The primary rulebook used in the safe use of cable trays is NEC Article 392. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed. Cable trays, commonly used in electrical installations, help organize and protect wiring systems. However, these trays are not immune to safety hazards that could cause system failures, fires, or other catastrophic events. 305(a)(3), or comparable standards promulgated by States operating OSHA-approved State plans. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent.