In the Electrical workspace, click Manage tab Preferences panel Cable Tray. Article Summary: A compliant cable tray installation requires a thorough understanding of NEC Article 392, proper structural support, and precise installation techniques. This guide covers the critical steps, from selecting the right electrical cable tray and performing accurate cable fill. The primary rulebook used in the safe use of cable trays is NEC Article 392. Use this tool to estimate sloped section length, horizontal run requirement, cut marks, and installation feasibility. Measure this distance along the straight tray.