This appendix provides the design criteria for seismic Category I cable trays and their supports. 1 Codes and Standards The design of cable trays and their supports conform to. THIS REPORT WAS PREPARED BY THE ORGANIZATION(S) NAMED BELOW AS AN ACCOUNT OF WORK SPONSORED OR COSPONSORED BY THE ELECTRIC POWER RESEARCH INSTITUTE, INC. NEITHER EPRI, ANY MEMBER OF EPRI, ANY COSPONSOR, THE ORGANIZATION(S) NAMED BELOW, NOR ANY PERSON ACTING ON BEHALF OF ANY OF THEM: (A). In regions prone to seismic activity, ensuring that your cable tray system is capable of withstanding such events is vital. This article will explore the importance of seismic resistance in cable trays, discuss when seismic braces are necessary, and help you understand how to make informed. This checklist focuses on the engineering decisions that matter most when specifying cable trays for high-seismicity projects. INTRODUCTION large telecommunication company embarked on a program that included building a series of telecommunications facilities in the Seattle, Washington area.