If not designed and installed properly, wiring inside cable trays may pose hazards such as fire, electric shock, and arc-flash blast events. Cable trays can be part of a planned cable management system to support, route, protect, and provide a pathway for cable systems. Power, low voltage control. Working with cable trays is not just a routine installation job. 305(a)(3), or comparable standards promulgated by States. 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.