A fault in an underground cable is what is thought to have left more than 2,000 properties in St Helier without electricity.
The outage began at around 7.45pm on Tuesday (17 October) and was fully restored shortly before 10pm.
Jersey Electricity says a safety protection device was triggered in the Mont Millais and Colomberie area.
Boss Chris Ambler has apologised for the unexpected interruption.
"Our rapid response teams worked diligently to ensure power was restored as quickly and safely as possible.
We understand the significant inconvenience caused by power interruptions and sincerely apologise to all those affected. We are immensely grateful for the patience and understanding shown by our customers during last night's unexpected incident."
It was a blow for some homes and business who were also affected by an island-wide gas outage that began on Saturday 7 October.
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