As an extension of my previous inquiry into air-core chokes, I'm trying to determine the voltage insulation rating of magnet wire, without much luck. Few of the audio air-core choke manufacturers list that data, and none of the magnet wire manufacturers I've checked give it either. For example, this company lists the type of insulation used, and its thermal properties, but nothing about its voltage withstand ratings. This appears to be common practice. I see references to insulation grades (1, 2, or 3), which seem to be how many insulation layers are present on the wire, but I still haven't found any voltage rating for those grades.
How can I be sure that the insulation on magnet wire will not break down under a given voltage? Am I not looking in the right place for this rating? Am I looking at the wrong kind of magnet wire for high-voltage applications? Are we required to build chokes such that consecutive windings of magnet wire are close enough in voltage that the insulation rating of the wire doesn't matter?