The maximum voltage across a potentiometer is normally limited by the power rating of the potentiometer, which should be quoted. A 1.0k, 1/2W unit would be limited to 22 V, preferably derated to less than 15 V for a 2:1 power safety factor.
Where things get tricky is if you are using it as a variable resistor, where the power for a given voltage varies with the change in resistance.
By definition, a potentiometer is used as a voltage divider, but there may be current passing through the wiper.