Terminal blocks are made of an insulated, modular housing designed to connect two or more wires together. They provide for secure, organized wire connections that allow for easy field inspection or repair.
Terminal blocks come in multiple types and wiring methods. They can be single feed-through for simple wire-to-wire connections, dual level consisting of two levels of connections stacked on top of each other, or triple level featuring three levels of stacked connections.
There are key factors to consider when selecting terminal blocks. This article will provide an overview of types of terminal blocks and the considerations to select a terminal block for your project.
Types of Terminal Blocks
There are different types of terminal blocks, each designed to meet different needs, such as compact circuit board connections to industrial power distribution.
No matter what your application requires, terminal block types like PCB mounts, barrier strips, and DIN rails can ensure secure, efficient, and reliable wiring solutions.
Here is an overview of the common types.
1. PCB Mount
PCB mount-type terminal blocks are mounted onto printed circuit boards. They allow for secure, organized connection of wires to the PCB. These are simple to mount and offer great space savings on the board. A PCB mount also allows for easy inspection and repair as they are easily swapped out.
2. Barrier Strips
Barrier strips use screw terminals where ring or spade connectors are attached to the wires and then inserted onto the screw and then tightened, thus securing the connection. Each wire sits in its own terminal, separated from neighboring terminals by a plastic insulating barrier. These terminal blocks work well for higher current and voltage applications.
3. DIN Rail
DIN rails are designed to be mounted on standard DIN rails in industrial panels or enclosures. DIN rail terminal block connection types can be screw-in, push-in, or spring clamp. These are ideal for industrial power distribution equipment and control panel wiring.
Wiring Methods
When it comes to creating secure and efficient electrical connections, choosing the right wiring method is essential.
There are three common wiring methods: screw, push button, and push-in.
Screw Terminal
These terminal blocks secure the wire to the terminal block conductor by tightening a screw to clamp the wire in place. These work well with stranded and single-core wires and, as previously noted, are often used in conjunction with ring or spade connectors on barrier strips.
Push Button
A push button opens a spring-loaded clamp that secures the wire. These are quick and easy to use and work well with single-core wires.
Push-In
These work similarly to push button style terminal blocks using a spring-loaded clamp to secure the wire. In this case, the wire is simply pushed into the terminal. These are also quick and easy to use and work well with single-core wires. Push-in terminal blocks are effective for harsh industrial environments.
Terminal Block Selection Considerations
When designing or maintaining electrical systems, selecting the appropriate terminal block is a critical step to ensure safety, reliability, and efficiency.
From current and voltage ratings to wire size and entry orientation, each consideration plays a crucial role in meeting the demands of your system while adhering to safety standards.
In this section, we’ll explore the most important selection considerations to guide your decision.
1. Current Rating
This is likely the most important factor to consider when choosing a terminal block. Too high of current can cause overheating and damage to the terminal block.
This poses serious safety concerns. A good rule of thumb is to choose a terminal block rated for at least 150% of the maximum expected current in the systems.
2. Voltage Rating
Voltage rating: Similar to selecting a terminal block to rated over max current, choose one that has a higher voltage rating than the system voltage. Voltage surges should be accounted for as well.
3. Pole count
Pole count is the number of individual circuits in the terminal block.
4. Pitch
Pitch is the distance between the center of one pole and the center of the next pole.
5. Wire size and type
Voltage and current ratings determine the minimum and maximum wire sizes the terminal block can accept. Ensure the wire used will fit the terminal block. The type of wire needs to be considered as well. Screw terminals work with stranded or single-core wires, while single-core works well with push-button and push-in styles.
6. Wire entry orientation
Terminal blocks have three common orientations: horizontal, vertical, and 45°. Select the orientation that best works within your overall design for ease of wiring.
Terminal Blocks Available at MISUMU
Terminal blocks offer easy and organized wiring connections. Following some basic design considerations, they provide an efficient method for connecting complex electrical system wiring.
Explore MISUMI’s catalog of terminal blocks for a wide range of applications.
