Installation of parallel elbows on cable trays

Parallel elbows on cable trays must be properly supported, bonded, and spaced according to standards to ensure mechanical stability and electrical safety.

Support and Positioning

Parallel elbows, which change the direction of cable trays horizontally or vertically, require dedicated support points to prevent sagging or undue stress on cables. Supports should be positioned so that the elbow is not suspended solely by the tray ends; ideally, supports are placed near the elbow junctions and at intervals recommended by NEMA VE 2 or the manufacturer's instructions . Avoid placing connectors at the center of spans; instead, position them between the support point and the quarter-point of the span .

Bonding and Grounding

All cable tray elbows must be bonded to maintain electrical continuity. Install bonding jumpers at each elbow and expansion joint, and ground the tray system at least every 15 meters (50 feet) and at both ends . For conduit drop-outs connected to elbows, use a grounding bushing or a bonding wire bolted to the tray to ensure proper electrical safety .

Installation Best Practices

• Use manufacturer-approved components: Only use elbows and fittings designed for the specific tray system to ensure compatibility and structural integrity .
• Maintain cable bend radius: Ensure that cables exiting the elbow do not exceed their minimum bend radius to prevent damage .
• Secure cables within the tray: Use cable ties or bands to prevent movement, especially in vertical elbows where gravity can cause slippage .
• Allow for expansion: In long runs or outdoor installations, provide expansion connectors at intervals (typically 30 meters or 100 feet) to accommodate thermal expansion .

Compliance and Safety

Follow relevant standards such as NEMA VE 2, NEC, BS EN 61537, and manufacturer guidelines for installation. Ensure that all components are rated for the environment, including corrosion resistance and mechanical load capacity . Proper installation of parallel elbows not only maintains cable integrity but also ensures the overall safety and reliability of the electrical system. By adhering to these guidelines, parallel elbows can be installed efficiently, providing smooth cable routing while maintaining mechanical and electrical safety.