When I did a little modification of my incoming water line, I noticed that the copper line was really starting to get deteriorated for being too warm. The heat tape was wrapped without any space between the wraps. I replaced the copper and heat tape but this time with a shorter one that just runs parallel to the pipe that was suggested by the installation instructions. I should have know this since when I was working at a chemical plant, we would make heat tape runs of hundreds of feet parallel to the lines.
In short, too much heat can be bad.