Question

State the procedure for laying / installation of underground cable.

Answer 1

1) Direct laying Cable: or Trench laying method:

Procedure:
 For laying of a cable trench about 1.5m deep and 0.5m wide is made along the cable
route.
 A layer of 10 cm thickness of soft soil is spread throughout the cable route in trench.
 The cable is laid on this soft soil (bed)
 A wall of bricks (concrete cover) is provided on either side or top of cable along the
length of cable for better mechanical protection.
 Another layer of soft sand, about 10 cm thicknesses is spread throughout its cable length.
 Refill the remaining trench with the help of remaining soil up to ground level.
 While crossing roads (public-crossing) cable is laid through cement pipe or DWC pipe, instead of bricks for better mechanical protection.
 When more than 1 cable is to be laid in the same trench, then minimum 30 cm spacing is
provided between 2 cables and gap is filled by sand.
 The spacing is kept between 2 cables to reduce the effect of mutual heating and also fault
occurring on one cable does not damage the adjacent cable.
 Only armored cables are used in this method.