Cable tray systems are alternatives to wire ways and electrical conduit, which completely enclose cables. Cable trays are components of support systems for power and. Selecting a cable tray for high voltage power cables is a critical engineering decision that directly impacts system safety, thermal performance, and long-term reliability. ER cable is allowed to leave the cable tray for distances up to six feet, as long as it is supported and secured. It is available with a ventilated or solid bottom. For proper installation, design, and maintenance, adherence to international standards is essential.