The environment in which a cable is installed affects its ability to dissipate heat. You must adjust the current-carrying capacity (ampacity) using "correction factors" (
Electricity flowing through a cable behaves much like water flowing through a pipe. A larger pipe can carry more water with less resistance. Similarly, a larger electrical cable can carry more current with less resistance. how to calculate the cable size
Let’s put it all together.
Real-world conditions reduce a cable's ability to dissipate heat, meaning its capacity must be adjusted. The environment in which a cable is installed