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 decisions for your installation. Eaton's TOLCO seismic bracing solutions help protect people and non-structural components during an earthquake. During an earthquake, cable trays are exposed not only to gravity loads and normal service loads, but also to lateral movement, vertical acceleration, vibration, and building drift. Cable tray runs in seismic zones need more than normal hanger spacing. A coordinated seismic bracing system uses strut channels. High-seismicity projects place much greater demands on cable tray systems than ordinary installations.