The high-tension electrical cable supplied 150 kilowatts to the town southeast of Beirut, security sources said.
An army statement Friday said a second rocket was disabled before it could be fired.
The explosion, which shredded four other nearby cables, could be heard for miles and caused several power outages. The target of the rocket was not made clear, the Beirut Daily Star reported Friday.
2014: The Year in Music [PHOTOS]