Double-layer hanging installation of cable trays in communication equipment rooms

Double-layer cable tray installations require careful planning, proper vertical separation, and secure support to ensure safety, signal integrity, and compliance with standards.

Planning and Design

Before installation, obtain approved shop drawings showing the cable tray route, dimensions, installation height, support system, number of layers, and the type of cables each tray will carry. For communication equipment rooms, it is common to use a two-layer system: the bottom layer for power or electrical circuits (solid bottom tray) and the upper layer for structured cabling or communication cables (basket tray),.

Layer Separation

Maintain a minimum vertical distance of 30 cm between the two layers to prevent electromagnetic interference between power and communication cables. This separation also allows for easier maintenance and future cable additions.

Support and Hanging

Cable trays should be securely supported from the ceiling or structural elements using hangers, rods, or brackets designed for the tray type and load. Supports must account for the weight of the cables, tray, and any imposed loads, and should follow manufacturer specifications and relevant standards such as BS EN 61537. Cable ManagementTie-downs: Cables should be tied down to maintain spacing, prevent sagging, and ensure compliance with NEC requirements, especially for vertical runs.

Spacing: Power cables should be spaced at least one cable diameter apart to approximate free-air ampacity, while communication cables may be bundled but should avoid excessive compression. Routing: Check for clashes with HVAC ducts, fire protection pipes, and other services. Coordination meetings with engineers may be necessary to resolve conflicts before installation.

Material Selection

Choose tray materials based on the environment: pre-galvanized or hot-dip galvanized steel for indoor use, aluminum for lightweight and corrosion resistance, or FRP for highly corrosive environments. Covers may be used for additional protection or EMI shielding.

Installation Steps

Verify shop drawings and material availability. Mark tray routes and support locations on-site. Install hangers and supports according to load calculations.

Mount the bottom tray first, ensuring level alignment. Install the upper tray, maintaining the required vertical separation. Secure cables with tie-downs and maintain proper spacing.

Perform final inspection to ensure compliance with standards and safety. Following these guidelines ensures a safe, organized, and flexible cable tray system that supports both power and communication cabling while allowing for future expansion and maintenance.