32 Pa. Stat. § 625
None of the rights and powers conferred by this act shall be so used as to permit the utilization of any system of distribution, acquired, constructed, erected, used, or operated through the power of condemnation or appropriation conferred by this act, to supply, or commence to supply, within the limits of any city, borough, township, or district, in which, at the time of said commencement or proposed commencement, a company incorporated for the supply of light, heat, and power, or any of them, to the public by electricity is lawfully supplying light, heat, and power by electricity, without first securing a certificate of public convenience from the Public Service Commission of the Commonwealth of Pennsylvania authorizing such use within such limits. Nor shall this act be construed as impairing or limiting any right or power of eminent domain otherwise conferred by law.
32 P.S. § 625