Petersburg homes and businesses were without power for over an hour Wednesday.

The outage happened around 5:30 Wednesday evening. Petersburg Municipal Power and Light workers found that it was caused by a bad transformer located around 3-mile of Mitkof Highway. The transformer is 13 years old and feeds five homes in that area. Utility director Karl Hagerman writes that there’s no exact determination why it failed but suspects the age of the equipment and the warm weather contributed to the transformer failure.

Petersburg Municipal Power and Light is running backup diesel generators this week as annual maintenance work is done on the power lines connecting Petersburg to hydro-electric power plants on Mitkof Island and the mainland south of Wrangell. Hagerman thinks that the outage may not have happened if the community had been on hydro power. He writes that the backup diesels are more susceptible to being knocked off line when there’s a localized problem like this on the electrical grid.

Some parts of the local electrical grid had power restored in about 45 minutes. Other parts of town were without electricity for closer to an hour and a half.