About 770 people in the New Road area of Ridgewood, Uckfield, were affected by a power cut on Friday night and some are still being supplied electricity via a temporary generator.
A spokesman for EDF Energy Networks said an unusual combination of a fault on an underground cable and another on overhead lines interrupted supply at about 6.30pm on Friday.
Engineers worked on the faults throughout the evening and into the night with the first 255 customers having power again within 20 minutes and all supplies restored, in groups, by 2.21am on Saturday.
About 280 people have electricity via a temporary generator which will be in place while further repairs are undertaken. After that they will be restored to the permanent network.
The EDF spokesman said: “We appreciate how difficult it can be to lose power, especially at the start of a weekend and would like to apologise for the inconvenience caused by this incident.”