Above and below

According to Pieper, there are three main components of power lines. The first are the lower-voltage lines serving individual homes or businesses or residential neighborhoods. They include secondary lines connected to homes that carry between 120 and 480 volts, as well as distribution lines inside newer neighborhoods that typically carry between 12,000 and 34,000 volts. For aesthetic reasons, burying power lines has become the norm in residential neighborhoods built in the last three decades or so, said Pieper, with the developers passing on the cost to home buyers.

There are also distribution lines transmitting electricity from substations to neighborhoods along main roads. High-voltage transmission lines carry 69,000 to 765,000 volts of electricity over long distances, such as from distant power-generation plants to substations in towns.

Underground distribution and transmission lines are mainstream in Europe. But the vast majority in the U.S. remain aboveground: aluminum-wrapped steel cables strung along wood or concrete poles in the case of distribution lines or large towers in the case of transmission lines, according to Carl Potter, a Tulsa, Okla.-based utility safety consultant.

High-voltage power lines are only found underground in the U.S. in dense commercial areas such as major metropolitan downtowns, where aboveground lines interfere with traffic and real estate.