American Transmission Co (ATC) said it will begin rebuilding the 18-mile, 69,000-volt Brodhead-South Monroe electric transmission line in the US.

The construction activities on the approximately $11m project are expected to begin next month and the power line is projected to begin operation in December 2011.

The project received approval from the Public Service Commission of Wisconsin in April last year, and the work will involve installing new poles, wires and insulators.

The rebuilt line will follow the existing route and the new line design will allow for longer span lengths and fewer poles, ATC said.

According to the company, the age and condition of the existing line, which was built in 1950, necessitated the rebuild.

ATC owns, operates, builds and maintains a high-voltage electric transmission system serving portions of the US states of Wisconsin, Michigan, Minnesota and Illinois.