Prepared by the Electric Power and Communications Committee of the Technical Council on Lifeline Earthquake Engineering of ASCE. Recent moderate and strong California earthquakes demonstrate that parts of electric power systems are very vulnerable to damage. Most damage is due to the failure of porcelain elements in high-voltage substation equipment, although performance is also strongly influenced by specific equipment designs and installation practices. Damage to various lifelines and structures has impaired the performance of some communication and control systems after earthquakes. This Manual issues methods to improve the earthquake response of electric power systems. It deals with major power system elements—power generating stations, transmission and distribution lines, substations, system communications and control, and ancillary facilities and functions. A large portion of the document is devoted to high-voltage substations, as this is where most power system damage has been concentrated. Topics include: sources and effects of earthquakes; overview of earthquake performance of power systems and facilities; approach to improved earthquake performance; substations; transmission and distribution lines and support structures; power generating facilities; system control; communication systems; and ancillary facilities and functions.