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Terminal blocks are a fundamental part of modern electrical and electronic equipment, providing a reliable and practical way to connect, distribute and organise electrical wiring. From industrial control equipment and power supplies to building automation and PCB assemblies, the right terminal block can make a significant difference to the performance, reliability and serviceability of a finished product.
With so many designs available, choosing the right connection technology can sometimes be challenging. Screw, screwless, pluggable, PCB-mounted and surface-mount solutions all have their place, depending on the application.
What Are Terminal Blocks?
A terminal block is an electrical connection component designed to securely join wires or conductors while providing electrical insulation and mechanical protection.
Unlike permanent soldered connections, terminal blocks provide a structured connection point that can generally be installed, inspected, disconnected or replaced more easily. This makes them particularly useful in equipment where wiring needs to be organised or where future maintenance may be required.
Terminal blocks are available in numerous configurations, including screw-clamp, spring-clamp, push-in, pluggable and PCB-mounted designs. The most suitable option depends on factors such as available space, conductor size, current and voltage requirements, installation method and the environment in which the equipment will operate.
Hitaltech provides a broad selection of terminal block solutions, including PCB-mounted screw terminal blocks, screwless terminal blocks and other connecting technologies for industrial and electronic applications.
Understanding the Different Terminal Block Types
There is no single terminal block design that suits every application. Different connection technologies offer different advantages.
Screw Terminal Blocks
Screw terminal blocks use a screw-clamping mechanism to secure the conductor. They are one of the most established terminal block designs and remain popular because they provide a straightforward and secure connection.
PCB-mounted screw terminal blocks are particularly useful when wires need to connect directly to a printed circuit board. Hitaltech’s PCB-mounted screw terminal block range includes numerous series and configurations, with pitches ranging from 2.54 mm to 15 mm and current ratings extending from 2 A to 125 A, depending on the product. This broad selection allows designers to choose a terminal block based on their PCB layout, conductor size and electrical requirements.
Screwless Terminal Blocks
Screwless terminal blocks use spring or other tool-free clamping technologies rather than a conventional screw. This can simplify installation and help reduce assembly time.
For applications where fast wiring is important, screwless terminal blocks can provide an efficient alternative to traditional screw connections. Hitaltech’s HSTC range, for example, is available in several pitches and pole configurations, with high- and low-profile versions available.
Pluggable Terminal Blocks
Pluggable terminal blocks combine a fixed PCB connection with a removable plug. This allows the wiring harness or connected equipment to be disconnected without removing the terminal block from the PCB. This can be particularly useful for equipment that requires regular servicing, replacement or modular assembly.
Multi-Level Terminal Blocks
Multi-level terminal blocks incorporate multiple connection levels within a single component. By effectively stacking connection points vertically, they can help designers make better use of limited PCB or panel space.
For compact control equipment and densely populated assemblies, this approach can provide a useful space-saving solution.
PCB-Mounted Terminal Blocks
PCB-mounted terminal blocks are designed to be soldered directly to a printed circuit board, creating a convenient wire-to-board connection.
Hitaltech’s PCB-mounted range includes a substantial selection of screw terminal blocks, with different pitches, orientations, wire-entry arrangements and configurations available. The range is designed to support applications from low-level signal connections through to higher-current power connections.
Terminal Blocks
What Is a Surface Mount Terminal Block?
A surface mount terminal block is designed to be mounted directly onto the surface of a PCB using surface-mount technology (SMT), rather than relying on leads passing through drilled holes in the board.
Surface-mount technology can be particularly valuable when PCB space is limited or when manufacturers are using automated assembly processes. Eliminating through-holes can also provide designers with greater flexibility when routing tracks and arranging components.
It is important, however, to distinguish between a surface-mount terminal block and a conventional PCB-mounted terminal block. Not every PCB terminal block is an SMT component. Many PCB terminal blocks, including numerous products in Hitaltech’s range, use through-hole pins that are soldered through the PCB. The appropriate mounting technology therefore depends on the board design, assembly process, mechanical requirements and electrical specification.
Why Are Terminal Block Connectors Important?
Terminal block connectors provide more than just an electrical connection. They can contribute to the overall organisation, reliability and maintainability of an electrical system.
A well-selected terminal block can provide:
Secure conductor retention
Reliable electrical contact
Electrical insulation
Consistent wire positioning
Easier installation and maintenance
Improved wiring organisation
Flexible PCB or panel layouts
Simplified inspection and troubleshooting
For industrial equipment, where vibration, temperature changes and repeated servicing may be encountered, mechanical reliability is particularly important.
