Yes, repairing a fault in an underground cable is significantly more difficult and time-consuming than repairing an overhead line. A fault in an overhead line is usually visible and can be located and repaired in a matter of hours or days. For an underground cable, the exact location of the fault must first be identified using specialized equipment, a process that can take a long time. The repair then requires extensive excavation, and the process from detection to repair can take days or even weeks.