How to install cable trays with intermediate joints

Intermediate joints are used to connect sections of cable trays, ensuring mechanical stability, electrical continuity, and proper alignment throughout the tray run.

Purpose of Intermediate Joints

Intermediate joints in cable tray systems serve to: Connect two tray sections securely, maintaining structural integrity. Ensure electrical continuity for grounding and bonding across the tray system. Allow for thermal expansion and contraction, preventing stress on cables and tray components.

Maintain alignment along long runs, especially in industrial or commercial installations where tray lengths exceed standard sections.

Types of Intermediate Joints

Splice Plates or Connector Plates: Flat metal plates bolted across the ends of two tray sections. They provide rigid mechanical support and are commonly used in ladder and ventilated trough trays. Coupler Fittings: Pre-fabricated fittings designed to join tray sections, often including pre-drilled holes for bolts and grounding connections.

These are used for straight runs or slight misalignments. Expansion Joints: Special joints that accommodate thermal expansion in long tray runs, preventing deformation or cable stress.

Installation Best Practices

Alignment: Ensure tray ends are flush and level before bolting the joint. Misalignment can cause cable snagging or uneven load distribution. Bolting: Use manufacturer-recommended bolts and torque specifications to secure splice plates or couplers.

Typically, multiple bolts per side are used for stability. Grounding and Bonding: Maintain electrical continuity by connecting bonding jumpers across the joint if the tray is metallic. This prevents potential voltage buildup and ensures safety.

Support Spacing: Intermediate joints should be supported according to the tray's load rating. Standard support spacing is often 3–3. 6 meters for center-hung trays, but always follow manufacturer specifications.

Inspection: After installation, check for proper alignment, secure bolting, and continuity of grounding. This reduces the risk of mechanical failure or electrical hazards. Compliance and StandardsBS EN 61537: Specifies requirements for cable tray systems, including mechanical strength and joint integrity.

NE

C Article 392: Governs installation, support, and bonding of cable trays in the U. S., including proper joint connections. Manufacturer Guidelines: Always follow the specific tray manufacturer's instructions for joint installation to ensure warranty and safety compliance.

Intermediate joints are critical for the reliability and safety of cable tray systems, particularly in long or heavily loaded runs. Proper selection, installation, and inspection of these joints ensure that the tray system can support cables safely, maintain electrical continuity, and accommodate environmental factors such as thermal expansion.