The path of power to your home is guarded by silent sentinels—utility poles—that are under constant attack by Mother Nature and, sometimes, by people.
Electric cooperatives own and maintain 2.5 million miles of line stretching across three-quarters of the United States. Some lines are buried, but more than 2 million miles of lines are aboveground. Since there are generally 18 wood poles for every mile of distribution line, electric co-ops rely on more than 37 million poles to deliver power to your home.
Utility poles can take several forms: concrete, steel, ductile iron, composite fiberglass, and—overwhelmingly—wood. Why do utilities prefer treated timber?
Tried-and-true wood poles are more affordable and work well in most situations. Steel and composite fiberglass poles often cost at least twice as much, although these alternatives claim a longer lifespan (most have not been in service long enough to verify the claims). Alternatives are used where wood isn’t the best choice, for example, where woodpeckers are a problem.
Wood poles—pressure-treated with preservatives to extend their lives—stand the test of time. A wood pole’s lifespan generally ranges from 30 to 50 years, and in the right conditions, it can last even longer.
Wood poles battle a wide array of adversaries: acidic soil in the Midwest, heavy moisture in the South, and woodpeckers in the Mid-Atlantic. Utilities generally inspect poles on a 10- to 12-year cycle to identify problems.
People shorten a pole’s lifespan, too. The National American Wood Council estimates 5 percent of poles replaced annually were broken by car accidents.
Attaching signs, basketball hoops, clothes lines, birdhouses, satellite dishes, or other items to wood poles with staples or nails can also shorten a pole’s lifespan. Not only do these items create safety hazards when workers need to climb a pole, the small holes speed up a pole’s decay.
—NRECA COOPERATIVE RESEARCH NETWORK