Page 371 - IRSEM_Main Book

(f) During excavation, the soil of the trenches should not be thrown on the ballast.
The soil should be thrown by the side of the trenches away from the track.

(g) In places where cables to be laid within 1 meter from sleeper end, digging
beyond 0.50 meter shall be done in the presence of an official from
Engineering Department, and the laying of the cable and refilling of trench
should be done with least delay.

(h) The work shall be supervised at site personally by an official of the Signal and
Telecommunication Department not below the rank of a JE/SSE (Signal).

Section 3: Cable Laying in RE Area

15.3.1 Only unscreened approved type underground cables shall be used for
signalling purposes.

The following precautions shall be taken:
(a) The cable shall be so laid that it is not less than one meter from the nearest
edge of the mast supporting the catenary or any other live conductor,
provided the depth of the cable does not exceed 0.5 meters. When the
cable is laid at a depth greater than 0.5 meters, a minimum distance of
3 meters between the cable and the nearest edge of the O.H.E structure
shall be maintained. If it is difficult to maintain these distances, the cable
shall be laid in DWC-HDPE/Concrete Ducts or any other approved means
for a distance of 3 meters on either side of the Mast. When so laid, the
distance between the cable and the mast may be reduced to 0.5 meters.
These precautions are necessary to avoid damage to the cable in the event
of the failure of an overhead insulator.

(b) In the vicinity of traction sub stations and feeding posts, the cable shall be
at least one metre away from any metallic part of the O.H.E and other
equipment at the substation, which is fixed on the ground, and at least one
metre away from the substation earthing. As far as possible, the cable shall
be laid on the side of the track opposite to the feeding post. In addition, the
cable shall be laid in concrete or DWC-HDPE pipes (approved type)/Split
RCC pipes or other approved means for a length of 300 meters on either
side of the feeding point.

(c) In the vicinity of the switching stations, the cable shall be laid at least one
metre away from any metallic body of the station, which is fixed in the
ground, and at least 5 meters away from the station Earthing. The distance
of 5 meters may be reduced to one metre provided the cables are laid in
concrete pipes/DWC-HDPE-pipes of approve type/ducts or any other
approved means.

(d) Where an independent Earth is provided for an O.H.E structure, i.e. where
the mast is connected to a separate Earth instead of being connected to
the rail, the cables shall be laid at least one metre away from the Earth.

(e) Where there are O.H.E structures along the cable route, the cable trenches
shall as far as possible, be dug not less than 5.5 meters away from the
centre of the nearest Track.

Chapter 15: Cables Page 319 of 535