Indoor lighting, as an important component of smart homes, requires us to coexist with a large number of cables for lighting and controlling devices, even with advanced smart controls and wireless communication technologies. Before the realization of sci-fi technologies like ultra-long-distance wireless power transmission, indoor lighting circuits are mainly categorized into three types: exposed wiring, concealed wiring, and mixed wiring.

Exposed wiring refers to the method where the wiring is laid along the walls and ceiling surfaces without decorative ceiling panels, or where the wiring is laid along the outer surfaces of the walls and ceiling panels, making the wiring path visible.

Concealed wiring refers to the method where the wiring is laid inside the walls, decorative ceilings, or ceilings, making the wiring path invisible. In construction, indoor lighting sockets and low-voltage wires are fixed in conduits and cast in concrete slabs, which cannot be changed after pouring. In home decoration, conduits are usually channeled in the walls to reach sockets, switches, or small electrical boxes. When passing through an entire room, conduits are typically channeled in the floor. Conduits can also be run along the ceiling or the corners of the roof.

Mixed wiring is characterized by a portion of the wiring being visible while another portion is not. For example, in some indoor decoration projects, the electrical design may use concealed wiring for the wall sections and exposed wiring for the decorative ceiling sections.

Common wiring methods include direct wiring with insulated conductors, conduit wiring, and cable tray wiring.

1. Direct Wiring

When laying insulated conductors directly, two points should be noted:

1. For direct wiring indoors, sheathed insulated conductors should be used, with a cross-section not exceeding 6 mm², and the spacing between fixed points should not exceed 300 mm.

2. Direct or exposed wiring is strictly prohibited in building ceilings, walls, or columns; metal conduits and metal cable trays must be used.

2. Conduit Wiring

When laying insulated conductors in conduits, the voltage level should not be less than AC 750V.

1. For exposed wiring in humid environments or directly buried in soil, welded steel pipes should be used. For exposed or concealed wiring in dry environments, steel pipes with a wall thickness of not less than 1.5 mm or galvanized steel pipes can be used.

2. In environments with corrosive acid, alkali, or salt, flame-retardant plastic pipes should be used, but exposed wiring is not suitable in areas prone to mechanical damage. When concealed or buried, the section that emerges from the ground should have measures to prevent mechanical damage; in hazardous explosive environments, galvanized steel pipes should be used.

3. When three or more insulated conductors pass through the same conduit, the total cross-sectional area (including the outer sheath) should not exceed 40% of the net area inside the conduit. When two conductors pass through the same conduit, the internal diameter of the conduit should not be less than 1.35 times the sum of the diameters of the two conductors.

4. When electrical conduits and hot water or steam pipes are laid together, they should be placed below the hot water or steam pipes; if difficult, they can be placed above, with a distance of not less than 0.3 m from the hot water pipes and not less than 1.0 m from the steam pipes. The parallel clearance between electrical conduits and other pipes should not be less than 0.1 m.

5. For AC circuits passing through metal conduits, all phase and neutral wires should be in the same conduit.

3. Cable Tray Wiring

Cable tray wiring is suitable for dry areas that are not easily subject to mechanical damage. Cable trays can be made of plastic (PVC), metal, or floor-mounted types. Floor-mounted cable trays should have a distribution box or outlet every 4 to 8 meters. It is very easy to pull wires during installation, so there are no distance limitations. Strong and weak currents can share the same route through adjacent floor-mounted cable trays and can connect to their respective sockets in the same junction box. Of course, floor-mounted cable trays must be grounded and the product quality must meet standards. For large office or commercial hall areas, if computers are far from the walls, using long jumpers to connect directly to the information and power sockets on the wall is clearly inappropriate. In this case, leaving an outlet box near the floor-mounted cable tray can simultaneously solve the issues of network access and power supply.

With the improvement of living standards, home automation has become a common demand among people. Additionally, with the advancement of the Internet of Things, it is believed that integrated wiring will achieve significant breakthroughs in smart homes. As IoT technology enables the management and control of data, the development of smart homes will achieve greater success, while also driving integrated wiring to make significant progress in the application field of smart homes, keeping pace with life and adapting to its rhythm.