Are there cable trays for electrical equipment inside the shaft

Cable trays in electrical shafts provide structured support, protection, and fire safety for power and communication cables, ensuring compliance with technical and fire regulations.

Purpose and Function

Cable trays are engineered support systems designed to route, support, and protect insulated electrical cables used for power distribution, control, instrumentation, and communication. Unlike conduits, they allow cables to be laid in bundles, improving accessibility, heat dissipation, and scalability of the electrical system ( ). In electrical shafts, cable trays help organize vertical cable runs while maintaining structural integrity and safety.

Types of Cable Trays

Common types suitable for shafts include: Ladder trays: Two side rails connected by rungs, ideal for heavy cables and good ventilation ( ). Solid-bottom trays: Provide full protection against dust and debris, suitable for sensitive environments ( ). Ventilated trays: Allow airflow to dissipate heat, reducing the risk of overheating ( ).

Wire mesh trays: Lightweight, flexible, and easy to install in tight shaft spaces ( ). Material selection depends on the environment: galvanized steel, stainless steel, aluminum, or fiberglass-reinforced plastic are commonly used for corrosion resistance and mechanical strength ( ).

Installation Considerations

Supports and suspension: Cable trays must be securely supported using hangers, brackets, or shaft-specific suspension systems. Pre-galvanized, hot-dip galvanized, or painted supports are used depending on environmental conditions ( ). Layout: Position trays to allow reasonable access for installation and maintenance, avoiding sharp bends and ensuring proper load distribution ( ).

Floor and slab penetrations: At floor level or slab penetrations, install a waterstop of at least 50 mm and provide 20–30 mm of firestopping with a fire-support plate at the top ( ).

Fire Safety and Compliance

Electrical shafts require strict fire protection measures: Use fire-rated boards, firestop packs, firestop mastic, or mineral wool to seal gaps around trays ( ). Ensure tight sealing without visible cracks, with packing thickness not less than 24 cm and gaps around cables under 1 cm² ( ). Cover plates should be square, consistent, and painted to maintain fire integrity ( ).

Firestopping ensures that vertical cable runs do not compromise the shaft's fire-resistance rating.

Best Practices

Select tray type based on cable weight, heat generation, bend radius, and environmental exposure ( ). Maintain clear labeling and separation of power and communication cables to reduce interference. Regularly inspect trays for corrosion, mechanical damage, and firestop integrity.

Follow national and international standards (e.g., UL, NEMA, CE marking) for material and installation compliance ( ). By following these guidelines, cable trays in electrical shafts can provide safe, organized, and code-compliant cable management, ensuring both operational efficiency and fire safety.