Wood Pole Inspection Extends Service Life

The wood poles commonly used to support overhead line conductors in Southern Brazil are produced from eucalyptus, an exotic tree species widely cultivated in the country. Unfortunately, wood is subject to deterioration, which can occur as a result of the action of physical, chemical and biological agents. In the electrical networks of Rio Grande do Sul, Brazil's southernmost region, more than 2 million wood poles are in service to support distribution and transmission lines. The common treatment for wood poles is a water-based chromated copper arsenate (CCA) preservative applied under pressure, as the use of pentachlorophenol and creosote are forbidden. In accordance with the CCA treatment, treated wood poles must have a lifetime of at least 15 years. Approximately 10,000 in-service poles were selected at random from a population of 760,000 poles, located in the AES Sul area. Among the 10,692 inspected poles distributed over five AES Sul regions, 90.7% were wood poles.