How to wire the control cabinet

In industrial automation system, as the core carrier of electrical equipment, the standardization and rationality of its internal wiring directly affect the stability and maintenance efficiency of the system. Good wiring can not only improve the reliability of equipment operation, but also provide convenience for later maintenance and troubleshooting. This paper will introduce in detail the basic principles, steps and matters needing attention of control cabinet wiring.

First, the preparation work before wiring

Before wiring the control cabinet, sufficient preparations must be made. Including:
　　. Drawing review: read the electrical schematic diagram, wiring diagram and layout diagram carefully to ensure that the function and wiring mode of each component are understood.

2. Material preparation: Prepare wires, terminal blocks, trunking, cable ties, labels and other materials with corresponding specifications according to the drawings.

3. Tool inspection: Prepare tools such as wire stripper, wire crimper and screwdriver to ensure that the tools are intact.

4. Wiring planning: determine the wiring path according to the equipment layout to avoid cross interference.

Second, the basic principles of wiring

1. Separation of strong and weak electricity
　　trong electric lines (such as main power supply and motor control line) should be wired separately from weak electric signal lines (such as PLC input and output lines and sensor signal lines) to prevent electromagnetic interference. Use shielded cable when necessary, and properly ground the shielding layer.

2. Horizontal and vertical, neat and beautiful

The lines should be kept horizontal and vertical as far as possible to avoid disorder. Use trunking or cable ties to fix the wires so that they are arranged orderly.

3. Clear identification

Both ends of each conductor shall be labeled with clear wire number (such as digital number or color coding) to facilitate future maintenance and overhaul.

Step 4 leave a margin

The length of the conductor should be left with an appropriate margin, which is convenient for disassembly and replacement of components. Generally, 10%-15% of the length should be reserved.

5. Hierarchical zoning
　　Wiring in the control cabinet can be divided into functional areas, such as main circuit, control circuit, PLC module area and power distribution area, which is helpful for management and maintenance.

Third, the typical wiring steps

1. Install the trunking and bracket

Install vertical and horizontal trunking according to the plan to ensure smooth wiring path.

2. Laying the main power cord

Starting from the circuit breaker, connect it to contactors, frequency converters or other high-power equipment in turn, and pay attention to the use of appropriate wire diameters and terminals.

3. Layout control circuit

Including the wiring of relays, buttons, indicator lights, PLC, etc., pay attention to the isolation of signal lines and power lines.

4. Connect the terminal block

The wiring of all electrical devices should be transited through the terminal block, which is convenient for maintenance and replacement.

5. Grounding and shielding treatment

All metal casings and shielding layers shall be reliably grounded to ensure equipment safety and signal stability.

6. Finishing and marking

After the wiring is completed, fix the wires with tie straps, clean the trunking, and attach the wire number label.

Fourth, common problems and solutions

-Line cross-interference: Shielded cables should be used and channels should be routed separately.

-Frequent wiring errors: strengthen drawing review, do analog wiring or use wiring simulation software before wiring.

-Maintenance difficulties: strengthen logo management and keep the wiring neat and beautiful.

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The wiring of control cabinet is a crucial link in electrical engineering. Only by operating in strict accordance with the specifications and paying attention to detail management can the safe and stable operation of the control system be guaranteed. Through scientific and reasonable wiring design and construction, not only can work efficiency be improved, but also the later maintenance cost can be significantly reduced, which is a basic skill that every electrical engineer must master.