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How to Use Terminal Blocks and Connectors
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How to Use Terminal Blocks and Connectors

Views: 814     Author: Site Editor     Publish Time: 2020-06-23      Origin: Site

Terminal blocks are used to facilitate the connection of wires. In fact, they are a piece of metal sheet sealed in insulating plastic. There are holes at both ends to insert wires and screws to fasten or loosen them. For example, two wires sometimes need to be connected and sometimes need to be disconnected. At this time, they can be connected with terminals and can be disconnected at any time without having to connect them. It's very convenient and fast to weld or wind together.            

Terminal blocks are suitable for a large number of wire interconnection. In the power industry, there are special terminal blocks, which are single-layer, double-layer, current, voltage, common, breakable, etc. A certain crimping area is to ensure reliable contact and enough current.

You do need to use them right though and follow some ground rules when it comes to choosing and using the terminal blocks. The difference between blocks can lead to problems if an incorrect type is used or if it is not connected properly. Follow the advice below so you never have to worry about encountering these issues.

The steps of use terminal blocks and connectors

1. Terminal block type

Look at the electrical equipment you are working on to see what type of connection it requires. Normally you will have either a screw-in or plug-in connection.

2. Choose terminal block

Once you know the type of connection that is required, you need to find a terminal block that fits the rest of your requirements. Consider what space you have for the connection and how many wires need to be connected. Terminal blocks are supplied in a variety of shapes and sizes, so you should be able to find one that suits your needs.

3. Secure screw-in connection. 

Always make sure that any electrical equipment is turned off before beginning work. For a screw-in connection, you will need to strip a small amount of the insulation from the end of the wire. Normally, around 1/2 inch is sufficient but this will depend on the component. Unscrew the retaining screw from the terminal block then insert the wire into the hole. Tighten the screw into place. Make sure that it is fully tightened because if the wire is left loose, it will begin to heat up and melt the insulation. Over time, this could result in a fire so take a little extra time to make sure that it is secure.

4. Secure plug-in connection

Position the terminal block and run the electrical wires to it, connecting the male terminal to the female port. Press firmly to ensure that the connection is secure and won't come loose in the event of any subsequent movement.

5. Test equipment. 

Once you have made all the connections to the terminal block, test your equipment to make sure it works correctly. Afterward, check the terminal block and the connections to make sure that there is no excessive heat build-up and that the wires are still securely in place.

Here is a simple diagram

Materials to be prepared include terminal blocks, screwdrivers, wires.

1. First, strip the insulation of the wire 6-8mm.


2. Then, insert the exposed wire into the inside of the terminal block.


3. Then,  tighten the top screw with a screwdriver.


4. Pull it by hand to make sure it doesn't fall.


7-point requirements for wire and terminal connection


1. The wire head of multiple cores shall be tightened one step in advance and then connected with the terminal block.            

2. For the terminal to be distinguished from the phase, the phase sequence of the conductor shall be distinguished before connection.            

3. The oxide layer of small section aluminum conductor and aluminum terminal shall be clear before connection.            

4. When the large section aluminum conductor is connected with the copper terminal, the copper-aluminum transition joint shall be used.            

5. The proper distance shall be kept between the insulation layer of the conductor and the terminal block. 

6. When the flexible conductor is connected with the terminal, it is not allowed to have loose, broken, and exposed strands of thin wire core.            

7. The wire head and terminal must be connected in a flat, firm, and reliable way, and the contact resistance shall be minimized.


As famous China terminal block connector manufacturers, Sun provides professional electrical terminal block information and high-quality terminal blocks and connectors. If you have any needs, please contact us.




Sun Electric Co., Ltd
Founded in 2011, Sun Electric Co., Ltd specializes in the production of terminal blocks and industrial electrical connection products.

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