Sharing of wiring trough and cable tray laying techniques

1. Conduit Trench Selection Criteria
The selected conduit trench must comply with the design scheme and construction process requirements, with the closest possible spacing to facilitate assembly and maintenance.

a. Inspect all openings on the conduit trench route according to the design drawings. Establish the conduit trench path based on actual site conditions to avoid conflicts with other specialized conduits.

b. Use an ink line marker to lay out reference lines on the ceiling or wall, ensuring the conduit trench runs in a straight horizontal or vertical line from start to end point.

2. Support Frame Assembly

a. Mark installation hole positions on the ceiling or wall, drill holes, and drive expansion bolts firmly into place. Fix the frame at 1.5-meter intervals.

b. Align the support frame with the hole positions, adding flat washers, spring washers, and screws. One worker should support the frame while another ensures it is level or plumb, then secures the screws without fully tightening them.

c. Assemble another set of support frames at the opposite end of the straight section. Use a tightly drawn braided line between the upper, lower, left, and right support frames to align the entire assembly. Use this line as a reference to adjust intermediate support frames. The spacing between supports at the start/end of the conduit trench, corners, junctions, and terminal boxes must not exceed 0.5 meters.

3. Steel Trough Assembly

a. The conduit trench connection must be continuous and unbroken. Each section of the trench must have at least two supports. Supports must be installed and firmly fixed to the wall at corners, support points, and endpoints.

b. Use connecting plates to join straight sections of the steel trough, fastening with pan-head screws from the inside out. Add flat washers, spring washers, and nuts, ensuring the joint is flush and tightly sealed. After removing contaminants from the steel trough, cover it with a lid that is flush, intact, and free of warped edges.

c. When fastening screws or other hardware to the conduit trench, the tightened components should sit flush with the inner surface without protruding.

d. Use elbows, tees, crosses, and reducers for turns and branches in the steel trough. Open ends must be sealed with cover plates. Outlets should be properly positioned, smooth, and free of burrs.
The installed conduit trench must be straight and neat, with a maximum allowable deviation of 2% of its length horizontally or vertically, and a total length deviation not exceeding 20 mm.

e. Reserve crossover wiring space on both sides of the conduit trench and allow for expansion capacity. Grounding should use copper braided wire; the metal trough itself must not be used as equipment grounding conductor. Single-point grounding is preferred for conductor troughs.

4. Treatment of Steel Trough Penetrations

Steel troughs must not be connected within walls or floors, nor covered with concrete. After cable pulling, all wall or floor penetrations must be fire-stopped with sealants and finished with wall-matched water-based paint.

Cable tray installations must be level, vertical, and flat-surfaced, with secure fastening, tightly fitted covers, and logically ordered supports for a clean and professional appearance. Bridge grounding must meet standards. Anti-loosening nuts should be added to the cable tray, and supports must be reliably connected. Apply anti-rust paint where contact surfaces are exposed.