With so many shapes, sizes and variations, how do you choose the PCB terminal block that’s right for your application? In this Hitaltech guide, we’ll be delving into all the essential need-to-know information on how to choose the best terminal blocks for you and how to use terminal blocks.
How to select a PCB terminal block
The number of PCB terminal blocks on the market is vast and almost overwhelming at times, so it’s easy to see why some people may have issues with choosing the right one. If this sounds like you, then we’ve got all the information you need.
Below, we’ve listed all of the most important factors to consider when it comes to choosing the best terminal blocks for your application. You’ll also find some advice on how to use terminal blocks once you’ve made your decision.
Connection Method
Plug and socket-type terminal blocks offer the benefits of quick installation and removal and help reduce the risk of miswiring during installation and servicing. Fixed PCB-mounted terminal blocks don’t offer such benefits but are typically lower-cost options.
Screw terminal blocks are widely used in numerous field wiring applications and accept a wide range of stranded and solid conductors. Screwless terminal blocks may be a better option in high-vibration applications or where the speed of wiring is an important factor.
Wire Entry Size
Usually given in mm2 or AWG (American wire gauge), wire entry size is determined by amperage ratings, the type of conductor being used (i.e. solid or stranded) and the range of conductor sizes that may be used during field wiring. You might also consider using ferrules on the end of conductors during factory wiring processes.
Number of Poles
Do you need one-wire entry (single pole) or multiple? You can pack as many as 25 poles into a single terminal block (and more in modular units), with single and multi-row configurations supporting your design ambitions.
Pitch
Consider the required voltage ratings of your application, creepage and clearance constraints against the relevant approval criteria. The pitch of the terminal block also affects its physical size, which can be a challenge for design engineers to balance size constraints with approval standards.
Geometry
The geometry of a terminal block will influence the angle of wire entry to the PCB. As the terminal block is often the first component used by a consumer, you’ll also want to consider geometry in relation to appearance, durability, usability and reliability.
Assembly Process
The latest generation of STH terminal blocks has changed the game in terms of automated assembly, but if you want to take advantage of them you’ll need terminal blocks made from high-temperature plastics and have them supplied on tape and reel for automatic placement and reflow soldering.
Customisation
Despite the variety of off-the-shelf options, terminal block customisation remains vitally important, especially at the early stages of the design process. Once you’ve settled on your required connection method, the number of poles etc, further customisation options can include colours, markings, pitch variations and geometric variations.
How to use terminal blocks
To use terminal blocks, strip the wire insulation and insert the stripped wire end into the appropriate terminal. If you’re using screw terminal blocks, tighten the screw. If using screwless terminal blocks, engage the clamping mechanism to secure the wire.
Verify the connection by gently tugging the wire and using a multimeter to check the current. Then, repeat for any additional wires while ensuring each is properly identified. Insulate the connections using the provided covers or accessories, then you’ll be all good to go with your set-up terminal blocks.
Contact us
If you need any more assistance on how to choose the best PCB terminal blocks for your application, contact us today on +44 (0)1253 899910 or e-mail uksales@hitaltech.co.uk. A member of our friendly team will get back to you as soon as possible.
