Centered Cable Tray Reducer — Panel Lengths and Assembly

Choose the inlet, outlet and axial length

A centered reducer keeps the route centerline fixed while both tray sides move inward equally. Measure inlet base width, outlet base width and constant side height. Measure transition length along the route centerline between the two end planes.

Use a 400 mm inlet, 200 mm outlet, 50 mm side height and 500 mm axial transition length. The width reduction is 200 mm in total, giving 100 mm inward movement on each side. The outlet must be narrower than the inlet for this calculator.

Calculate the true length of each side panel

Let Δ = (inlet width − outlet width) / 2 and L be the axial length. The floor is a trapezoid with parallel end edges equal to the inlet and outlet widths. Its axial length is L. Each sloping floor edge and matching side panel has true length √(L² + Δ²).

For this example Δ = 100 mm, so each side panel is √(500² + 100²) = 509.90 mm long and 50 mm high. The floor area is (400 + 200) × 500 / 2 = 150000 mm². Adding both side panels gives an ideal total panel area of 200990.20 mm².

Worked example dimensions

Match the flat panel edges during assembly

The developed layout contains one floor trapezoid and two side panels. Identify the 400 mm inlet and 200 mm outlet before marking the floor. Mark both true-length side panels separately. Their lower joining edges follow the two sloping edges of the floor.

Move through Original, Mark, Cut and Form in the demonstration. The separated panels assemble around the matching edges while keeping their true lengths. If one tray edge must stay aligned, open the one-sided reducer. If the outlet grows wider, open the expander.

Review the fabrication detail

The panel development uses ideal zero-thickness geometry. Add the seam, fastening, material thickness and cutting allowances required by the chosen fabrication method. Check the inlet and outlet fits against the selected tray.