Wooden Poles

Utility poles are commonly utilized to hold two sorts of electric power lines : distribution lines and subtransmission lines. Distribution wires carry electric power from local power sub-stations to customers. Often they carry voltages from 4.6 to thirty three kilovolts ( kV ) for at least thirty miles, and include step-down transformers to step the voltage down from the 1st voltage of the lines to the lower secondary voltage made use of by the destination consumer. A service drop carries this lower voltage to the customer's grounds. Subtransmission lines carry higher voltage power from regional substations to a local substation. They usually carry 46 kV, 69 kV, or 115 kV for distances up to 60 miles. Voltages of 230kV can be put on two- or three-pole towers. Transmission lines carrying voltages of above 230kV are typically not supported by poles, but by metal pylons ( known as transmission towers in the U. S. ).

For business or other sound reasons, for example to economize on space in built up areas, a distribution line is ordinarily carried on the same poles as a subtransmission line but mounted under the higher voltage lines ; a practice called "underbuild". Telecommunication wires could be supported by the same wooden poles that support the power lines ; poles so arranged are known as joint poles. They'd also have their own dedicated poles.