Cross-connections are generally not required for trough-type cable trays unless additional structural support or grounding continuity is needed.

Structural Considerations

Trough-type cable trays feature a continuous or partially ventilated bottom with solid side rails, providing moderate structural strength and continuous cable support . Unlike ladder trays, which have rungs that can be cross-connected for added rigidity, trough trays are designed to support cables along their length without the need for transverse cross-connections under normal loading conditions . Cross-connections may be considered if:

• The tray spans unusually long distances without intermediate supports.
• Heavy or densely packed cables are installed that could cause sagging.
• Local building codes or engineering specifications require additional reinforcement.

Grounding and Electrical Continuity

While mechanical cross-connections are not typically required, electrical continuity and grounding are critical. According to NEC Article 392, metallic cable trays must maintain proper grounding throughout the system . This can be achieved using:

• Factory-installed bonding jumpers or connectors.
• Grounding lugs at tray joints.
• Cross-bonding where multiple trays intersect to ensure a continuous path to ground. Cross-connections in this context are primarily for bonding and grounding purposes, not structural support.

Best Practices

• Follow manufacturer recommendations for tray spans, supports, and load ratings .
• Use splice plates or brackets at joints to maintain alignment and mechanical stability.
• Ensure grounding continuity across all tray sections, especially at tees, crosses, and bends.
• Avoid unnecessary cross-connections that could complicate installation or interfere with cable routing.

Conclusion

For standard trough-type cable trays, mechanical cross-connections are not typically required, as the tray design provides sufficient support. However, cross-connections may be implemented for enhanced structural support or grounding continuity in specific installations, particularly for long spans, heavy cable loads, or compliance with local electrical codes . Proper planning and adherence to manufacturer and NEC guidelines ensure both mechanical stability and electrical safety.