The diagram shows a simplified version of a large area outage. Our linemen start from the substation transformer out onto the main feeder lines. It would be useless to repair a pole if the main lines were not energized. Once there is power at the substation, the three-phase feeder lines are repaired and energized. The next lines to be repaired are the tap lines off the three-phase lines. The last to be repaired and energized are the single service outages. Generally, the lines that will get the most services energized in an area are repaired first.
In the diagram, fault "A" would be first (three-phase feeder line). Fault "B" would be next (a tap line), while single service outages "C" and "D" would be the last to be repaired.