The Current Rating mentioned in the below links are under Operating Conditions :
Maximum continuous operating conductor-temperature = 90°C
Standard ground temperature = 30°C
Ambient air temperature = 40°C
Thermal Resistivity of soil =150°C cm/watt
Depth of laying (for cables laid direct in ground) = 75 cms
METHOD OF INSTALLATION :
Multi core cables installed independently.
Single Core Cables : a) Three cables laid in a trefoil touching each other. b) Three cables laid flat touching.