Abstract: A cable tray that can be easily assembled at a construction location and which provides a configuration that can be modified to adapt to various on-site requirements. A preferred configuration of the cable tray disclosed herein includes a commercially standard strut suspended from an overhead surface and having a U-shaped rung fastened to the strut. The system provides a fastening system that can be installed using conventional, readily available, high-speed driver systems. The cable tray of the present invention may be mounted so as to depend from horizontal surfaces or may be directly bolted to a vertical surface. Further, the cable tray may be adapted to provided a two-tier cable tray even after installation of the primary cable tray. Various fastening systems are disclosed which attach the rung to the strut.