Wire ferrules and crimp terminals

David_AVD

David_AVD

Grandpa Elf
Community project designer
Generous elf
Joined
Jun 12, 2010
Messages
4,699
Location
Victoria Point (Brisbane)
Wire ferrules (also called boot lace terminals) and crimp terminals are not something that has been talked about a lot on ACL.

First we'll look at ferrules. They are great for wires that are going into terminal blocks on controllers, fuse boards, etc. You can get them in various sizes to suit the cables being used. Always choose the ferrule size so that the stripped wire is a fairly snug fit into the ferrule tube. Unlike quick crimp terminals, the colour of the sleeve has no bearing on the tube size.
full


Here's an example of them used on a fuse PCB. No chance of stray wires shorting things out.

full


You will need to buy a ferrule crimping tool, but they are only around $25 on eBay. For blinky use, I'd recommend the 4-sided type (shown below), not the 6-sided type.

full
 
Fork type "QC" (quick connect) crimp terminals are ideally suited for wiring up power supplies. The colour of the sleeve denotes the wire size they are suitable for.

full


Here's them being used on a power supply.

full


It's important to use the correct size for the cable, otherwise the wire will be loose and possibly be intermittent or lead to heating / melting. Not good!

See below for an example of what not to do. Those crimps are way to big for most of the wires.

full


Again, you'll need a crimp tool. Get a ratcheting one like this, not a $5 special.

full
 
Ferrules really are the "go to" option for terminating wires. The metal crimp section prevents the wires from shorting to anything adjacent and the plastic backing section forms a kind of strain or fatigue relief. It prevents the wire from pivoting on the part that gets clamped up which is typically where metal fatigue failures will occur.

Tinned (soldered) wires kind of have the same effect as ferrules but are in fact a pretty terrible termination option. The point at which the solder ends and untinned wire starts is the point at which metal fatigue failures occur. The tinned section is quite rigid so it doesn't flex but the point at which solder ends does. This means that any movement in the wire will typically happen over that 1mm or less section of cable. In addition to being a point of failure due to metal fatigue a tinned joint is subject to plastic deformation over time. This means that a terminal that was done up tight may. over time, become loose as the solder gradually conforms to the pressure being exerted on it. In addition to this if a joint becomes hot due to either under-rated cable size, excess current or poor contact pressure (which can be caused by aforementioned deformation) then the solder in the tinned joint can soften which causes a bit of thermal runaway where the joint gets hotter and hotter until failure.

Short story is. Use ferrules and crimp terminals where you can. They're not very expensive and they can save you from a number of problems.
 
Totally agree about the Ferrules. They save stray strands of wires causing shorts
I browsed E-Bay for them and came across a site that had the same size Ferrule in different colours.
The mixed quantities vary from time to time but you can get purchases like these - you just need to keep and eye on the wire size as most of it is in AWG and not in mm2 and you will need to cross reference between the two depending on what you are used to.
All my Dumb RGB Pigtails use colour coded Ferrules. AC power also done with them.
The double wire one are good too, but sometimes you need to watch the size terminals they're going into.
I used Full ring crimp terminals on my PSU 240 volt terminals - only because that i what I had at the time. They are a pain if you need to remove the wires later. I would definitely go the quick connect U shaped ones from here in.
 
videoman3857 said:
I used Full ring crimp terminals on my PSU 240 volt terminals - only because that i what I had at the time. They are a pain if you need to remove the wires later. I would definitely go the quick connect U shaped ones from here in.
Click to expand...

Ditto on the full ring terminals. I use them primarily in case the screw loosens a bit, the wire wont come loose and blow something up. But, yes, they are a pain to take out and the screw almost always falls out somewhere hard to reach!
 
Wires soldered as Alan has mentioned is also an illegal termination in the electrical industry for all the reason Alan has mentioned. So just another reason not to solder the ends then terminate. But Im sure everyone gets Low Voltage connections done by a licensed sparky and only does the ELV themselves.

