Views: 76 Author: Site Editor Publish Time: 2022-01-14 Origin: Site
A terminal block (also called a connection terminal or terminal connector) is a modular block with an insulated frame that secures two or more wires together. It consists of a clamping component and a conducting strip. A typical simplest terminal block is as shown in the image below.
There are various types of terminal blocks that can be used in a design. These are some of the most common:
PCB Mount
Often referred to as Eurostyle or wire-to-board terminal blocks, PCB mount terminal blocks work by inserting bare wires into the module where a clamp secures the wire in the housing. The housing is then soldered to a PCB in common footprints. PCB mount terminal blocks can be single, dual, or multi-level modules.
Barrier Strips
These terminal blocks have a screw-down terminal where a ring or spade terminal is attached to the wire and then inserted onto the screw and tightened into the housing. Barrier strips are commonly used where vibration is a concern.
Feed-Through
Feed-through terminal blocks are used to connect two wires together for wire-to-wire connections. This terminal block type has one input and one output contact where two distinct wires are fed into opposite sides of the housing. Like PCB mount versions, these can also be single, dual, or multi-level modules.
Pluggable terminals
Pluggable terminal blocks are those that have a cable entry to allow the connection of a wire or cable but a plug output to allow for easy connection to a socket. These types of terminal blocks are very useful in situations in which hot-swapping may be important or a connection is expected to be removable for servicing or inspecting. Screw contacts are the most common type of connection method for inserted cables, but the screw often has a small metal plate attached to the end, which allows for the gripping of both small and large cables.
Screw terminals
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). While wires bound to a terminal block are not physically bonded with the use of solder, they are incredibly strong if done correctly and can be used in permanent scenarios. Great care should be taken when tightening terminal blocks because over-tightening can damage the inserted cable and result in an unreliable and potentially dangerous connection.
The first step in selecting the right Terminal block is to choose the desired connection technology.
Stud / Bolt Type Terminal Blocks are generally preferred for connecting power cables. The wires are secured with Nut and Bolt arrangement inside these Terminal Blocks. Stud Type connections are used in applications subject to severe vibrations. In these types of connections, wires are crimped with Ring Type or Fork type Lugs/ferrules which are connected to the flat surface of the Current Bar inside the Terminal Block.
Spring Clamp Terminal Block has pre-stressed spring Clamps which are actuated by using a standard screwdriver for inserting the wire. The wire is directly held against the Current Bar by the pre-stressed Spring Clamp. These types of Terminal Blocks offer Gas tight connections and find their applications in typical wiring conditions with heavy vibrations like Lifts, Cranes, Elevators and Railways applications like connections inside Rail wagons, Bogie wiring and Signal Junction Box wiring. These are compact Terminal Blocks with unique design and facilitate ease of wiring
Push in Type Terminal Blocks are next-generation advanced design Terminal Blocks. Solid or Lugged wires are simply pushed into the connection points with minimum insertion force. No tools are required for carrying out this action. To release the wire from the terminal block, you can simply press the push button provided on the top of the terminal.
While it is possible to connect two wires together without a terminal block, connecting more than two can be challenging and dangerous. Once wires are stripped, the clamping element within the block keeps the lines securely in place, allowing the user to easily determine where everything needs to go. The insulated frame that houses the wires keeps the wires secure, and creates simple mounting for ongoing electrical projects.
Terminal blocks tend to have high current and voltage ratings and are much tougher than standard connectors. Because of their rugged, touch-safe design, blocks provide versatility and reliability that lends their use to a wide variety of uses and industries.
