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7 Minutes to Understand Terminal Blocks
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7 Minutes to Understand Terminal Blocks

Views: 87     Author: Site Editor     Publish Time: 2020-05-29      Origin: Site

Terminal blocks, also sometimes called terminal connectors, are used to connect two or more wires together, and to provide an electrical ground for a circuit. They consist of a clamping component and a conducting strip.

While electronic circuits can process signals and produce outputs, they almost always need to be connected to external components, power sources, inputs, or outputs. Terminal blocks are available as rows, but each terminal connects to only a single wire. Terminal block connectors are very useful in situations that require semi-permanent connections, which may require inspections, wire replacement, repair, and change (this is why terminal blocks are incredibly common in domestic wiring and industrial environments). While not all terminal blocks have PCB contact pads or legs, they always have some mechanically solid body made of plastic or other insulating material.

terminal blocks and connectors

The types of terminal blocks

There are kinds of terminal blocks in the market and can be classified on the basis of structure, device type, termination options, etc. In this article, we will introduce four main categories: Pluggable Terminal Blocks, PCB Spring Terminal Blocks, PCB Screw Terminal Blocks, and Barrier Terminal Blocks.

Pluggable terminal block

A pluggable terminal block has a cable entry to allow the connection of a wire or cable, a plug output to allow for easy connection to a socket. This pluggable terminal block connector is very useful in situations in which hot-swapping may be important or a connection is expected to be removable for servicing or inspecting. Allowing you to connect a wire simply by inserting it. Most pluggable terminal blocks require the use of a ferrule. A ferrule strengthens the end of the wire/conductor. However, some pluggable terminal blocks allow to insert a solid conductor directly or a stranded conductor by inserting a screwdriver into the release hole.

PCB spring terminal blocks

PCB spring terminal blocks are using spring pressure to retain the wire clamped. Spring clamps are a newer alternative to screw clamps and are generally used for relatively small wires. It is a new type of terminal block with a spring device, which has been widely used in the world's electrical and electronic engineering industry: lighting, elevator lifting control, instruments, power supply, chemistry, and automobile power, etc.

PCB screw terminal blocks

PCB screw terminal blocks are those that have a screw as the method for holding a cable or wire. It is more common to see screws have flat-head fittings, and these types of terminals are often found in situations in which voltage and current demands will be moderate (domestic/commercial wiring). They are incredibly strong if done correctly and can be used in permanent scenarios. Screw clamp terminals are the most common type of connection method. The wire or conductor is simply pressed against the conductor strip in the block by tightening the screw. Screw terminals accommodate a very wide range of wire or conductor sizes.

Barrier terminal blocks

Barrier terminal blocks have a screw-down terminal with a standard product accepting a wire directly underneath the screw. Typically, they have more bottom side terminal options available in the same footprint and can accept different wire accessories on the top side of the terminal.

The barrier strip terminal block is very similar to the screw terminal connector in that they use screws as the mechanism to hold cables. Barrier terminal blocks often have more than one termination point for multiple cables and, because of this, have small barriers between individual terminals. Barrier strip connector can also have small lids and enclosures to further protect cabling and are commonly found in domestic wiring and other high-voltage scenarios that need to prevent arcing or potential short-circuits.

Main parts of terminal blocks

All the terminal blocks have the below mainly components:


Circuit path where wire engages and carries current through the housing. Typically made of a copper alloy. With an expansion coefficient that matches the designated wiring. This matching coefficient is important to prevent any loosening of the connection due to differing expansion rates. It also aids in reducing any corrosion that might be caused by the electrolytic action of two different metals.


Material that insulates conductive path from exterior and adjacent circuits. Generally made of flame retardant plastic 


The mechanism applies force or ensures the wire is connected to the terminal. It is made of various metal alloys.

The advantages of terminal blocks

Terminal blocks are designed for quick and simple connections that can be quickly done and quickly fixed. They are modular block with an insulated frame so that the block can be easily mounted on or unmounted, also allows us to increase the number of terminals according to the requirements. What’s more, the terminal block provides a safe route for a circuit to terminate, reducing the risk of short circuits within your system or serious injury to members of your team. Compared to other types of connectors, the terminal block is relatively cheap.

Terminal blocks tend to have high current and voltage ratings, and are much tougher than standard connectors. Because they are rugged and touch-safe, they are widely used in aerospace, rail transportation, shipbuilding, machinery, metallurgical chemical, power communication electrical control, and other fields.

application of terminal blocks

Sun is a professional terminal block manufacturers in China, providing high-quality pluggable terminal block, PCB spring terminal blocks, PCB screw terminal blocks, and barrier 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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