After broad outages turned out the lights on as many as 10,000 Rocky Mountain Power customers Thursday, most of the electricity had been restored early Friday.

At 9 a.m., about 400 customers were still without power in the Salt Lake Valley and the Fountain Green area, southeast of Nephi in Sanpete County.

The Salt Lake outages were expected to continue Friday as crews prepared to locate and repair bad underground cables in West Valley City near Decker Lake. That problem has been contributing to outages since Thursday afternoon, but crews hoped to have it fixed before the end of Friday, said Rocky Mountain Power spokesman David Eskelsen.

The outage count around Utah reached 10,000 on Christmas morning between 9 and 10 a.m. Eskelsen said that was due to a voltage-control problem at an Oquirrh power substation in West Jordan.

The power outages varied between 4,000 and 6,000 through Christmas Day with many occurring in the Salt Lake area, Eskelsen said.

A problem with a transmission line in Tremonton also cut power to 1,400 customers on Thursday.