The importance of "Ambient Temperature based Correction Factor," on the conductor sizing

[Genghiz]

Introduction : 

Wiring systems shall be selected and erected so as to be suitable for any temperature between the highest and the lowest local ambient temperature and to ensure that the limiting temperature in normal operation and the limiting temperature in case of a fault will not be exceeded. NOTE “Limiting temperature” means maximum continuous operating temperature.

Current Carrying Capacity:

The current to be carried by any conductor for sustained periods during normal operation shall be such that the temperature limit of the insulation is not exceeded. This requirement is fulfilled by application of Table 52.1, for the types of insulation given in this table.

Maximum operating temperatures for types of insulation:

The table 52.1 of the IEC standard is given here, and this explain the 'maximum operating temperature for different types of insulation.

Correction Factor based on Temperature (Air):

For the Correction Factor based on Temperature; while the cable installation is present in AIR, the following table should be considered. This has a classification of correction factors based on the different insulations (PVC, XLPE) as well.

Kindly be noted that, the correction factor for the ambient air temperature of 30 *C can be considered as one (1).

Correction Factor based on Temperature (Ground):

For the Correction Factor based on Temperature; While the cable installation is present in GROUND, the following table B.52.15 should be considered. This has a classification of correction factors based on the different insulations (PVC, XLPE) as well.

Kindly be noted that, the correction factor for the ambient air temperature of 20 *C can be considered as one (1).