Depends on many factors. How is the conductor installed? How many current carrying conductors are installed with it? What are the temperature ratings of the terminals to which it is connected? Is the load continuous? What is the ambient temperature of the area around the conductor? Nothing in the electrical trade is an easy answer. The sooner you recognize that fact, the better off you will be.
What you ask is like asking, what color is the sky?
Answer: blue, except when it is grey, or orange, or yellow, or black, or any of the other colors that you can see in the sky under certain conditions. What are the conditions in which the conductor is installed? They will change your answer.