How to use a cable tray oblique tee

Oblique tees in cable tray systems should be positioned to maintain proper cable routing, support, and bend radius while ensuring structural stability and compliance with design standards.

Purpose of Oblique Tees

Oblique tees are used to branch cables at an angle from a main cable tray run, allowing for smooth transitions to equipment or secondary tray runs without sharp bends. They are particularly useful in instrumentation, control, and power cabling where maintaining cable integrity and minimizing stress is critical .

Positioning Guidelines

1. Alignment with Main Tray: The tee should be installed so that the branch tray aligns with the intended cable path, avoiding unnecessary twists or sharp angles. The angle of the oblique tee typically ranges between 30° and 60°, depending on the layout and space constraints .
2. Support and Load Considerations: Ensure that both the main and branch trays are adequately supported near the tee. Supports should be placed close to the tee junction to prevent sagging and maintain load capacity, especially for heavy-duty trays .
3. Bend Radius Compliance: Maintain the minimum bend radius for all cables exiting the tee. This prevents damage to insulation and ensures signal integrity for data and control cables .
4. Rung Spacing and Cable Securing: Use appropriate rung spacing (6–12 inches for small instrumentation cables) to secure cables and prevent movement at the tee junction .
5. Clearance and Accessibility: Position the tee to allow easy access for installation and maintenance, ensuring that covers (if used) can be removed without obstruction .

Material and Finish Considerations

Oblique tees are available in mild steel (pre-galvanized or hot-dip galvanized) and stainless steel (316L). The choice depends on environmental conditions, such as exposure to moisture, chemicals, or high temperatures . Ventilated or solid covers can be used depending on heat dissipation and dust accumulation requirements.

Best Practices

• Avoid placing tees in locations where cables would need to make sharp turns immediately after the junction.
• Ensure that the tee does not interfere with other structural elements or equipment.
• For long branch runs, consider intermediate supports to maintain tray strength and prevent excessive deflection .
• Document the tee positioning in the cable tray layout drawings for future maintenance and modifications. By following these guidelines, oblique tees can be positioned effectively to optimize cable routing, maintain system reliability, and comply with electrical design standards .