This insulator on the poletop pin had been in service on a 25kV line in Rockaway Beach, OR. since the 1980's. It was located on a pole about 150 yards from the ocean. I talked to the linemen that had to change it out and they said they got a call that a "pole was burning" and found it arcing up through the pinhole....No Kiddin! It heated up the already severely corroded pole top pin and you are looking at the results. This was a heavily galvanized metal pin when installed new but as you can see, galvanized metal is fair game for the powerful salt air and fog. The ocean took it's toll.