Expansion connectors shall be provided at building expansion joints and in long runs of outdoor tray at intervals of 30 m (100 ft) or per NEMA VE 2.Cable trays shall be fastened to the support system using guides that allow for longitudinal movement. Cable tray installations shall be installed so connectors are not located in center points of span between supports or directly on supports. Cable tray supports shall be located so that connectors between horizontal straight sections of tray fall between the support point and the quarter-point of the span.Cable tray elbows shall be supported per NEMA VE 2 requirements.Cable trays shall be installed according to the latest revision of the NEC, NEMA VE 2, and manufacturer’s installation instructions.Cable Tray Installation Guidelines for Engineers