A power cut briefly hit the Danish Baltic Sea island of Bornholm on Monday.
Authorities initially said an underwater cable from Sweden that provides electricity had been severed, but later blamed it on a local fault.
Energinet, a public company that owns the sea cable which provides electricity to Bornholm, said the power had been restored for all of the nearly 40,000 residents of Bornholm within four hours.
The power outage occurred just before 8am local time, Trefor, which provides Bornholm with power, said. Bornholm is a rocky island of 227 square miles (588 sq km), south of Sweden.
The outage provoked concern after blasts last month damaged two Russian-built natural gas pipelines in the Baltic Sea — two leaks were reported off Sweden and two off Denmark. All were in international waters.
The governments of Denmark and Sweden said they suspected that several hundred pounds of explosives were involved in carrying out a deliberate act of sabotage. The leaks from the Nord Stream 1 and 2 pipelines discharged huge amounts of methane into the air.