Aboveground Cable Derating Calculation

This tool will provide aboveground cable derating factor calculation. Derating factor is complied with IEC 60502 derating table from B10, B22 and B23. Cable insulation is thermosetting 90^oC. In case, project condition (for example, the air temperature is 42 degrees) differs with a predetermined value, the derating factor could be interpolated.

Also read: Underground Cable Derating Calculation.

INPUT:

Air Temperature (degree C):

20 25 30 35 40 45 50 55 60

Multicore or Single core:

Multicores Single core

Installation method:

On Perforated Tray – Horizontal – Touching On Perforated Tray – Horizontal – Spaced On Perforated Tray – Vertical – Touching On Perforated Tray – Vertical – Spaced On Ladder – Horizontal – Touching On Ladder – Horizontal – Spaced

Number of Cable Ladder/Tray

1 2 3

Number of Cables or Circuits in a Tray/Ladder

1 2 3 4 6 9

RESULT:

Derating factors	Reference Table	Result
Derating Due to Air Temperature (k1)	Table B10
Derating Due to Cable Arrangement (k2)	Table B22/B23
Overall Aboveground Derating (k1 x k2)

Cable derating factor has been discussed in Cable Derating Factors article. A short description here will explain the inputs required for aboveground cable derating calculation using IEC table. Finally, an overall derating will be generated to count for all 2 individual derating factors.

Derating due to Air Temperature (k1)

Select the air temperature from the dropdown list. Derating factor k1 will alter accordingly. In case, the air temperature is 30 degrees, the derating factor is unity (1).

Derating due to Cable Arrangement on Ladder/Tray (k2)

To facilitate selection of installation method, visual summary of installation methods is as below: