Cable tray systems are recognized as a wiring method by many national and international electrical codes. Typical requirements address: Tray construction, load ratings, and materials. Support spacing, mechanical strength, and. The primary rulebook used in the safe use of cable trays is NEC Article 392. To comply with code requirements and ensure system safety, metallic trays must be electrically continuous, properly bonded at all splice points, and securely connected to the building's grounding system. Here is the summary of the main points found in NEC Article. en completely installed, without damage either to conductors or structural system use maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray.