Lighting Distribution System Diagram

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Lighting Distribution System Diagram. It is a simplified diagram that uses graphic symbols and letter symbols to depict the composition and connection methods of the lighting system, and it can intuitively reflect the power supply mode, cable laying, equipment installation and other situations of the lighting system. The following are some basic methods and key points for reading the lighting distribution system diagram:

### Recognize Graphic Symbols and Letter Symbols
- **Graphic Symbols**: Common ones include the graphic symbol of the distribution box, which is usually represented by a rectangular frame, and the number and model of the distribution box are marked inside the frame; the graphic symbols of various lamps, for example, fluorescent lamps are usually represented by a straight line with several short horizontal lines in the middle, and incandescent lamps are represented by a circle with a dot in the middle; the graphic symbols of switches, for example, a single-pole switch is represented by a vertical line, and a double-pole switch is represented by two vertical lines; the graphic symbols of sockets, for example, a single-phase socket is represented by a circle with a vertical line and three short horizontal lines in the middle.
- **Letter Symbols**: They include the model and specification of the distribution box. For example, PZ30 represents a modular terminal combined electrical distribution box. The markings of lamps, for example, "FL 2×36W" indicates fluorescent lamps with a power of 2×36 watts. The markings of switches, for example, "SA1" indicates that the switch number is SA1. The markings of sockets, for example, "XS1" indicates that the socket number is XS1, as well as the markings of cable laying methods, pipe diameters, conductor models, etc. For example, "BV-3×2.5-SC20-WC" represents copper-core polyvinyl chloride insulated wires, with 3 wires of 2.5 square millimeters,穿直径20毫米的焊接钢管, and laid concealed along the wall.

### Understand the Distribution Box
- **Position and Number of the Distribution Box**: In the system diagram, first find the graphic symbol of the distribution box, check the marked number and position description to determine the position and function of the distribution box in the entire lighting system.
- **Internal Structure of the Distribution Box**: Check the graphic symbols and letter markings of electrical components such as switches, fuses, contactors, etc. inside the distribution box to understand its configuration and functions. Generally, information such as the rated current, number of poles, controlled circuits of each switch, and the rated current of the fuse will be marked.

### Check the Lines
- **Direction and Connection of the Lines**: For the lines led out from the distribution box, follow the direction of the lines to check the lamps, switches, sockets and other equipment connected to them, and understand the electrical connection relationship between various equipment. Lines are usually represented by straight lines, and sometimes broken lines or arcs are used to represent the turning or branching of lines.
- **Markings of the Lines**: Carefully check the letter markings on the lines to understand information such as the laying method of the lines, conductor model, cross-sectional area, pipe diameter, etc. This is very important for construction and maintenance. For example, "BV-3×4-SC25-FC" represents using 3 copper-core polyvinyl chloride insulated wires with a cross-sectional area of 4 square millimeters,穿直径25毫米的焊接钢管, and laid concealed along the floor.

### Analyze Lamps, Switches and Sockets
- **Lamps**: Check the graphic symbols and letter markings of lamps to understand information such as the type, power, installation height, and installation method of the lamps. For example, "FL 1×40W 3m CH" indicates a 40-watt fluorescent lamp with an installation height of 3 meters and installed in a chain-hung manner.
- **Switches**: Pay attention to information such as the type, number of poles, and controlled lamps of the switches. A single-pole switch generally controls one lamp or a group of lamps, and a double-pole switch can be used to control lamps with higher power or control multiple lamps simultaneously. For example, "SA1 1P 10A" represents a single-pole switch with a rated current of 10 amperes, controlling one lighting circuit.
- **Sockets**: Understand information such as the type, rated current, and installation height of the sockets. Common sockets include single-phase sockets, three-phase sockets, sockets with grounding poles, etc. For example, "XS1 10A 250V" represents a single-phase socket with a rated current of 10 amperes and a rated voltage of 250 volts, and the general installation height is 0.3 meters from the ground or according to specific design requirements.

### Understand the Power Supply Mode and Control Mode of the System
- **Power Supply Mode**: Check the introduction method of the power source in the system diagram and the connection relationship between the distribution boxes to determine whether the lighting system adopts single-phase power supply, three-phase four-wire power supply or other power supply modes. Generally, small lighting systems mostly adopt single-phase power supply, while large commercial or industrial lighting systems may adopt three-phase four-wire power supply.
- **Control Mode**: Analyze the control mode of the lamps, whether it is a single switch controlling one lamp or multiple switches controlling a group of lamps through series, parallel or other connection methods. Meanwhile, pay attention to whether an intelligent lighting control system is adopted, such as realizing the control of lamps through remote controllers, sensors, timers, etc.