Northern Ireland Electricity has confirmed that an outage this morning affected over 3,000 homes and businesses in the Derry area.
Work is set to continue over the coming days to ensure a permanent fix to the fault.
The fault in an underline cable resulted in outages across various areas of Culmore, Galliagh and other areas this morning.
Traffic lights at Culmore and other areas were also affected.
A spokesperson for NIE Networks said:
“A fault in an underground cable affected around 3,200 homes and businesses in the early hours of Wednesday morning.
“NIE Networks emergency teams responded immediately and restored the majority of customers by 06.11am. “Engineers continued to work to restore power to the remaining 148 customers in the Cashel Hill Park area by 12.20pm.
“Customers in the surrounding area would have experienced some flickering supplies as work was taking place.”
She added: “Permanent repairs to the cable will be ongoing over the coming days.”