SALEM, Ore. — Officials from an Oregon electrical utility company say indoor growing operations for legal marijuana businesses are causing problems for the state’s electrical grid.

The Statesman Journal that Pacific Power reported Wednesday that grow operations have taken grids above capacity, blowing out seven transformers since July, causing outages and equipment damage.

A spokesman for Portland General Electric says his company has had similar problems, with anecdotal reports showing about 10 percent of their transformer blowouts are from growing operations. He says there are about 400 blowouts each year.

To curb the problem, utility companies are asking marijuana growers to talk to power providers before starting home or commercial operations to make sure electrical systems are operating correctly.