Thought this might be a good time to post this story... met an old lineman a while back, nearly 100 yrs. old. He had some amazing stories to tell... one was of some experimental suspension insulators. The linemen hated them he said, because they had a tendecy to puncture inside the cap but not drop the line. They had to check every pole site to find the bad one, and this was a remote line in the mountains through some very rugged country. Later when hunting this line, we did find some punctured caps just like he said! This line was dismantled in 1933, he remembered doing it.

For a photo showing what these looked like, [id=163746210].