Following factors considered for the selection of the cable.
a. System voltage.
b. Condition of installation.
c. Continuous current to be carried.
d. Maximum operating conductor temperature (70°).
e. Ambient air temperature (40°).
f. Thermal resistivity of soil.
g. Depth of laying.
h. Short circuit current. Ish = Ka / (t/2). Where ‘K’ is constant (K = 109 for copper cables), ‘a’ is area and ‘t’ is time duration of short circuit in seconds.
