Installation Specification for Terminal Blocks: Ensure Stable Operation of Electrical Systems
Terminal blocks are key components for achieving reliable wire connections in electrical systems, and their installation quality directly affects the stability and safety of system operation. The following elaborates on the regulatory requirements from four aspects: layout, installation, protection, and maintenance:
1、 Layout specification: Avoid crossing and evenly distribute
Do not cross: Adjacent wiring terminals should maintain sufficient spacing to avoid wire crossing and short circuits caused by touching. For example, in power terminal blocks, current terminals and voltage terminals should be arranged in separate zones to prevent accidents caused by misoperation.
Uniform distribution: The terminals on the circuit board or terminal block should be evenly spaced to avoid local overheating or mechanical stress concentration. For high-density wiring scenarios, double-layer terminal blocks can be used to improve operational convenience through staggered design (with a distance of 2.5mm between the upper and lower layers).
Stay away from interference sources: Input/output terminals and strong/weak current terminals should be arranged separately and isolated with empty terminals or insulated partitions. For example, clear markings should be placed between the control circuit and the power circuit terminals to prevent signal interference.
2、 Installation specifications: Secure and reliable, highly compliant
Torque control: Use a torque screwdriver to tighten the screws according to the specifications (recommended torque for M3 screws is 0.8-1.2N · m) to avoid poor contact or thread damage caused by excessive looseness.
Height limit: The installation height of the terminal should be as low as possible, and the distance between the component body and the lead wire from the board surface should not exceed 5mm to enhance the anti vibration ability and prevent dropping or contact.
Wire matching: The terminal specifications should match the wire cross-section, and it is forbidden to "match small terminals with large wires". For example, 10mm ² wires should use terminals with a rated current of ≥ 60A to prevent overheating and burning.
3、 Protection standards: adapt to the environment, strengthen insulation
Moisture resistant design: Moisture resistant terminals (such as IP65 protection level) should be used in humid environments, and conductive paste should be applied to the surface of the terminals to reduce the increase in contact resistance caused by oxidation.
Insulation strengthening: Terminal boards with circuit voltages exceeding 380V should be marked in red and equipped with insulation sheaths to prevent accidental contact. A reinforced insulation partition should be installed between the strong/weak current terminals, with a withstand voltage value not less than twice the maximum voltage of the system.
Environmental isolation: Waterproof terminal boxes should be selected for outdoor installation to prevent rainwater from entering; Heat dissipation space should be reserved in high-temperature environments to prevent accelerated aging of terminals.
4、 Maintenance standard: Regular inspection and timely replacement
Appearance inspection: Check the terminal box quarterly for cracks, deformation, and aging of the sealing strip. If any problems are found, replace them immediately.
Temperature rise test: Use an infrared thermometer to monitor the temperature rise of the terminals, which should normally be below the ambient temperature by+30 ℃. If the temperature rise is abnormal, it is necessary to tighten the terminals or investigate the problem of load overload.
Identification management: Each wire should be labeled with a wire number or function for easy maintenance in the future. For example, in the motor control circuit, the U/V/W phase lines should be marked with yellow/green/red to prevent misconnection.