Using the right screwdriver is important as well for making the termination tight. You should always after tightening them give them a gentle pull to make sure they are not loose.
 
videoman3857 said:
Totally agree about the Ferrules. They save stray strands of wires causing shorts
I browsed E-Bay for them and came across a site that had the same size Ferrule in different colours.
The mixed quantities vary from time to time but you can get purchases like these - you just need to keep and eye on the wire size as most of it is in AWG and not in mm2 and you will need to cross reference between the two depending on what you are used to.
All my Dumb RGB Pigtails use colour coded Ferrules. AC power also done with them.
The double wire one are good too, but sometimes you need to watch the size terminals they're going into.
I used Full ring crimp terminals on my PSU 240 volt terminals - only because that i what I had at the time. They are a pain if you need to remove the wires later. I would definitely go the quick connect U shaped ones from here in.
Click to expand...
The link is a fail :(
I've tended to stick with the 1 size for 1 colour rather than try to colour co-ordinate the ferrules. This immediately lets me look at a ferrule and know the current capacity of the cable.
 
AAH said:
The link is a fail :(
I've tended to stick with the 1 size for 1 colour rather than try to colour co-ordinate the ferrules. This immediately lets me look at a ferrule and know the current capacity of the cable.
Click to expand...
The first link failed and I updated it- try again.
Yes, Allan, I too generally use the one colour for the one size cable - that tends to be the norm in the electrical industry.
I chose to use R.G.B. and black for my Dumb RGB pigtails as the cables are not RGB and I was getting them mixed up puttiing them into the terminal block with just white bootlaces..

Benslights said:
i use ferruls all the time now they are the best.

https://www.ebay.com.au/itm/Paron-JX-D4-4-In-1-Ratchet-Terminal-Wire-Crimper-Crimping-Pliers-Tool-26-10-AWG/361977728893?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

is what i got and you can change the teeth for other crimps
Click to expand...


Nice - a crimper with mixed dentures :laugh:


Rickras85 said:
But Im sure everyone gets Low Voltage connections done by a licensed sparky and only does the ELV themselves.
Click to expand...

No licence needed for ELV - Extra Low voltage - 35 volts and below.
For those who think 240 volt is high voltage - wrong- it's actually designated low voltage
A sparky is a must for safety. Also if an unlicensed person does a LV wire up and it causes a fire and the inisurance company finds out..... no insurance.
Save up all your 240 volt jobs and get them done at once. The circuits should be tested and the earth resistance confirmed - all needing specialised equipment which the average joe blow does not have.

Kimbo3000 said:
Ditto on the full ring terminals. I use them primarily in case the screw loosens a bit, the wire wont come loose and blow something up. But, yes, they are a pain to take out and the screw almost always falls out somewhere hard to reach!
Click to expand...
Magnetic tip srewdriver works wonders.
 
Last edited by a moderator:
In some ways I'd prefer a fork terminal coming away from the connection than a ring terminal flapping about arcing. It's all down to the likely dangers I guess.
 
videoman3857 said:
No licence needed for ELV - Extra Low voltage - 35 volts and below.
For those who think 240 volt is high voltage - wrong- it's actually designated low voltage
A sparky is a must for safety. Also if an unlicensed person does a LV wire up and it causes a fire and the inisurance company finds out..... no insurance.
Save up all your 240 volt jobs and get them done at once. The circuits should be tested and the earth resistance confirmed - all needing specialised equipment which the average joe blow does not have.


Magnetic tip srewdriver works wonders.
Click to expand...

Was seeing if people would think 240V is HV. To let people not that are aware of AS3000 ELV is below 50V AC and 120V DC ripple free. 240V is L.V which is where a sparky is needed . Luckily for me i have the christmas bug but also have the magic licence to allow me to do all my terminations legally and rate all my cables properly.

As i design and build control panels for a living i actually dont use ferrules as i found too many people would not crimp the ferrule properly causing the extra point of failure verse a spring loaded terminal with a twisted wire inserted straight in, after twisting 100's of 1000's of wires you get pretty good at putting the wires in so stray wires aren't poking out.
 
I'm not aware of any spring loaded terminals in the blinky world. They are either screw terminal blocks with a wire protect leaf or a rising clamp arrangement. Fork terminals are nice for the type of screw terminals on power supplies as the screw washer/plate clamps down evenly on both sides.

Personally I'd use the ferrule over bare twisted wires any day. As long as the ferrule is not grossly oversized for the wire, they seem to provide a reliable connection. Like any type of crimping, it needs to be done properly. If you can pull the ferrule off the end of the wire, it either wasn't crimped fully or the ferrule is too large for the wire.
 
You must log in or register to reply here.
Back
Top