The correct answer is: D. All of the above
Direct laying is the simplest and most common method of laying underground cables. It involves burying the cables directly in the ground, without any additional protection. This method is relatively inexpensive and easy to implement, but it is not suitable for all types of cables or all types of terrain.
Draw-in-system is a method of laying underground cables that uses a pulling cable to pull the cables through a pre-installed conduit. This method is more expensive than direct laying, but it is more versatile and can be used in a wider range of applications.
Solid system is a method of laying underground cables that uses a solid steel pipe to protect the cables. This method is the most expensive, but it is also the most durable and can be used in the most demanding applications.
Here is a more detailed explanation of each option:
- Direct laying is the simplest and most common method of laying underground cables. It involves burying the cables directly in the ground, without any additional protection. This method is relatively inexpensive and easy to implement, but it is not suitable for all types of cables or all types of terrain. For example, direct laying is not suitable for cables that are sensitive to moisture or that may be damaged by roots or other underground obstructions.
- Draw-in-system is a method of laying underground cables that uses a pulling cable to pull the cables through a pre-installed conduit. This method is more expensive than direct laying, but it is more versatile and can be used in a wider range of applications. The pulling cable is typically made of steel or nylon, and it is strong enough to pull the cables through the conduit without damaging them. The conduit can be made of a variety of materials, including PVC, steel, and concrete.
- Solid system is a method of laying underground cables that uses a solid steel pipe to protect the cables. This method is the most expensive, but it is also the most durable and can be used in the most demanding applications. The steel pipe is typically buried in the ground, and it provides a protective barrier for the cables. This method is often used for cables that are located in areas with a high risk of damage, such as areas with heavy traffic or that are prone to flooding.