Support spacing is one of the most important parts of cable tray design. A tray can have the correct width and finish but still perform poorly if the span, cable weight and fittings are not reviewed together.
Start with the installed cable load
List the cable types, approximate weight, grouping and expected additions. Consider whether the route carries power, control, instrumentation or communication cables. The design load should reflect the approved project schedule rather than only the first shipment.
Coordinate span with the manufacturer's data
Support spacing should follow the tray manufacturer's load tables and the approved structural design. Longer spans generally require a stronger tray profile, thicker material or a different support arrangement. Do not copy a spacing value from another project without checking tray width, material and load.
Review bends, tees and changes in elevation
Fittings change how a route transfers load. Add supports near bends, tees, reducers, drops and expansion connections where required by the design. Keep supports aligned and level so joints are not forced out of position during installation.
Leave room for future work
A small amount of spare capacity can make future cable additions safer and less disruptive. Confirm the required fill, clearance and separation rules with the responsible electrical designer and local code.