covers must be installed to a minimum height of 2. Ventilated louvers also protect the cables and facilitate cooling by allowing natural convection (heat dissipation) to. This article explains the main requirements and good practices for cable tray systems, including tray types, materials, loading, supports, bonding, cable selection, and installation details. The content is written to be SEO-friendly and compatible with Yoast SEO for WordPress. Introduction and. The primary rulebook used in the safe use of cable trays is NEC Article 392. 305(a)(3), or comparable standards promulgated by States operating OSHA-approved State plans. They provide a secure pathway for wiring while simplifying maintenance and upgrades. Additionally, it addresses critical.