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Lightning Arrestors

For all those who have never had an incident with an arrestor, go to the past accidents in the "near misses" forum of Powerlineman. There is probably only a small percentage of the incidents regarding arrestors reported in this forum. There must be many more. In 25 years of line work, I have 2 bad experiences with arrestors. One was installing a used 3kv arrestor that was faulty. It was installed on the load side of a transformer switch. When I closed in the can, the top of the glass blew off the old carbon and gap type arrestor and landed about 100 feet away. I think it was upside down in the weather and was full of water. The second involved arrestors installed on a new underground dip. This one involved a 3kv arrestor mistakenly installed on 8KV dip. It was one of those arrestors where the 3kv and 9Kv are virtually the same to look at. The arrestor was hooked up on the line side of the fused switch. It is our policy that no arrestor is to be hooked up by hand and you have to have a hold off to perform all fine work except closing or opening switches. I was using a 4 foot shotgun to tap onto the line. Just the same, even using a 4 foot shot with a hold off, there was still a loud explosion and flash. The hold off took out the feeder and probably prevented sever damage to me (who was in the flash are) buy reducing the number of cycles the fault current lasted. I was luck I used a stick, hold off and glasses. I did not have hearing protection.