Cables installed in trays have lower ampacity than cables installed in free air or on cable ladder supports because the tray restricts airflow to the cables' bottom and top (if covered). However, they also present challenges in terms of heat dissipation, which directly impacts the ampacity of the installed cables. The use and installation of cable trays are covered by OSHA in 29 CFR 1910. Before installing cables, verify: This ensures the cable meets design and. Cable tray systems include ladders, troughs, channels, solid bottom trays, and other similar structures. ” Cable trays are not raceways, but they are treated as a structural component of a facility's electrical system.