Elbows in cable trays are installed to change the direction of the tray while maintaining proper support, bending radius, and compliance with electrical standards.

Purpose of Elbows

Elbows are used in cable tray systems to navigate changes in direction, such as horizontal or vertical turns, without compromising the integrity of the cable layout or the tray system. They allow cables to follow the designed path while avoiding sharp bends that could damage insulation or conductors.

Support Requirements

Proper support is critical for elbows. Supports should be positioned according to NEMA VE 2 standards, typically near the elbow and at intervals along the tray to prevent sagging or stress on the cables ( ). For horizontal or vertical elbows, supports are often placed just before and after the elbow, ensuring the elbow section is stable and the load is evenly distributed. Maximum support distances are determined by the tray type, cable weight, and manufacturer specifications.

Bending Radius Considerations

The bending radius of the elbow must match or exceed the minimum bending radius of the largest cable in the tray ( ). This prevents cable damage during installation and ensures long-term reliability. When multiple cables are installed, the largest bending radius governs the elbow design.

Splice Plate and Connector Placement

Elbows often require splice plates or connectors to join sections. These should not be placed at the midpoint of the span or directly on supports; instead, they are ideally installed at one-quarter of the span between supports to reduce stress and maintain mechanical integrity ( ).

Grounding and Bonding

Cable tray elbows must maintain electrical continuity. Bonding jumpers should be installed at each elbow if it forms part of a continuous tray run, and grounding should comply with NEC and NEMA standards ( ). This ensures safety and prevents electrical hazards.

Summary

When installing elbows in cable trays:

• Position supports near the elbow and at proper intervals.
• Ensure the elbow radius meets or exceeds the minimum cable bending radius.
• Install splice plates at one-quarter points between supports, not at midpoints.
• Maintain proper bonding and grounding for electrical continuity.
• Follow NEC, NEMA VE 2, and manufacturer guidelines for safe and compliant installation. Proper installation of elbows ensures mechanical stability, cable protection, and electrical safety throughout the cable tray system.