Cable tray construction at a Mongolian steel plant

Cable tray installation in a steel plant requires careful planning, proper support fabrication, precise alignment, grounding, and adherence to safety and technical standards.

Planning and Material Preparation

Before installation, review approved shop drawings to determine tray layout, lengths, and locations in electrical rooms, plant areas, and service corridors . Inspect all materials, including GI or perforated cable trays, ladders, and accessories, for damage or discrepancies, and remove unsuitable items from the site . Store trays horizontally on flat surfaces with timber supports at 1-meter intervals, protecting them from moisture and sunlight . Ensure all tools and equipment comply with contract requirements.

Support Fabrication and Installation

Fabricate MS support structures using wall-mounted angles (e.g., 50 x 50 mm, 6 mm thick) or C-channels for bridge sections, spaced at 1-meter intervals . Fasten supports with high-strength bolts (e.g., Hilti nuts and bolts, minimum 75 mm) and weld bridge supports where necessary . Apply primer and enamel paint to welded areas to prevent corrosion . Ensure supports are designed to carry the full load of installed cables and allow for future cable additions .

Tray Installation

Install cable trays, ladders, and trunking according to shop drawings and site requirements, ensuring they are level, vertical, and parallel with building features . Use appropriate bolts and cleats for load-bearing vertical trays, and maintain a minimum distance of 300 mm from process piping . Provide support for all joints, bends, Tees, and reducers at intervals of 300 mm, and maintain the minimum permissible bend radius for cables . Remove burs and sharp edges, and apply galvanized paint to cut edges to prevent rusting .

Grounding and Safety

Install earth continuity strips at all joints and connect a separate grounding cable to the earth bar . Ensure all operatives have completed safety induction and competency verification, and monitor work for compliance with safety standards . Do not proceed in unsafe conditions, and retrain personnel if necessary.

Cable Laying and Termination

For high-voltage and control cables, lay cables in trays or HDPE conduits, ensuring proper isolation using G-10 or FRP sheets at each support . Use high-tensile bolts, washers, and coupler plates for tray joints, and provide bends of adequate radius to accommodate cable routing . Ensure that cable trays are not used as walkways and are protected from severe physical damage .

Quality Assurance

Follow inspection and test plans, and document all installation activities. QC inspectors should verify that installation meets specifications, technical scope, and approved drawings . Ensure that the cable tray system is continuous, mechanically stable, and capable of supporting the intended cable load. By following these steps, a Mongolian steel plant can achieve a safe, durable, and compliant cable tray installation suitable for high-voltage and control systems, while allowing for future expansion and maintenance.