Perhaps you are correct, but if you read through 310.13 and the notes the wording and language indicates that operating temp. is intended as ambient temp. Also, I learned in trade school that the temp rating indicated max ambient temp. for that particular insulation. Thats probably my source of confusion. The code should, in the futer, clerify this. Perhaps a call to a wire MFG. will shed some more light on the subject, as I am still not shure what the intent of maximum operating temp. Read it carfully it could go either way.
