Which of the following is NOT a disadvantage of the direct laying method?

Direct Laying Of Underground Cables

The cables to be laid using this method must have a serving of bituminized paper and hessian tape so as to provide protection against corrosion and electrolysis.

The direct laying procedure is as follows:

• A trench of about 1.5 meters deep and 45 cm wide is dug.
• Then the trench is covered with a 10 cm thick layer of fine sand.
• The cable is laid over the sand bed. The sand bed protects the cable from moisture from the ground.
• Then the laid cable is again covered with a layer of sand about 10 cm thick.
• When multiple cables are to be laid in the same trench, a horizontal or verticle spacing of about 30 cm is provided to reduce the effect of mutual heating. Spacing between the cables also ensures a fault occurring on one cable does not damage the adjacent cable.
• The trench is then covered with bricks and soil to protect the cable from mechanical injury.

Advantages

• Simple and cheap method.
• The heat generated in cables is easily dissipated in the ground.​

Disadvantages

• ​Alterations in the cable network are not easy.
• Maintenance cost is higher.
• Identifying the location of a fault is difficult.
• This method can not be used in congested areas such as metro cities where excavation is too expensive.