Hundreds of homes in Lancing have been affected by power cuts.
The outage initially affected 4,162 properties in the south of the village but 344 homes were still without power at 04:15 GMT, said UK Power Networks.
The operator said engineers were working on an underground cabling fault which was first reported at 03:20.
Specialist engineers were also working remotely to divert electricity to households and aimed to restore supply by 08:00, the company said.