site.

• Complex Terrain and Lack of Space: Urban and industrial projects often involve manholes and conduits in tight, confined spaces, making equipment setup difficult.

  • Solution: We offer compact, high-performance equipment designed for these challenging environments, such as hydraulic winches with smaller footprints and a variety of rollers and guides to handle tight bends.

Proper planning and using the right tools are key to turning these challenges into successful project outcomes.

Answer from Ningbo Changshi: Tight bends are one of the most challenging aspects of underground cable pulling, as they are a major source of friction and potential cable damage. To navigate them, we recommend using a combination of specialized tools:

• Corner Cable Rollers: These are specifically designed with a curved frame and multiple rollers to guide the cable smoothly through 90-degree or other sharp turns in a manhole or vault. They protect the cable's jacket by maintaining a larger bending radius than the tight corner of the conduit itself.

• Fiberglass Duct Rods: For initially installing a pilot line in a conduit with multiple bends, a fiberglass rod is invaluable. These rods are semi-rigid and flexible enough to be pushed through the curves of the duct, making them perfect for fishing a line where a vacuum blower might not be able to.

• Lubrication: While not a tool in the traditional sense, using a high-performance, water-based cable pulling lubricant is a non-negotiable part of the process. It drastically reduces friction at bends and throughout the run, significantly lowering the required pulling tension and protecting the cable.

Using these specialized tools together ensures that the cable safely and smoothly transitions through all bends in the underground route.

Answer from Ningbo Changshi: The two primary methods for underground cable installation are pulling and blowing, and each has distinct advantages and applications.

• Cable Pulling (Winch Method): This is the most common method for installing heavy, large-diameter power cables. A winch pulls the cable through a conduit using a pre-installed pulling line. This method is ideal for long distances, heavy cables, and challenging routes with multiple bends because the hydraulic winch provides a controlled and consistent pulling force to overcome friction. Pulling is the standard for most utility-grade power cable installations.

• Cable Blowing (Blower Method): This method uses a high-pressure air stream to float and propel a lightweight cable (such as fiber optic or small communication cables) through a conduit. This is an excellent choice for lightweight, flexible cables over straight runs because it's fast and generates very little tension, minimizing the risk of damage to sensitive cables.

We provide a wide range of hydraulic winches and pulling accessories for the pulling method, which is our core specialization for heavy-duty power line projects. Choosing the right method depends on the project scale, cable type, and route complexity, and our engineers are available to provide expert advice on the best equipment for your specific job.

Answer from Ningbo Changshi: A modern underground cable pulling machine, a core component of our product line, is designed for both power and efficiency. Beyond simply providing a pulling force, a professional machine includes several key features that ensure safety and precision:

• Bullwheel Design: Our machines feature a hydraulic bullwheel which provides a constant pulling force and speed. Unlike drum winches where tension varies as the rope layers build, a bullwheel ensures smooth and consistent tension, protecting the cable from stress.

• Integrated Tension Meter: A digital or analog dynamometer is crucial. It provides real-time feedback on the pulling tension, allowing the operator to stay within the cable manufacturer's specified limits. Many of our models include a data logger to record this information for quality assurance and project documentation.

• Automatic Overload Protection: This is a vital safety feature. The machine automatically shuts down if the pulling tension exceeds a pre-set limit, preventing over-tensioning that can damage the cable.

• Trailer-Mounted Portability: Most of our machines are mounted on a heavy-duty trailer. This design allows for easy transport between job sites and provides a stable platform for safe operation, eliminating the need for complex rigging or anchoring.

• Controlled Payout and Remote Operation: Modern machines offer controlled payout to prevent the cable from back-spinning or snagging. They often include wired or wireless remote controls, allowing the operator to stand in a safe, visible location away from the pulling line.

These features make our machines a complete, professional solution for any underground project.

Answer from Ningbo Changshi: Selecting the correct machine size is a critical decision that impacts safety, efficiency, and project cost. The primary factor is not the size of the cable itself, but the total pulling force required. To make the right choice, consider the following:

• Cable Weight and Length: The longer and heavier the cable, the more force will be required. This is the base load of the pull.

