An inside riser turns the tray into the wall — the cables run on the inside of the bend, the concave face. 10 (B) (1), the smallest size single conductor allowed to be installed in a cable tray is 1/0 AWG. Standard Aluminum Ladder • The rungs provide a convenient anchor for tying down cables in vertical runs or where the. At its heart, Cable Tray Design, Layout means choosing and setting up cable trays to hold and protect electrical and data cables. Cable trays give cables a clear path. We use different types of trays for different jobs: Ladder. Article Summary: A compliant cable tray installation requires a thorough understanding of NEC Article 392, proper structural support, and precise installation techniques.