Title 66 of the Public Utility Code is available online at Unofficial Purdon's Pennsylvania Statutes from West.
Scroll down to Title 66 Pa. C.S.A. Public Utilities, and select that link. Title 66 is also available through the Pennsylvania General Assembly website.
Public utilities are regulated under Title 52 (Public Utilities) of the Pennsylvania Code, available online at www.pacode.com.
Any proposed regulation or changes to existing regulations must go through a lengthy review process. They are printed in the Pennsylvania Bulletin for public comment and are reviewed by the Independent Regulatory Review Commission House Consumer Affairs Committee, Senate Consumer Protection and Professional Licensure Committee, Attorney Generals Office, and Governors Budget Office.