Up to 3,000 homes and businesses in Derry were left without electricity yesterday afternoon.
The power shortage occurred just after midday, with NIE emergency repair teams responding to the problem immediately.
It is understood that the power-cut affected the Steelstown, Shantallow and Gransha areas of the city, and engineers attended on site and worked to restore electricity supplies as quickly as possible.
A number of local schools, left without power and heating, were subsequently forced to send pupils home for the rest of the day.
The power cut lasted two hours before being restored at 2.02 pm.
A spokesperson for NIE, the electricity network company, confirmed the cause of the power-cut.
“Damage to an underground electricity cable by a third party caused the problem,” the spokesperson said.
“Emergency repair teams from NIE, the electricity network company, responded immediately to isolate the damaged cable and restore power to customers via alternative network circuits.”