What are the requirements for terminals in distribution cabinet wiring?

Wiring of power distribution cabinet has the following requirements for terminals:

basic requirement

No damage and firm fixation: the terminal strip should be undamaged, and the installation and fixation must be firm, so as to ensure that the terminal will not loosen or fall off due to vibration and other reasons during the operation of the power distribution cabinet.

Good insulation: the insulation performance of the terminal should be good, which can withstand the working voltage of the circuit and prevent leakage, short circuit and other faults. For the circuit voltage exceeding 400V, the terminal board should have sufficient insulation performance and be painted with a red sign.

Identification and numbering

Serial number: the terminal should have serial number, which is convenient for finding and identifying, and convenient for installation, maintenance and maintenance personnel to quickly locate the required terminal.

Clear name and purpose: the number, name, purpose and operating position of each electrical appliance and terminal strip shall be marked, and the marked handwriting shall be clear and neat, and it is not easy to decolor and open the glue.

Layout requirements

Separation of strong and weak current: the strong and weak current terminals should be arranged separately with obvious signs, and empty terminals can be set apart or insulation-strengthening partitions can be set to prevent strong current from interfering with weak current signals.

Power supply terminal spacing: between positive and negative power supplies and between the positive power supply which is often charged and the closing or tripping circuit, an empty terminal should be used to avoid short circuit or misoperation of the power supply.

Special terminal setting: the current circuit should pass through the test terminal, and other circuits that need to be disconnected should pass through the special terminal or test terminal, and the test terminal should be in good contact, which is convenient for current measurement and circuit maintenance.

Adaptability requirement

Matching with conductor cross-section: the terminal should match the conductor cross-section, and the appropriate terminal should be selected according to the conductor cross-section area, so as to avoid the situation that small terminals are matched with large-section conductors and ensure the reliability and electrical performance of the connection.

Material matching: all connectors should be made of copper products to ensure good conductivity and corrosion resistance; Insulators should be made of self-extinguishing flame retardant materials, such as terminal V0 made of PA66, which is completely qualified in flame retardant grade, so as to improve the safety of the power distribution cabinet.

Wiring specification

Number of wires: One wire should be connected on each side of each terminal, and no more than two wires should be connected. For plug-in terminals, two wires with different sections shall not be connected to the same terminal; For bolted terminals, when two wires are connected, a flat gasket should be added in the middle.

Firm connection: The connection between wires and terminals should be firm and reliable. Whether bolt connection, plug connection, welding or crimping are used, the connection should be tight to prevent problems such as looseness and virtual connection, so as to avoid heating, sparking or even disconnection.