Cable Types: Only use conductors rated for open-air environments, such as Tray Rated (Type TC) or Metal-Clad (Type MC) cables. There is no single global standard for cable tray systems. In practice, the applicable standard depends on three factors: In most international projects, product standards and installation standards are not the same: If you only follow one of them, the system may not pass approval. These systems, made from metal or plastic, are open structures designed to support electrical conductors, ensuring proper organization and safety. 305(a)(3), or comparable standards promulgated by States operating OSHA-approved State plans. In addition, this document contains several references to provisions of the National Electric Code. However, cable tray installation involves multiple regulations and technical standards.