An evidentiary hearing over a proposed multistate power line that would run through northern Virginia continued Wednesday in Richmond.

After about 40 hours of testimony between Dominion Virginia Power and its opponents over six days, the State Corporation Commission took a scheduled break on Tuesday. The hearing over the power line is expected to last at least two weeks.

The $1.3 billion Trans-Allegheny Interstate Line would be built by Dominion and Pennsylvania-based Allegheny Energy. The 500-kilovolt transmission line would run 240 miles from Washington County, Pennsylvania, to Loudoun County, Virginia.

Dominion says the power line is necessary to satisfy the growing demand for electricity in northern Virginia. They also say it would help avoid blackouts expected to start in 2011.

Opponents say the need is overstated and that the line would harm the environment.