Why Don't You Bury those Lines?


Our member-systems often have customers ask why their system doesn't bury all of their electric lines so future ice storms and winds wouldn't be so damaging and cause so many outages. Here is an explanation from Keith Harvey, General Manager of North Central PPD in Creighton, NE.

For the most part underground lines may be less likely to have an outage but the time required to locate and repair the outage is much longer than with overhead lines (Cedar Pole News, Volume 22, Issue 2). According to the Edison Electric Institute (EEI), a study published in 2006 found that electric utilities in the State of Virginia in 2003 experienced overhead outages at 4 to 5 times the frequency of underground outages but that the average duration of the outage was 2.5 times as long with the underground lines. This same EEI report stated that the advantages of underground wiring diminish as the system ages. They discovered that an overhead system that was 40 years old had better reliability than a 20-year-old underground system. Finally, and of greatest importance is the fact that the cost of undergrounding lines may be up to 10 times as expensive as constructing overhead lines. The State of North Carolina studied the possibility of starting a state-wide program to replace all overhead lines with underground lines. They discovered that it would require a 122 percent rate increase and take 25 years to complete. North Carolina policy makers concluded that it was not economically feasible to move to underground wiring. And these are the reasons why North Central has not pursued undergrounding lines, except as absolutely necessary due to operational issues.