To summarize this example:

To avoid overheating the conductor in this case, based on standard conditions of use – that is, with no correction or adjustment factors applied – a 3 AWG conductor from the 75° column would be acceptable. But when the additional 25% is added for the continuous load at the overcurrent device, that requires a 1 AWG from the 75° column. The minimum size overcurrent device will be more than 100 amps (125 amps), so on the supply end of the conductor there would be a 75° terminal, but on the load end a 60° terminal would be assumed. The size required for termination temperature provisions is 2 AWG.

This example produces three different minimum sizes, and the largest minimum size is 1 AWG based on the continuous load and the overcurrent device. Other examples could produce a largest minimum size based on the conditions of use or the terminal temperature requirements, so all three issues must be considered in every case.

NOTE: This is an unformatted excerpt from our online fire protection training library.