Indoor: Consider ceiling height and space to ensure sufficient access for maintenance personnel. Use appropriate cable ties or clamps to prevent damage caused by vibration or. As a key support system for cable laying in building electrical engineering, the installation quality of vertical cable trays directly affects the safe operation of power, communication, and other circuits. Proper installation is not just about placing the. association representing the major electrical equipment manufac-turers in the U. The Cable Tray 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. NEC Article 392 outlines the key rules for installing and maintaining industrial cable tray systems. This article. According to the 2005 National Electrical Code® (NEC), a cable tray system is “ unit or assembly of units or sections and associated fittings forming a structural system used to securely fasten or support cables and raceways. ” Cable trays support cable across open spans in the same manner that.