Cable conduits passing through cable trays should be properly supported, protected with bushings, and sealed to prevent damage and maintain code compliance.

Key Principles

When conduits pass through cable trays, the main goals are to protect cables from mechanical damage, ensure proper support, and maintain electrical safety. Cable trays are designed to support cables but not to enclose or fully protect them, so conduits must be carefully integrated to avoid stress on the cables and maintain accessibility for maintenance .

Methods for Transitioning Conduits

1. Bushed Conduit Entry: Use a bushed conduit or tubing when cables leave the tray and enter equipment. The bushing protects the cable insulation from sharp edges and prevents abrasion . This method is compliant with NEC 2020 Section 392.46, which allows conductors to enter equipment through bushed conduits without requiring a junction box .
2. Flanged Opening Entry: Cables can also transition through a flanged opening on top of the equipment. The flange should be smooth or fitted with a protective grommet to prevent cable damage. Both bushed and flanged openings should be sealed with duct seal or similar material to prevent debris from entering the enclosure .

Installation Best Practices

• Inspect and Prepare: Before installation, inspect trays and conduits for damage and ensure the layout matches approved drawings .
• Support and Alignment: Maintain proper alignment of conduits with the tray. Use supports or clamps to prevent sagging or undue stress on cables .
• Cable Protection: Ensure all edges where conduits pass through trays are smooth or protected with bushings. Avoid sharp bends that could damage insulation .
• Labeling and Zoning: Clearly label conduits and cables, and separate power, signal, and control cables to prevent interference .
• Documentation: Record the installation, including photographs and inspection results, to ensure compliance and facilitate future maintenance .

Additional Considerations

• Spacing and Ventilation: Maintain adequate spacing between conduits and cables to allow heat dissipation and prevent overcrowding .
• Code Compliance: Follow NEC Article 392 and local electrical codes for tray and conduit installations, including grounding and bonding requirements .
• Maintenance Access: Ensure that conduits do not obstruct access to other cables or equipment for future maintenance . By following these methods and best practices, conduits can safely pass through cable trays while protecting cables, maintaining system reliability, and ensuring compliance with electrical standards.