Will fire cable trays enter the low-voltage electrical room

Yes, fire-rated cable trays can be run through a low-voltage electrical room, provided proper firestopping, separation, and installation standards are followed.

Firestopping Requirements

When cable trays pass through walls, floors, or slabs, all openings must be sealed with firestopping materials to maintain the fire-resistance rating of the barrier . This includes using fire-rated boards, firestop packs, firestop mastic, or mineral wool. Gaps around cables or trays should be minimal, and large openings may require a fire-resistant backing plate before sealing . Proper installation ensures that fire and smoke cannot spread through penetrations, which is critical in low-voltage rooms that often house sensitive equipment .

Low-Voltage Cable Considerations

Low-voltage cables, such as data, telecom, or security wiring, can be run in cable trays or J-hooks within a low-voltage electrical room . These cables do not always require full conduit protection unless passing through fire-rated walls or ceilings. When penetrating fire-rated barriers, it is common to use EMT sleeves or preformed firestop elements and fill gaps with fire caulk, putty, or firestop pillows to maintain the fire rating . This approach also allows for future upgrades without compromising fire safety.

Tray Installation and Separation

Cable trays should be mechanically secure, level, and plumb, with sufficient width and strength to support the cables . It is recommended to segregate low-voltage and high-voltage cables to reduce electromagnetic interference and maintain safety . Fire-resistant steel plates or coatings may be applied to trays in areas requiring higher fire protection .

Best Practices

• Reserve openings slightly larger than the tray dimensions to allow proper firestopping .
• Layer fire-blocking materials carefully to create a dense, compact barrier .
• Ensure all firestop materials are installed without gaps and finished smoothly for both safety and aesthetics .
• Use pretested firestop devices (e.g., CP 653 BA speed sleeve, CFS-BL firestop block) to simplify maintenance and ensure compliance with standards like UL 1479 and EN 1026 . By following these guidelines, fire-rated cable trays can safely pass through a low-voltage electrical room while maintaining fire compartmentation and compliance with building codes.