ST. PAUL — State regulators approved Xcel Energy Inc.’s request for another rate increase for Minnesota electrical customers Thursday.

The state Public Utilities Commission approved the Minneapolis-based utility’s request for a 4.6 percent interim rate hike increase in January, the sixth rate hike in eight years.

The action comes just a month after regulators finalized Xcel Energy’s 2013 rate hike, a 3.8 percent increase that was significantly less than what the company had sought.

The PUC unanimously approved the temporary rate hike, rejecting a request from the state attorney general’s office for no interim rate hike.

“We have back-to-back-to-back rate cases,” said Assistant Attorney General Ian Dobson, whose office represents consumer interests.

Before 2006, Xcel Energy’s customers in Minnesota went 12 years without seeing their rates go up.

By law, utilities have a right to charge interim rates while the utilities commission decides on permanent rates. If the final rates are less, Xcel Energy must refund the difference with interest.

For the average residential customer using 675 kilowatt-hours per month, the average monthly bill will go up $4, to $84.39 in January. The monthly boost in 2015 would be about $6.25 for the same customer under Xcel Energy’s proposed two-year rate plan.

Customers may be confused by upcoming bills. In December or January, customers also will get a credit to reflect Xcel’s smaller-than-requested 2013 increase.

The company says the increases will help pay for new wind investments and upgrades to Xcel Energy’s Monticello and Prairie Island nuclear plants, which supply 30 percent of Xcel Energy’s power.