The fabrication coefficient for cable tray corners is a multiplier used to calculate the required tray length for bends, typically based on the bend angle and offset distance.

Understanding Fabrication Coefficient

In cable tray installation, a fabrication coefficient (or bend multiplier) is applied to determine the straight tray length needed to form a corner or offset. This ensures that the tray pieces fit precisely when bent at a specific angle, avoiding gaps or excessive material. The coefficient accounts for the geometry of the bend and the tray width.

Typical Values

• For standard 30° bends, a common multiplier is 2.0.
• For 45° bends, the multiplier is often 1.4–1.5.
• For 90° bends, the multiplier is typically 1.0, meaning the offset distance equals the straight tray length required between bends. These multipliers are used in horizontal, vertical, or compound offsets to calculate the sloped section length and mark cut points on the tray for fabrication and installation .

How to Apply

1. Measure the offset distance between the start and end points of the corner.
2. Multiply the offset distance by the fabrication coefficient corresponding to the bend angle.
3. Mark the straight tray section using the calculated length to ensure proper bending.
4. Install the tray following the calculated dimensions to maintain continuous cable flow and structural integrity .

Additional Considerations

• Always verify the minimum bend radius for the cables to prevent damage during installation .
• Material type (aluminum, steel, or fiberglass) may slightly affect the coefficient due to flexibility and bending characteristics .
• For complex or compound bends, use cable tray offset calculators or manufacturer-provided tables to ensure accuracy . By applying the correct fabrication coefficient, installers can reduce material waste, maintain proper cable support, and ensure compliance with electrical standards.