When cable trays contain conductors rated over 600 volts they are required to be marked “DANGER — HIGH VOLTAGE — KEEP AWAY” at no further than 10-foot intervals. What has changed is the way those labels are required to look in order to adequately warn of the. Understanding cable tray spacing is key to meeting safety regulations and maintaining system performance. The spacing between trays, whether horizontal or vertical, depends on various factors like cable type, environment, and tray material. Code Change Summary: New marking requirements were added for cable trays. When cable trays contain conductors rated over 600 volts they are required to. ng standards, performance standards, test standards and application in this document have been tested extens ompetent professional en completely installed, without damage either to conductors or structural system use maintain spacing or to keep cables in place when the tray is ect the minimum. Is your cable tray system optimized for safety, dependability, space and cost savings? Cable tray (or cable ladder) systems are a popular alternative to electrical conduit systems, as they have an outstanding record for dependable service, design flexibility and cost savings in commercial and. NEC Article 392 outlines the key rules for installing and maintaining industrial cable tray systems.