In the continuing expansion of the utility construction segment of its diverse market interests, MDU Resources Group Inc., a Bismark, N.D.-based electric utility, has purchased two more electrical contractors.

With the purchases of Bell Electrical Contractors Inc., St. Louis, and Oregon Electric Construction, Portland, Ore., MDU will add $140 million in sales and increase its coverage of the Pacific Northwest and the Midwest.

Bell Electrical Contractors Inc., a 27-year-old electrical contracting firm with 50 nonbargaining employees, 200 union employees and annual revenues of approximately $40 million, focuses on commercial, industrial and institutional electrical work, as well as communications engineering, design and construction.

The acquisition of Oregon Electric Construction gives USI/MDU Resources another electrical contracting firm with expertise in power-line construction. The 50-year-old contractor specializes in new construction, repair, maintenance and service work for high-tech, industrial, health care, commercial, institutional and power generation customers. The company also provides preconstruction, design-build, design-assist and turnkey services for both electrical and integrated systems work. The company has 100 nonbargaining employees on staff and up to 600 union employees.

Ron Tipton, USI's president and chief executive officer says the acquisition will help the company expand in the Northwest.