Conectiv, Inc. is a holding company formed in 1998 by the merger of Atlantic Electric Incorporated and Delmarva Power and Light Company, two large regional power utilities that supplied Southern New Jersey and the Delmarva Peninsula. The majority of the images in this collection come from the Delmarva Power and Light Company (DP&L), a predecessor of Conectiv, Inc. The images can generally be divided into three categories: DP&L equipment and facilities, DP&L employees, and views of buildings, both commercial and residential, throughout northern Delaware.

The Edison Electric Institute is the trade association of the electric utility industry. The minutes of the Institute's Transmission and Distributing Committee (1935, 1941-1970) include both business transactions of the committee and professional papers of representatives of member utility companies on a variety of subjects related to the transmission and distribution of electricty.

Pennsylvania Power & Light traces its origins to the various water and gas light companies that began operating in the eastern part of the state during the mid-nineteenth century. The records of the Pennsylvania Power & Light Company predecessor and subsidiary companies document the history of the gas and electric utility industry in eastern Pennsylvania in the years between 1853 and 1957. The collection includes both the administrative and operating records of more than 1100 companies that merged to form the PP&L system.

The Philadelphia Electric Company was incorporated under the laws of Pennsylvania on October 31, 1929, as a merger of The Philadelphia Electric Company (incorporated in Pa. on October 27, 1902), the Philadelphia Suburban-Counties Gas & Electric Company, and three other small utility companies. It is the primary gas and electric company for Philadelphia, its surrounding counties and Cecil and Harford Counties in northeastern Maryland. Their records consist of microfilm copies of the minute books of about 150 of the predecessor companies of the Philadelphia Electric Company.