Tokyo Electric Power Co. said Thursday it has completed repairs on damaged power cables that caused a major blackout in Tokyo and Chiba and Kanagawa prefectures for about three hours Monday morning.

With the completion of the repairs late Wednesday, Tepco's key electricity supply route linking its thermal power plant in Chiba Prefecture and Yokohama via central Tokyo has been restored, Japan's top power company said.

Tepco began repair work on the two power cables after they were hit Monday morning by a crane on a barge as it was being moved on the Old Edo River, which runs between Tokyo's Edo Ward and Urayasu, Chiba Prefecture.

The repairs were initially scheduled to be completed by Tuesday but were delayed due to such factors as bad weather, the company said.

The outage Monday left about 1.4 million households and offices without electricity and disrupted rail and road traffic.

The impact of the blackout on the metropolitan area was limited, however, as many people were away over the Bon summer holidays.

Tokyo Electric said the blackout was the second-largest in terms of the number of affected households and offices since it was established in 1951. The largest occurred in 1987 and affected about 2.8 million households and offices, it said.