Specification Requirements For Terminal Blocks: The Entire Process From Design To Use
As the core component of electrical connections, the specification requirements of terminal blocks run through the entire process of design, selection, installation, acceptance, and maintenance, directly related to the safety and stable operation of electrical systems.
The design phase needs to follow a dual standard of electrical performance and mechanical strength. The contact resistance should be controlled within 0.8 ohms, using highly conductive materials such as copper alloy, and matching the cross-sectional area of the conductor according to the load current. For example, UT/OT series terminals are used for wires below 10mm ², and DT series terminals are used for wires above 10mm ² to ensure the rated current carrying capacity. Mechanical design should meet the requirements of moderate insertion and extraction force and stable retention force. For example, the vertical insertion depth of spring type terminals should be precisely controlled to avoid poor contact.
The selection stage needs to refine parameters based on the application scenario. In terms of environmental adaptability, PA66 material with a temperature resistance of 120 ℃ or above should be selected for high temperature scenarios, and IP67 protection level should be used for humid environments. The safety regulations require the terminal housing to have a flame retardant rating of V-0 and be equipped with anti misplacement design, such as keyway or color coding. For example, industrial control equipment needs to use European style terminals that support multi angle access from 90 ° to 270 °, while smart homes prioritize tool free installation of spring-loaded terminals.
Strict adherence to construction standards is required during the installation phase. The stripping length of the wire should be precise to 5-8mm to ensure that the copper core is not damaged; The torque of the screw type terminal should be controlled between 0.6-0.8N · m to avoid cracking or loosening of the plastic shell caused by over tightening, resulting in poor contact. The installation environment should be kept away from moisture and corrosive substances. Waterproof and moisture-proof terminals should be used in high humidity areas such as kitchens and bathrooms. For example, three-phase circuit terminals must be installed with corresponding phase markings to prevent misconnection and short circuits.
A long-term mechanism needs to be established during the acceptance and maintenance phase. During acceptance, it is necessary to test the insulation resistance, withstand voltage performance, and conductivity of the terminals, with a deviation not exceeding 5% of the theoretical value. A patrol schedule should be established for operation and maintenance, with screws tightened every three months in dusty areas and anti-corrosion terminals replaced annually in humid areas. For example, production equipment with a daily operating frequency of over a thousand times needs to switch to industrial grade high stress terminals and undergo infrared thermal imaging testing every three hours to ensure that the terminal temperature is within a safe range.
