This chapter discusses the seismic design standards and practices employed in high seismic hazard areas of North America. It provides general guidance to substation designers on seismic design concepts and the application of Institute of Electrical and Electronic Engineers 693 for equipment qualification. High-voltage equipment was often damaged due to the use of massive and brittle porcelain components and the absence of recognized seismic design standards and technical guidance. Electrical substation equipment are complex machines whose primary functions require characteristics that are often at odds with those of a robust seismic design. Substation seismic design standards generally specify the seismic demand, methods for performing the engineering evaluation of the equipment, and the acceptance criteria. The seismic qualification of equipment should be performed with the same support structure that is to be used in the field installation. The design of flexible bus work utilizes the terminal displacements computed or measured in the seismic qualification of the stand-alone equipment.