Occasionaly bears will shred wood transmission poles or a snake will climb the pole and crawl out on the conductor or beavers will flood the right-of-way or woodpeckers will make Swiss cheese out of your poles. But the vast majority of animal-caused outages on transmission systems are caused by birds. Almost always, large roosting or nesting birds.
The structures that seem to most often involved are steel transmission towers.Vultures and blue herons are the ones most often responsible. But other raptors will nest on transmission poles as well, especially ospreys.
The conductor clearances required by the National Electric Safety Code (NESC) are more than sufficient to prevent wingtip contacts. The outages caused by these birds are usually the result of contamination. Bird droppings on insulators will eventually cause tracking, arcing, and an outage.
By the time you get all the way through this web site, we will (hopefully) convince you that (with rare exceptions) you can't keep birds off your equipment, distribution or transmission or substations. Put perching guards on the poles and the birds may try to perch on the insulators, put perches on the poles and the birds will still try to perch on the crossarms. Try to count the number of perching sites on a transmission tower.
Utilities have tried everything they can think of to remove these birds, perching guards, pyrotechniques (Animal Damage Control Service of the United States Department of Agriculture), loud noises, "take" permits, etc. If utilities are going to successfully reduce outages, the focus has to be on protecting the equipment. Because the birds are not going to go away...
If you would like some help in designing and implementing a comprehensive program for getting your animal-caused outages under control, drop us a line. Don't forget to check the Bulletin Board. If you don't see anything there to help, leave a questionand we'll post it. Be sure to check the Product Catalog to see what commercial products are available.