Why must calculations for feeders consider ambient temperature?

The consideration of ambient temperature in feeder calculations is critical because it can significantly influence the resistance and ampacity of conductors. Ampacity refers to the maximum amount of electric current a conductor or device can carry before sustaining immediate or progressive deterioration.

As the ambient temperature increases, the resistance of conductors typically rises as well, which can lead to more heat generation during operation. This impacts the effective ampacity of the conductors, meaning they may not safely carry as much current at higher temperatures as they would at lower temperatures. Overlooking this factor can result in undersized conductors, potential overheating, and ultimately failure of the electrical system.

Understanding how ambient temperature relates to these characteristics ensures that electrical systems are designed with an adequate safety margin, promoting reliable and safe operation under varying environmental conditions.