What length of bracket should be selected for various bends in cable trays

Brackets should be positioned close to bends, intersections, and terminations—typically within 250 mm—to ensure proper support and prevent cable strain.Bracket Placement at BendsFor horizontal or vertical bends in cable trays, brackets must be installed as close as 250 mm from the bend to provide mechanical support and maintain the tray's structural integrity . This ensures that the cables do not experience undue stress at the point of directional change. At intersections, T-pieces, or terminations, the same 250 mm guideline applies to prevent sagging or misalignment.Support Spacing for Straight RunsFor straight sections of cable trays, brackets are generally installed at intervals of up to 1200 mm, depending on the manufacturer's recommendations and the tray type . The exact spacing may vary based on the tray material, width, cable weight, and environmental conditions. For flexible systems, such as J-hanger installations, the distance between supports should be calculated to achieve a 2% deflection or offset, which may require closer spacing for stiffer cables like MDPE sheathed types .Vertical Runs and Strain ReliefLong vertical runs require additional considerations. For vertical sections exceeding 32 meters, strain relief sections should be incorporated, typically by offsetting the cable by at least 2 cable diameters per strain relief section . For extremely long vertical runs (over 100 meters), additional tension-relieving measures are necessary to prevent excessive mechanical stress.Practical RecommendationsAlways use fire-resistant brackets for all cable types to ensure compliance and safety .Position tray joints and bends as close to supports as possible to maintain stability .For fabricated or non-standard bends, ensure that cut edges are smooth and coated to prevent corrosion or damage to cables .Follow manufacturer-specific guidelines for bracket length and spacing, as these may vary depending on tray type, material, and load capacity . By following these guidelines, cable trays will maintain proper alignment, prevent cable strain, and comply with installation standards.