The DC resistance of a conductor or cable is that defined by ohms law. It is a function of many factors including temperature which greatly affects the resistance of a given material. Copper and Aluminium are the most widely used conductors. Their resistance (DC) increases with increasing temperature.
The copper wire resistance in the above table are at 20 degree Celsius. To get the resistance at any other temperature above this, we use the equation:
Actual values of α depends on the composition of the material in addition to temperature. For copper and aluminium, taking, α = 0.0039 will give reasonable accuracy for most conductor calculations