Proper Binding of Cable Trays

Proper cable binding in cable trays ensures organized, safe, and mechanically secure cable installations while maintaining electrical integrity.

Best Practices for Cable Binding

Cable ties and spacing: Cables within trays should be bound using cable ties at regular intervals to maintain neatness and prevent crossover. The spacing between ties should generally be three to four times the diameter of the cable bundle, and ties should be placed at entry and exit points, as well as at turning points in the tray. Avoid connecting multiple ties together, as this can reduce binding strength.

Excess tie length should be trimmed for safety and aesthetics. Bundle organization: Cables can be grouped by type or function, and large bundles may be further classified by column. This helps in identifying cable purposes and maintaining a tidy layout.

Use as long a bend radius as possible to prevent internal stress and potential cable damage. Mechanical support and accessories: Cable trays may include accessories such as clamps, protective rings, barrier strips, and covers to secure and separate cables. These accessories help prevent mechanical damage, maintain separation of different voltage or function cables, and support proper routing through bends, T-pieces, or reducers.

Grounding and bonding considerations: If the cable tray is metallic, it can serve as an Equipment Grounding Conductor (EGC). When using an EGC cable in the tray, it is recommended to bond it to each or alternate tray sections using grounding clamps. This ensures electrical continuity and prevents the EGC from being displaced under fault conditions.

For aluminum trays, avoid bare copper conductors to prevent electrolytic corrosion; insulated conductors with exposed ends at bonding points are preferred. Environmental and safety considerations: Cable trays and bindings should withstand environmental conditions such as moisture, temperature variations, and mechanical loads. Steel or stainless steel trays with appropriate galvanization are commonly used for corrosion protection.

By following these practices, cable trays can maintain organized, safe, and durable cable installations, reducing maintenance issues and ensuring compliance with electrical safety standards.