What do all the wires and boxes that hang on a utility pole do?

Utility poles really live up to their name. They're used for electric power as well as communications services such as cable TV and landline phones. In the future, they will support even more services, such as electric vehicle charging and wireless internet transmission.

Poles often top 40 feet in height, weigh over one ton and are set at least six feet into the ground. Here is a description of some of the items hanging on utility poles today.

• Static wire is a grounded top wire that protects other conductor wires from surges due to lightning strikes.
• Primary distribution lines are three bare conductors that carry up to 34,000 volts from substations (typically 7,200 volts).
• Porcelain insulators restrict the transfer of electricity between wires and the pole.
• Step-down distribution transformers reduce voltage from primary conductors to secondary conductors. This means they are stepping down the voltage from 7,200 volts from the primary conductor (power line) to 240/120 volts to run to your home.
• Secondary lines are three bare conductors between poles and insulated conductors to homes (2 conductors plus one ground wire). Secondary lines are the lines that run to your meter base.
• Lightning arrestor diverts voltage spikes from lightning to ground.
• Disconnect switch is a hinged switch and fuse that electrically isolates downstream circuits.
• Pole top capacitor banks offer the localized benefits of voltage support and power factor correction.
• Cable TV wires are the lowest-level wires with black or gray boxes that amplify the signal.
• Telephone/fiber wires are the lowest-level wires with black box splitter/breakout/tap for service feeds.