Power was out for about an hour in eastern Idaho Falls on Friday afternoon.
More than 500 customers were affected, including the Grand Teton Mall and other businesses nearby.
Although the city had earlier estimated it might take up to eight hours to fix the problem, lights were back on in about an hour.
Idaho Falls Power Assistant General Manager Bear Prairie said the problem lay with a failed underground line from Sugar Mill substation to the distribution system. Another substation now handling the load.
The pole with the failed component is burned but OK. The point of failure is isolated and will be reviewed Monday.