• Friction: The biggest variable is friction from the conduit or duct. Rough surfaces, small conduit diameters, and contaminants will dramatically increase the required force.

• Bends and Elevation Changes: Every bend, incline, or decline in the cable route adds a significant multiplier to the pulling tension. A single 90-degree bend can exponentially increase the required force.

• Safety Factor: Always choose a machine with a rated capacity that is at least 1.5 times the maximum calculated pulling tension. This provides a crucial safety margin to account for unforeseen conditions and protects the cable from being overstressed.

For complex projects, we recommend a detailed pulling study. Our sales engineers can assist you in calculating the required tension based on your project's specific parameters, ensuring you get a machine that is both powerful enough and safely rated for the job.

Answer from Ningbo Changshi: While our large, trailer-mounted machines are ideal for major projects, we also recognize the need for specialized tools for challenging environments. Portable and compact cable pullers offer unique benefits for confined spaces like urban manholes, utility vaults, and congested substations.

• Maneuverability: These machines are designed with a smaller footprint and are often skid-mounted or feature compact designs that can be moved into tight spaces where a trailer-mounted unit cannot go.

• Efficiency: For shorter pulls or runs with multiple access points, a portable puller can be quickly set up and moved to the next location, significantly improving efficiency.

• Ergonomics and Safety: Portable pullers are often designed with features that reduce manual labor and improve safety in cramped conditions, such as adjustable arms to align with duct entrances and remote controls to keep the operator out of the direct line of tension.

Our range of underground tools includes these compact pullers, ensuring we can provide a safe and effective solution for every project, regardless of its scale or spatial limitations.

Answer from Ningbo Changshi: While a lower initial price can be tempting, purchasing a used cable pulling winch carries significant risks that can lead to higher costs and project delays. The most critical risks include:

• Unknown History and Condition: A used winch may have been overloaded, improperly maintained, or operated in a harsh environment. Without a complete service history and an independent technical inspection, you are purchasing a machine with an unknown past, and potential hidden internal damage to hydraulic components, gears, or the engine.

• Reduced Safety Features: Older, used models may lack modern safety features such as automatic overload protection, integrated tension recorders, and advanced braking systems. The absence of these features increases the risk of damaging the cable and poses a serious safety hazard to the operating crew.

• Increased Maintenance and Repair Costs: The immediate savings on a used machine can quickly be erased by unexpected repairs. Worn-out parts, fluid leaks, and component failures are common in older equipment and can lead to costly downtime.

• No Warranty or Support: A used winch typically comes with no manufacturer's warranty. If a critical component fails, you are responsible for the full cost of the repair, and finding replacement parts for older models can be difficult and time-consuming.

For these reasons, a new, certified machine from a reputable manufacturer like Ningbo Changshi offers a far more reliable and secure investment.

Answer from Ningbo Changshi: When considering a used cable puller, a thorough inspection is crucial to mitigate risk. We recommend following this professional checklist:

1. Request Full Documentation: Ask for a complete maintenance log, operating hours, and a record of any previous repairs. A seller who can provide this documentation demonstrates a history of proper care.

2. Inspect the Hydraulics and Engine: Check for any signs of hydraulic fluid leaks around the hoses, fittings, and cylinders. A professional mechanic should inspect the engine's condition and performance.

3. Examine the Winch Drum/Bullwheel: Look for any signs of excessive wear, damage, or deformation. The bullwheel's grooves should be in excellent condition to prevent damage to the pulling rope.

4. Test All Safety Features: If possible, test the automatic braking system, overload protection, and any emergency stop buttons. These are non-negotiable for safe operation.

5. Review the Frame and Welds: Inspect the winch's frame for any signs of cracking, stress fractures, or poorly executed repairs. The structural integrity is paramount to safety.

While this inspection can reduce risk, it cannot reveal the machine's full history or future reliability. This is where the advantage of buying new becomes clear—you get a machine with a full warranty, guaranteed performance, and a clear path to parts and service support.