Thousands of Derry homes suffered power cuts of varying duration as a result of the severe weather conditions that buffeted the North West during 'Storm Hector'.
Northern Ireland Electricity (NIE) is still working to restore power on some of the properties.
Over 2,000 homes were affected for a time in the Waterside.
Smaller scale outages in the Claudy and Drumsurn areas have yet to be resolved.
NIE said the faults were due to "severe weather conditions causing damage to the network".