Hitaltech’s PCB-mounted screw terminal blocks use screw-clamp technology to provide secure wire retention, while product-specific specifications define factors such as conductor size, current rating, voltage rating and operating temperature.
Choosing the Right Terminal Block
Selecting terminal blocks should begin with the electrical and mechanical requirements of the application.
- Consider the Wire Size
The terminal block must be suitable for the conductor being used. Check the manufacturer’s specified solid and stranded wire ranges before selecting a product.
For example, Hitaltech’s MSG series supports different conductor sizes depending on the applicable standard, with solid wire capacity up to 2.5 mm² and stranded wire capacity up to 1.5 mm² in specified configurations.
- Check Current and Voltage Ratings
Current and voltage ratings are critical when selecting terminal blocks.
The required rating will depend on the application and applicable electrical standards. Designers should always refer to the specific product datasheet rather than relying on a general rating for an entire product family.
Hitaltech’s PCB-mounted range covers a broad range of electrical requirements, making it possible to select products for both lower-power electronic circuits and higher-current applications.
- Select the Correct Pitch
Pitch is the distance between adjacent terminal positions.
Common PCB terminal block pitches include 2.54 mm, 3.5 mm, 5.0 mm, 5.08 mm, 7.5 mm and 7.62 mm, with larger pitches also available.
The correct pitch will depend on PCB space, required electrical clearance, conductor size and the desired density of connections.
- Consider the Mounting Orientation
Terminal blocks can be available in horizontal, vertical and other orientations.
The orientation can have a major effect on the finished product, particularly when space around the PCB is restricted or when wires need to exit the enclosure in a particular direction.
Hitaltech’s PCB terminal block range includes different housing orientations and designs, giving engineers flexibility when optimising the board layout and wiring arrangement.
- Think About the Operating Environment
Temperature, vibration, humidity and chemical exposure can all influence terminal block selection.
Materials used for the housing and conductive components need to be appropriate for the intended environment. Hitaltech products use robust insulating materials and conductive metal components, with individual datasheets providing detailed operating-temperature and material information.
Terminal Blocks for PCB Applications
PCB terminal blocks are widely used where a PCB needs to interface with external wiring.
Typical applications include:
Industrial control systems
Automation equipment
Building management systems
HVAC equipment
Power supplies
Energy and power equipment
Instrumentation
Control panels
Electronic equipment
Consumer and commercial products
The combination of a PCB and terminal block provides a practical interface between the electronics on the board and external wiring.
Hitaltech’s PCB-mounted screw terminal block portfolio includes numerous series, including MSB, MSM, MSD, MSG, MSQ, MTB, MSS, MTS, MSP, PSB, PSM, PSQ and the HRT range.
Terminal Blocks and Space-Constrained Designs
As electronic equipment becomes smaller, connection density becomes increasingly important. Designers may need to accommodate more connections without significantly increasing PCB dimensions. This is where features such as narrow pitches, multi-level designs and different terminal orientations can become particularly valuable.
A high-density terminal block solution can help maximise the available PCB area while still providing accessible and organised connections. The choice should always balance compactness with the required electrical clearance, conductor size, current capacity and ease of installation.
Why Choose Hitaltech Terminal Blocks?
Hitaltech has supplied connecting technologies since 1986 and offers a broad portfolio of terminal blocks, connectors, PCB interconnect products and enclosures.
The company’s terminal block range is designed to give engineers flexibility when specifying connections for different applications. Rather than relying on a single connection technology, Hitaltech offers screw, screwless, PCB-mounted and pluggable solutions. This allows the terminal block to be selected around the requirements of the application rather than forcing the application to fit a particular connector design.
Hitaltech can also support customers beyond component supply through its Value Added Services. These services include custom development, cable and wiring assembly, component kitting, printing and other production-focused solutions designed to simplify manufacturing and reduce production complexity.
Finding the Right Terminal Block for Your Application
Choosing the right terminal block requires more than simply selecting a component that fits the PCB. Wire size, current, voltage, pitch, mounting method, orientation, operating temperature, available space and applicable standards should all be considered before making a final selection.
Whether you require a conventional PCB screw terminal block, a screwless connection, a pluggable solution or a surface mount terminal block for an SMT assembly process, understanding the available terminal block types is the first step towards making the right choice.
With a comprehensive portfolio of terminal blocks and terminal block connectors, Hitaltech can help engineers identify a connection solution suited to their PCB, wiring and application requirements. Looking for the right terminal block for your next project? Explore Hitaltech’s terminal block range or contact our technical team for assistance with product selection.
For more information on Everything You Need to Know About Terminal Blocks talk to Hitaltech UK Ltd