Due to their exposure to the open air because of the cable trays, the wires contained within need a very durable outer covering. The regulations dictate that the cables must either be Type TC (also known as Tray Rated) or must be metal-armored (Type MC). 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. NEC Article 392 covers the requirements for cable tray systems, including the types of trays recognized, which wiring methods can be installed. NEC Article 392 explains cable trays, their components, appropriate wiring methods for cable trays, and instances where they are and are not permitted for use. It's a support system for cables and raceways.
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