Cable trays installed through walls with sleeves

Cable tray sleeves provide a secure, fire-rated, and code-compliant method for routing trays through walls while maintaining structural and fire safety.

Purpose of Wall Sleeves

Wall sleeves are used to facilitate cable tray penetration through walls while maintaining fire-resistance, structural integrity, and ease of maintenance. They act as a rigid support for the tray and allow for firestopping materials to be applied effectively, preventing smoke and fire from spreading between rooms or floors . Sleeves also accommodate thermal expansion, seismic movement, and grounding requirements.

Selection of Sleeves

• Material: Steel sleeves are commonly used for heavy-duty support and grounding compliance per NEC 392.60 .
• Size: The sleeve should be slightly larger than the cable tray to allow for firestop packing and expansion. For example, a 4” x 12” tray may require a 7” x 15” opening .
• Fire Rating: Choose UL-listed or ETL-approved sleeves compatible with the wall's fire rating. Firestop kits or intumescent caulks can be used to match the wall's rating .
• Outdoor Use: For exterior walls, weatherproof conversion kits are available to protect against moisture .

Installation Steps

1. Prepare the Wall Opening: Cut a clean, square opening slightly larger than the tray. For large openings, install a fire-resistant backing plate to support firestop materials .
2. Install the Sleeve: Insert the steel or approved sleeve into the wall, ensuring it is plumb and aligned with the tray on both sides .
3. Route the Cable Tray: Stop the tray a few inches short of the wall on each side to allow for firestop material installation .
4. Firestopping: Fill the gap between the tray and sleeve with firestop packs, mineral wool, or intumescent caulk. Ensure no visible cracks or voids remain, and the packing thickness meets the required specifications (typically ≥24 cm for large openings), .
5. Grounding: If the tray requires grounding, run a ground wire through the sleeve to isolate it from communication cables .
6. Cover Plates: Install square, painted cover plates to close the opening neatly and maintain fire rating .

Maintenance and Considerations

• Seismic and Thermal Movement: Sleeves allow the firestop material to expand or contract without compromising the seal .
• Inspection: Periodically check for cracks, voids, or dislodged firestop material, especially in high-traffic or seismic areas.
• Retrofit: Sleeves simplify retrofitting or adding additional cables without compromising fire safety . Using wall sleeves ensures compliance with fire codes, NEC grounding requirements, and structural safety, while providing a practical solution for cable tray penetrations through walls.