Cable tray with intermediate fixing

Intermediate fixing in cable trays ensures proper support, prevents sagging, and maintains safe cable management along the tray's length.

Purpose of Intermediate Fixing

Intermediate fixing points are used to support cable trays at intervals between main supports, preventing excessive deflection under the weight of cables and ensuring mechanical stability. They are essential for maintaining the integrity of the cable system, especially in long horizontal runs or when carrying heavy cables .

Types of Intermediate Supports

• Cable Tray Hangers: Suspended from ceilings or overhead structures to support horizontal tray runs .
• Wall or Side Brackets: Fixed to walls or vertical surfaces to provide lateral support .
• Centre Suspensions: Used for long spans to prevent sagging in the middle of the tray .
• Adjustable Clamps and Couplers: Allow secure attachment of trays to support elements and accommodate directional changes .

Spacing Guidelines

The spacing of intermediate supports depends on:

• Tray type: Ladder, ventilated, or solid-bottom trays have different load-bearing capacities .
• Cable weight: Heavier cables require closer support intervals.
• Tray material: Steel, aluminum, or fiberglass trays have varying stiffness . Typical spacing for steel ladder trays ranges from 1.5 to 3 meters, while solid-bottom trays may require supports every 1 to 2 meters. Always follow manufacturer recommendations and relevant standards such as BS EN 61537 .

Installation Considerations

• Ensure alignment of intermediate supports with the main tray to avoid twisting or uneven load distribution .
• Use compatible accessories like brackets, clamps, and couplers designed for the specific tray system .
• Check for environmental factors such as vibration, temperature, and corrosion, which may affect support performance .
• Avoid using cable trays as walkways; they are designed solely for cable support .

Accessories for Intermediate Fixing

• Mounting plates for junction boxes or devices .
• Barrier strips or covers to protect cables at support points .
• Plastic or metal fasteners for securing cables to the tray . Proper intermediate fixing ensures safe, durable, and efficient cable management, reducing the risk of cable damage and maintaining compliance with electrical installation standards.