Suppose we direct-buried some 8 AWG cable. It's now under a parking lot, and retrenching it is out of the question. Now, needs have changed and we need to get 50A out of the circuit, which is possible with 8 AWG in the 75C column. The wire is good for it.
What else is needed to qualify to use the 75C column?
Does anything change if this is wired in the interior of a house?