NEC - De-rating Factor

The section displays calculated de-rating factor values, based on the cable installation configuration, after the Size Cable button is clicked.

The user can select a de-rating factor which will be used instead of the calculated value.

To select a de-rating factor, click the De-rating Factors button. The Derating Factors window is then displayed:

Select the required factor from the list. The list includes the de-rating factors that are part of the standard and user-defined project specific de-rating factor set up using the Cable Sizing Configuration window.

If a value is 1 then the rating will have no effect on the calculation.

Click Save. The selected factor is then displayed in the Chosen De-rating Factor field.

The Chosen De-rating Factor field value can only be set by the user to be equal to or less than the Calculated De-rating Factor field value.

If this field is blank when the Size Cable button is clicked, it will be automatically populated with the calculated value.