Cable hole wrapping on top of cable tray

Top-side cable tray wrapping is an effective fire protection method using specialized wraps like PROMASEAL® SupaWrap or FireMaster Cable Wrap, installed with proper fixings and sealants to maintain fire resistance.

Purpose of Cable Tray Wrapping

Cable tray wrapping is primarily used to protect cables from fire exposure, maintain the integrity of electrical systems, and comply with fire safety standards. Wrapping can prevent heat damage, maintain circuit continuity, and reduce smoke and flame spread in industrial or sensitive environments. Top-Side-Only WrappingFor cable trays penetrating fire-rated walls or concrete slabs, top-side-only wrapping is a recognized method.

The PROMASEAL® SupaWrap, for example, can be installed only on the top of the cable tray, fixed to the wall on each side with screws and washers, and sealed with acrylic sealant at the joints. No sealant is required at the top of the wrap itself. This method maintains a fire rating of FRL -/120/120 when used with a bulkhead sealer system.

It is suitable for PVC or XLPE insulated power cables with copper conductors.

Full Encapsulation Wrapping

Products like FireMaster Cable Wrap provide full encapsulation using glass fiber reinforced aluminum foil. Installation involves overlapping blankets, sealing cut edges, and securing with stainless steel bands at specified intervals. This method ensures extended fire exposure protection and is particularly useful for high-risk or critical installations.

Installation Considerations

Fixings: Use screws and washers at recommended spacing (e.g., 100mm and 500mm above the batt face for SupaWrap) or stainless steel bands for FireMaster wraps. Spacing: Maintain proper spacing to prevent sagging and gaps, typically 8–12 inches between bands. Sealants: Use compatible acrylic or fire-rated sealants at joints to ensure continuity of protection.

Cable Types: Confirm compatibility with cable insulation (PVC, XLPE) and conductor type (copper or steel) to ensure fire test results are applicable. Tray Type: Ventilated or solid-bottom trays can be wrapped, but ensure the wrap does not interfere with heat dissipation or cable bend radius. ApplicationsTop-side or full-wrap solutions are widely used in industrial, nuclear, and commercial projects, particularly where fire safety is critical.

They can be applied to cable trays, conduits, and ventilation ducts, providing flexible solutions for various construction environments. SummaryTop-side cable tray wrapping is a practical and tested fire protection method. Choosing between top-side-only or full encapsulation depends on the fire rating requirements, cable type, and installation environment.

Proper fixings, sealants, and adherence to manufacturer guidelines are essential to maintain fire resistance and system integrity.