Ferrules for Low Voltage Applications
A ferrule is a metal tube crimped over stranded wire to secure the strands within a screw terminal. Electric wire ferrules are also called electric end terminals, or bootlace connectors/ ferrules.
Why am I such a fan?
- They’re useful
- They’re inexpensive
- They are very cool
It’s very European. Call me old fashion but I think European stuff is neat. I think people would be well served by looking into how people do things in other countries and consider adopting them. Take the best of both worlds. Take the metric system for example, we should adopt it immediately. (Opinions expressed in this article are my own and are reflective of Lock Alchemy’s opinions). It’s my new personal mission to get people to use these. #ferrulegang will be showing up on Instagram very soon.
It’s a fairly straightforward solution to be pretty obvious problem. Copper cable strands get mashed under terminals, get cut and sometimes a loose strand can cause a fault. Connect, disconnect, reconnect – you have a mess on your hands. Ferrules allow you to remove the wire from the terminal block and easily move to another location on your board or in your control box without have to deal with flattened or damaged wire.
These are very common in automotive wiring and wiring PLCs (Programmable Logic Controller). In automotive their used to create a more secure connection that’s resistant to vibrations. In PLCs, they’re used for all the above reasons and for the ability to easily change wiring. Often times their required by PLC manufactures.
Weidmuller has a lot of technical data available available about the benefits of ferrules for creating good electrical connections. I’m not posting any links because they might change where they store this information.
I don’t see a huge downside to using ferrule connectors. They’re is the cost of the crimping tool(s) and the ferrules themselves. Past that it’s time.
Actually crimping them is very easy. Learning how to buy ferrules is more difficult. Firstly, they’re in Metric, like everything else should be. (Getting that I like the metric system yet?) There is a color coding system for the gauge of wire used in a ferrule. Sounds really smart and easy right? Sort of. There’s a German system and a French system. I’m really not sure what’s used where and what’s preferred in different European countries. I’d love to hear feedback on this.
Great – German system and a French system. The colors are based on metric wire sizes. So your AWG (American Wire Gauge) cables aren’t going to fit into that system without doing some math. Sure you can order European ferrules online. After shipping they get kind of expensive. Enter Ferrules Direct. They have tons of, you guessed it, ferrules. They sell ferrules in standard packs of 500 and mini packs of 100.
The French color for the equivalent of 22 AWG is Pink in the French system and Turquoise in the German convention. I don’t know about you but I’d prefer not to use those colors. Ferrules Direct has a W, D, and T series that only vary in colors. So you can get 22 AWG ferrules in white, orange, pink, turquoise, or yellow. So you can select a color based on personal preference or brand colors. I chose white and some orange ones because it’s like of Lock Alchemy’s color. Along with width for wire size another specification for ordering ferrules is barrel length.
UL & Legal Stuff
I’m not a lawyer, I’m not giving you advice, I’m not responsible for anything you do. Use UL rated connectors. They’re some discussion about matching a brand of crimper with brand of ferrule. Do your own research. It’s your customer, your company, and your name on your work – be proud of it.
I like using good tools that work well and will hold up. It’s not easy looking for crimpers for a few reasons: they’re expensive, they’re hard to find, the technical information is a little confusing. I did a bit of research about crimpers before I made my selection. Some people on Facebook groups swear by cheap crimpers available on Amazon. Knipex, Weidmuller, and Mullex all make premium crimpers ($200+). I’m sure there are other brands available. If I’m missing something send me an email.
Hexagonal or Sqaure
In general, square crimps for square blocks and hexagonal for round blocks. I’ve actually used the opposite crimp on some terminal blocks because they were very tight and the other crimp style fit in better. I’d recommend cutting off the old ferrule, re-stripping the wire, and crimping on a new ferrule as opposed to just recrimping the same ferrule.
Square crimp for square blocks
Hexagonal for round blocks
I got a cheap set of ferrule crimpers to justify myself why I bought premium ones. They came with some presumably non UL listed ferrules. They actually are pretty decent. Of course I wouldn’t use these in the field but they’re good for testing and playing around with different sizes. That way you don’t have buy 100 packs of “real” ferrules of various sizes for your tests.
The crimpers work pretty well. The ratcheting function is not as smooth as premium crimpers. The odd thing about these is that they put a strange strain on your hand. The end of the crimp is a little difficult. For 10 or so crimps it would be fine. If you have 100 to do, I’d consider getting a real crimper.
These are the crimpers I went with. The Weidmuller PZ SQR and PZ HEX. I got a screaming deal on them. A lot of people on Facebook forums like the Knipex one. I’m assuming they went with them because they’re already familiar with the Knipex brand and quality. I saw a few people mention that they like the Weidmuller better than the Knipex ones.
These are amazing. They feel great in the hand. Ratchet very easily and put very little strain on the hand. The end of the crimp is butter smooth. 10/10.
Here are two 18 AWG wires with single wire ferrules I crimped on. Less than 1 cent for both and 10 seconds of time – a lifetime of connection :)
I plan on updating this article with pictures from panels and boards.
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