Hello. I just received a wall oven with a whip line that is made of 1/2" non-metallic sheathing with 4 separate conductors. The conductors appear to be no larger than 10 gauge and occupy less than half of the sheathing volume. I would like to route the line up and behind the oven within the cabinet, but the sheathing is a bit too thick. I have 8 gauge romex (correct number of conductors & NM-B) that would fit perfectly but wonder if there are temperature issues or other reasons to reject the idea. Thanks!