Elevator cabling can be safely supported on cable trays if proper design, load capacity, spacing, and code compliance are followed.

Cable Tray Selection and Material

Elevator cables are typically heavy and may carry high currents, so selecting a robust cable tray is essential. Common materials include steel, aluminum, and fiber-reinforced plastic (FRP), with aluminum being widely used due to its corrosion resistance and strength-to-weight ratio . The tray type can be ladder, ventilated trough, or solid-bottom, depending on the cable type, heat dissipation requirements, and environmental conditions . For elevator applications, ladder or ventilated trays are preferred to allow airflow and reduce heat buildup.

Load Capacity and Support

Cable trays must be designed to support the weight of elevator cables over the span between supports. Trapeze or swing supports are commonly used, with vertical hangers and cross members ensuring the tray remains level and stable . The spacing of supports should follow manufacturer recommendations and account for the weight and number of cables, typically with rung spacing of 150–230 mm (6–9 inches) for proper cable support . Overloading trays can lead to structural failure or cable damage.

Installation Guidelines

1. Plan the layout: The system designer should consider building codes, elevator specifications, and clearances from other trades .
2. Secure attachment: Use tray clips, hex nuts, and washers to attach trays to hangers, ensuring horizontal and vertical alignment .
3. Maintain bend radius: Elevator cables must not be bent beyond their minimum bend radius to prevent insulation damage .
4. Avoid human load: Cable trays are not designed to support personnel; they are strictly for cable support .
5. Environmental considerations: Choose materials and finishes suitable for the environment, such as galvanized steel for moisture-prone areas .

Compliance and Safety

Elevator cable installations on trays must comply with the National Electrical Code (NEC) Article 392, OSHA regulations (29 CFR 1910.305), and any local building codes . Only qualified personnel should perform installation, and all wiring methods must be listed for use in cable trays. Flexible cords are prohibited as a replacement for fixed wiring due to fire and insulation degradation risks .

Best Practices

• Use ventilated trays to prevent heat accumulation.
• Plan for future expansion by sizing trays for additional cables.
• Ensure proper grounding and bonding of trays to prevent electrical hazards.
• Regularly inspect and maintain trays to detect corrosion, loose fittings, or cable damage. By following these guidelines, elevator cabling can be safely and efficiently installed on cable trays, ensuring compliance, reliability, and long-term performance.