The Continued Use of Wood in Modern Utility Line Transmission
For more than a century, wooden utility poles have dotted the landscape of North America, carrying both electricity and communications cables across the continent. Though steel and concrete have emerged as rivals, treated wood poles remain a popular choice for electric and phone companies.
According to the Western Red Cedar Association, roughly 100 million wood utility poles remain in existence today. Modern treatment, growing and harvesting techniques have kept the market for wood poles strong.
Modern Treatment Methods
The popular way to treat utlity poles in the past decade has been the use of Chromated Copper Arsenate or CCA. This is the method for treating outdoor lumber for decks, sheds and other structures exposed to the elements.
In CCA treatment, poles are first exposed to a vacuum, allowing wood fibers to open. They are then placed under high pressure while the CCA solution is injected into the wood. The Copper in the solution acts as an antifungal and water resistant preservative. The Arsenate is used to deter insects. Chromate is used as a binder for the preservatives and the wood fibers.
In addition to CCA treatment, some quality manufacturers apply an additional emulsified mineral oil solution. The mineral oil saturation is an additional moisture barrier. More importantly, it acts to soften the wood, making pole climbing an easier and safer task.
Besides longevity other benefits of wood poles include:
• Insulating properties – as a natural electrical insulator, wood poles do not need earthing for safe installation;
• Wind Resistance -trees from which poles are made are naturally flexible and able to withstand high winds;
• Weight – wooden poles weigh far less than concrete poles. In addition, poles can be stacked numerous layers upon each other without the risk of crushing or deforming their shape. More wooden poles can be transported to the job site per truck than steel or concrete poles;
• Ecological – as a naturally renewable material, modern companies purchase pole trees from managed growth suppliers. Normally, several tree saplings are planted for each harvested tree. Techniques for cutting, debarking and shaping of trees into poles can often be done with a single machine.
Though newer technology may eventually replace wooden utlity poles, they remain an ecologically and cost effective method for transmission of electric and communication lines. The latest wood preservation technology has kept them a popular choice for the foreseeable future.