How to make a 90-degree flat bend in a cable tray

A 90° flat bend in a cable tray can be fabricated by marking, cutting, flattening, bending, and bolting a gusset piece to achieve precise measurements and structural integrity.

Step-by-

Step Fabrication Process

Mark the Tray Begin by marking the tray where the bend will occur. Identify the centerline and the area where the tray lips will be removed. The amount of lip to remove is typically 2/3 of the tray width, split evenly on either side of the centerline to allow proper bending (Construction step A).

Remove Tray Lips Use a hand grinder or file to carefully remove the tray lips along the marked area. Ensure protective equipment is used and avoid overcutting, which could weaken the tray (Construction steps B and C). Cut the Center Line Make a cut along the centerline of the tray at the bend location.

Take care to prevent the tray from opening or deforming during this step (Construction step D). Flatten the Tray Lip Use a blunt object to flatten the tray lip at the bend point. This ensures a smooth 90° bend without damaging the tray edges (Construction step E).

Bend the Tray Carefully bend the tray to a 90° angle. Use clamps or a bending jig if available to maintain accuracy. Once bent, bolt the two parts together to secure the bend (Construction step F).

Measure and Fabricate the Gusset Measure the distance between the two internal edges of the bent tray. Cut a gusset piece from a tray section to match this measurement, remove one lip completely, and bolt it to the 90° bend to reinforce the structure (Construction step G and H).

Measurement and Calculation Tips

Centerline Radius (CLR): For smooth cable transitions, measure the distance from the center of the bend arc to the midpoint of the tray width. This ensures compliance with bend-radius standards and prevents cable damage. Arc Length and Setback: Use trigonometric calculations or a cable tray bend calculator to determine the centerline arc length, chord, and setback distances for precise fabrication.

Gusset Sizing: The gusset should match the internal edge distance of the bend and be bolted securely to maintain structural integrity.

Assembly and Safety Considerations

Always use appropriate bolts and splice plates to secure the bend and gusset. Smooth-head bolts should face inward to avoid cable damage. Verify that the bend radius meets NEC, IEC, or NEMA standards for the cables being installed.

Ensure the tray is supported adequately along its length, especially near the bend, to prevent sagging or deformation. By following these steps and using precise measurements, you can fabricate a durable and accurate 90° flat bend in a cable tray suitable for electrical installations.