Seismic design recommendations for substations, including qualification of different equipment types are discussed in this amendment. Design recommendations consist of seismic criteria, qualification methods and levels, structural capacities, performance requirements for equipment operation, installation methods, and documentation. Additional files can be found here: https://standards.ieee.org/wp-content/uploads/2025/01/693a-2024_downloads.zip

The amendment alters recommendations for the seismic design and qualification of transformers and select appendages attached to transformers and surge arresters. The amendment alters recommendations for response spectra, time histories, and qualification methodologies associated with them.

This recommended practice is for new substations and planned additions or improvements to existing substations. It is not intended that existing substations must be retrofitted to these recommended practices. Instructions on how to include this recommended practice in specifications are provided. IEEE Std 693™ is designed as an integrated set of requirements for the seismic qualification of electrical power equipment. Users should use IEEE Std 693 without modification or removal of any requirement, except as allowed herein.