hence corrective action is equally difficult for maintenance personnel.
vi. Since the cables are underground in tunnels, hence no high level of
engineering skill is required. Underground cable Laying system do not create
any hurdle for roads, buildings, equipment, water and air pipe lines, plant
structures etc.
vii. Underground cable Laying system do not tender any hurdle for shifting of
equipment, erection of structures, crane movement cable Laying, tray
erection etc. however facilitates in project task for welding supplies hence
this acts as a booster for project activities.
viii. Provision for future expansion should be considered at initial stage because
flexibility of further expansion is very difficult in underground cable Laying.
Expansion becomes very costly too due to underground configuration. Civil
foundations for equipment, structures, etc. become biggest hurdle for future
expansion.
ix. Dust deposition on cables does not take place in case of underground
cable Laying system. Because cables are not exposed to environment
hence no need regular cleaning of cables in trays.
x. Ambient temperature of underground cables is more than 10 deg C lower
than overhead cables. As a result of it, life of cables is improved along with
increased current currying capacity.
6.3 Technical Comparison:
S.N. Cable Tunnels Cable Galleries- The cable tunnels underground activities hence
do not create any disturbance in project
work like crane movement, equipment
and structure erections etc. but tenders facility
of power supply to welding machine and
power tools resulting in boosting of project
activities.
There is obstacle in project
work for crane movement
due to overhead installation.
It becomes hurdle in crane
movement, shifting of equipment,
erection of structure which result
delays the project activities.
2 Electrical work can be started in parallel with
mechanical erection during project stageElectrical work is not possible along
with mechanical erection due to
open structures.- Cables remain safe and secure from
mechanical damages which may take place
during construction activities.
Cables are not safe from
mechanical damages which may take
place during construction activities.- Ambient temperature of underground cables
is lower because these are not direct expose
to sun light hence lower deration factor is
considered due to low tunnel temperature.
Therefore, a cable of specific cross section area
is designed for higher current rating.
As the cables remain direct expose
to sun light which results higher
ambient temperature. Hence higher
deration factor is considered due to
high ambient temperature.Therefore,
a cable of specific cross section is
designed for lower current rating.