The cable tray needs to be anchored at the support closest to the midpoint between the expansion joints with hold down clamps and secured by expansion guides at all other support locations. The expansion guides allow the cable tray to slide back and forth as it. Cable tray systems, essential for supporting electrical cables, are subject to thermal expansion and contraction due to temperature fluctuations. As cables and trays expand or contract, they can cause stress on the structure, leading to potential damage or misalignment. When installing Snap Track Expansion Guides, two guides should be used and attached to each side rail. Its robust construction and flexible design make it ideal for use in commercial, industrial, and residential settings. Figure 3-35 Cable Tray Installation Figure.