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How to Choose Terminal Blocks
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How to Choose Terminal Blocks

Views: 96     Author: Site Editor     Publish Time: 2020-06-09      Origin: Site

The terminal block is a kind of accessory product used to realize the electrical connection. It is divided into the connector category in the industry. With the higher degree of industrial automation and the more strict and precise requirements of industrial control, the amount of terminal is increasing. With the development of the electronic industry, more and more terminals are used, and more and more types are used.

Terminal blocks are widely used and essential in electrical connection, there are various terminal blocks in the market that are dazzling. Therefore, it is important to choose the right type of connector for your application. The aspects of terminal blocks that need to be considered are typically type, current requirements, voltage requirements, the wire being used, mechanical strength, and the environment.

electrical terminal block


Determine what type is required for your designated system, e.g. screw-mounted or screw-less, single feed-through or multi-level, fuse holder, ground circuit, direct mount or disconnect, and so on. There are pluggable terminal blocks, PCB spring terminal blocks, PCB screw terminal blocks, and barrier terminal blocks in the market.

Wire being used

For different terminal blocks, their size and wiring range are different. Generally, when using terminals, it is better to choose a slightly larger wiring range than the actual wire diameter. Not all wires are equal, and each wire type has its own advantages and disadvantages. For example, when choosing a terminal block for a cable, be sure to know the size of the cable (can it physically fit into the terminal block?) as well as if it’s single-core or multi-core. Multi-core wire does very well in screw terminals, whereas single-core wire does well in push-fit connectors.


Current requirements are arguably the most important aspect to consider because pushing too much current through a terminal block can result in overheating and, therefore, the destruction of the terminal block. Different models have specific current specifications, and the product must meet or exceed this standard. It’s better the chosen block can, in fact, handle the current that you expect to use plus 50 percent more. For example, if an expected current of 2A is to be drawn from a block, then a terminal block with a current rating of 3A would be sufficient.


Voltage also needs to be considered. The voltage causes problems with dielectric breakdown such that a voltage too high for a terminal block could cause current leakage between adjacent terminal blocks. However, high voltage requirements are often rare in design, which is why voltage considerations are typically ignored for voltages under 100 V. However, it is still important that this figure is checked before a terminal block is chosen!

Environment and Mechanical strength

The environment is also important when choosing terminal blocks. Some terminal blocks may be mechanically strong and able to handle high currents, but if the connection is being used in a naval environment, then the salty air could be detrimental to the metal contacts. The environment could also have wide temperate swings or contain mechanical vibrations, which make screw terminations unreliable.

electrical terminal connectors

Using space

Different terminals can be selected for different space sizes. For example, in a narrow space, double-layer or three-layer terminals can be selected; for a space with a flexible installation position, integrated terminals can be selected, etc.

Color of the terminal block


For the color, if there is no requirement for appearance, you can choose the color of the terminal arbitrarily. If the terminal is to be installed in the front of the equipment, it will affect the beauty of the equipment, then you can choose the color of the terminal according to the color of the equipment.

Appearance factor

In general, as the current increases, the wires become thicker, and the torque required to fasten these thick wires to the terminals also needs to increase. As a result, the power terminals require larger screws and a stronger insulating enclosure. Sometimes small screws are used to save space. This is often the case in very compact terminal products. Some wires are more than 1 / 4 inch in diameter, so these small screws are hard to handle. When technicians and maintainers need to install more than one wire, it can save time greatly to use large enough screws to simplify the wiring work



In recent years, with the sustainable development of society, the research and development of terminal blocks are moving towards the direction of high performance, diversification, greener, and more beautiful. Green is mainly reflected in the material of the terminal, including the environmental protection of the material, the fire resistance of the insulating material, the conductivity of the conductive parts, and the anti-biological erosion ability.

Terminal blocks are used in many designs and choosing the right one is very important. Learning to recognize the different types of connectors and their advantages and disadvantages can save designers time and money by understanding what their product is, what it will experience, and in what environment it will be used. As famous terminal block manufacturers in China, Sun provides professional electrical terminal block information and high-quality electrical terminal blocks. 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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