Cable tray systems are recognized as a wiring method by many national and international electrical codes. Typical requirements address: Tray construction, load ratings, and materials. 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. Here's what you need to know: Cable Types: Only use. Cable tray may be used as the Equipment Grounding Conductor (EGC) in any installation where qualified persons will service the installed cable tray system. Our focus has always been on solutions from the field of cable support systems.