Wire Conduit Layout in Precast Slab Houses

The wire conduit layout in precast slab houses should prioritize safe locations, strictly adhere to construction specifications, avoid damaging the floor slab structure, and adopt alternative solutions when necessary.

I. Prioritize Safe Locations

1. Joint Positions: After precast slabs are installed, the joints between slabs are ideal areas for embedding conduits. Before construction, debris in the joints should be cleared. After conduit laying, fine aggregate concrete should be used to fill and compact the joints, ensuring conduits are fixed without compromising the integrity of the floor slab.
2. Recessed Areas at Slab Ends: Some precast slabs are designed with recessed areas at both ends. Conduits can be directly embedded into these recesses, making construction convenient and not affecting subsequent decorative layer construction.
3. Within Local Cast-in-Place Layers: In areas such as kitchens and bathrooms where cast-in-place layers (e.g., concrete protective layers above waterproofing layers) are poured, conduits can be embedded within them. This meets waterproofing requirements and avoids interference with the main structure of the precast slabs.

II. Avoid Damaging the Floor Slab Structure

1. Prohibit Slotting in Precast Slab Bodies: Precast slabs are hollow structures. Slotting can damage their load-bearing capacity and pose safety hazards. If concealed wiring is required, it must be achieved through joints, recesses, or cast-in-place layers.
2. Accurately Position Junction Boxes: If holes need to be chiseled in the floor slab to install junction boxes, infrared or chalk lines should be used for positioning in advance to avoid steel bar positions. The chiseled hole diameter should be less than 1.5 times the outer diameter of the conduit to prevent weakening the load-bearing capacity of the floor slab.

III. Construction Specification Requirements

1. Conduit Spacing: The spacing between two parallel conduits should be at least 25mm (10mm is allowed in some regions) to ensure that the concrete can fully wrap around the conduits and avoid voids.
2. Crossing Restrictions: Three or more conduits should not cross at the same point to prevent insufficient local concrete thickness from causing deformation of the floor slab steel bars.
3. Bending Radius: The minimum bending radius of conduits should be 6 times the pipe diameter. If embedded in concrete, it should be expanded to 10 times to avoid cracking at the bends.
4. Conduit Fixation: All conduits must be clamped between the upper and lower layers of steel bars in the floor slab, with no more than three layers stacked to prevent local pressure from collapsing the floor slab.

IV. Alternative Solutions

1. Utilize Ceiling Space: In areas with suspended ceilings, conduits can be fixed to the ceiling joists. Flame-retardant PVC pipes or metal pipes should be used, and their insulation performance should meet standards.
2. Wall Slotting: When slotting walls (e.g., lightweight partition walls) for wiring in non-load-bearing walls, the slot depth should not exceed one-third of the wall thickness, and the width should not exceed 1.5 times the outer diameter of the conduit. After wiring, the slots should be filled with cement mortar and reinforced with mesh to prevent cracking.

Summary: The wire conduit layout in precast slab houses should prioritize safety, preferentially selecting joints, recesses, or cast-in-place layers, strictly adhering to specifications such as conduit spacing and crossing restrictions, and avoiding damage to the floor slab structure. If conditions are limited, alternative solutions such as utilizing ceiling space or wall slotting can be combined to ensure construction compliance and long-term safety.