Another set of crimp terminals and insulated wire splices

Last month I posted a review of crimp terminals for stranded wire. Today, I’m continuing the review on the same topic.
In this review, I’ll test two different sets: one contains various types of terminals, and the other contains insulated sleeves for joining wires.


As I mentioned last time, I bought a set with a coupon, so it worked out relatively cheap. This time I got two sets for review, as a supplement to the previous one, since I don’t need all of their contents, just some of it.

Set of insulated sleeves for joining stranded wire, price: $8.03 - link
Set of assorted terminals, price: $22.24- link. The price seemed to be quite a bit lower, but I can’t find it now.

The sets were packaged very simply: the box of terminals was wrapped in bubble wrap, while the sleeves came in a zip-lock bag.


I’ll start with the sleeves. I should say right away that I’m more of a fan of soldered connections covered with heat-shrink tubing. But that kind of connection is less suitable for production, and as far as I know, it’s no longer recommended—probably because it requires a higher level of skill to do properly.

The listing said the set included three types of sleeves—red, blue, and yellow—and specified a crimping range of 0.5-6.0mm2 or 10-22AWG.

I wouldn’t call myself a nitpicker, but remembering the previous set, I counted what arrived. It all adds up: 50 of each color. Then I transferred them into more convenient zip-lock bags, keeping a few of each color aside for testing.


Sure, you could say this set is overpriced, but the very first Google result for the product name showed me an absolutely astronomical price at a local store. When I worked out the cost of a set like this, it came to 555 UAH, or about $20, though it says it’s made in Italy. Even at ChipDip, I got a price of around $12, but in any case, I haven’t seen one for less than $11.


The sleeves have three different diameters, but are all the same length: 25mm. The insulation is very hard, almost like ordinary plastic. For some reason, I thought it would be a little softer. The material is presumably PVC.


While searching online for other places that sell similar sleeves, I came across a technical drawing with specifications. Interestingly, the sleeves differ not only in diameter but also in length.
For example, the Italian ones I showed above measured 21.5-23-27mm.
The lengths on this drawing are also different: 17-17-20mm. So I can say that they vary not only by where you buy them, but also in size. Until now, I thought they were standard.




The tube is non-magnetic and is advertised as copper, although for this kind of work I usually use tinned copper sleeves. But testing showed that it doesn't look much like copper.
1. The cut surface is white, like aluminum.
2. It's soft.
3. It won't take solder as-is, but after I scraped the surface with a knife, I was able to tin it with ordinary flux.




Before moving on to another test, I got curious about the color coding, so I looked it up online again and found that:
Red - 0.5-1.0 mm²
Blue - 1.5-2.5 mm²
Yellow - 4.0-6.0 mm²

The GSI-P, however, uses a slightly different size range:
Red - 0.25-1.5 mm²
Blue - 1.0-2.5 mm²
Yellow - 2.5-6.0 mm²

The second option is more convenient, since each size overlaps its neighbor to some extent. In my case, though, the sleeves most likely follow the first option.


For the experiment, I used three pairs of wires: about 0.5 and 1.0 mm², 2.5 and 2.5 mm², and 4 and 4 mm².


But I ran into a bit of a snag with the crimper. Last time, I complained that I couldn't figure out how the colors corresponded. The colors are the same—red, blue, and yellow—but they're arranged in a different order.


At first, I assumed the tool manufacturer had mixed up the markings, so I tried crimping a red sleeve with the smallest crimper die. That was a bad idea: I could barely squeeze it all the way, and had to press so hard on the handles that I was worried about damaging the tool itself.


It turned out to be much simpler. The crimper's color markings correspond to the colors of the terminals and sleeves, but they're offset. Let me explain.
There are three basic colors—red, blue, and yellow—but when there are more than three sizes, manufacturers may add more positions while keeping the same colors, arranged like this:
red, blue, yellow, red, blue, yellow.

I've highlighted my crimper's color sequence above to make it clear how the sizes correspond.


So, of the three basic sizes, the crimper only covers red and blue. It's too small for yellow, but can crimp sizes smaller than red, which are marked blue. The assumption is that the common blue terminal is so different from the smaller blue one that you can't possibly mistake them.

Below is a photo showing the common color-to-size correspondence.


But back to the experiment.
1, 2. When I tried crimping the red sleeve with the smallest die, I squeezed it so hard that the crimper's markings were clearly imprinted on it.
3. I crimped the second sleeve correctly, using the die with the red marking; it's the one at the bottom of the photo. I couldn't pull either wire out.
4. I tried crimping a blue sleeve with the same die (marked red), and again could barely squeeze it all the way.
5. When I put the blue sleeve in the die marked blue, things went much better, but because of my mistake, one wire wasn't clamped. While I was positioning the sleeve in the crimper, the wire shifted without me noticing and slipped out. So when I tried to pull it out, it came out easily.
6. The attempt with the yellow sleeve failed. First, I could barely get the sleeve itself into the die, and when I tried to squeeze it, I realized I'd be more likely to break the tool than crimp anything.


Experiment results:
It crimps 0.5 and 1.0 mm² wires perfectly.
It crimps 2.5 mm² wires perfectly, although I made a mistake and couldn't pull the clamped wire out.
I couldn't crimp 4.0 mm² wire because the crimper wasn't suitable.


The result of crimping with the correctly sized die.


Comparison of the correctly and incorrectly sized dies. At the top, I used a die that was smaller than necessary, which flattened the sleeve a little more. The main difference, though, was that it compressed the insulation too much.


The aftermath of the experiment :)


Naturally, I wasn't entirely happy with this state of affairs, so I decided to find out what the correct crimper is.
I found that I should use one that's similar to mine, but still a little different.
This crimper is called the BM534.


Or, for example, the CTK-01, which crimps with an oval profile.
The correct crimping process has two steps: first crimp one wire, then the other. At the same time, part of the sleeve's insulation collar is crimped too, so the wire doesn't wobble. The information was taken from here.
By the way, you can see in the photo that the die consists of two parts, with the largest one separated off, most likely because the sleeve itself is longer.


I tried crimping the sleeves in two stages, as shown above.


Since the wire connection can loosen over time and start to heat up, the insulating sleeve must be able to withstand this too, helping to prevent a fire.
Near the very beginning of the review, I included a screenshot showing Italian sleeves, which were listed as meeting the UL94-V0 flammability standard. I found a description of the test method for this standard and decided to try it myself.


I tried setting fire to each piece of leftover insulation with a lighter. Here’s what I found:
1. Burning rate — it barely burns.
2. Extinguishing time — about one second; the limit is 10 seconds.
3. Dripping — none.
4. Afterglow time — no afterglow, or very little; the limit is 30 seconds.

The plastic simply chars when exposed to flame and barely burns. It produces a small amount of smoke with a faint smell. After the flame is removed, the smell is gone within 10–15 seconds, including from the plastic itself. The only thing I noticed was that the hot plastic gets a little softer.

All in all, the result is pretty good, if not for one BIG BUT. And this “but” outweighs the minor quirks of the crimping process, the fact that the sleeves do crimp after all, and the fact that I’d have been perfectly happy with the blue and red ones without the yellow ones that my crimper can’t crimp.
The sleeve material. I’m increasingly inclined to think it’s either aluminum or an alloy with a high aluminum content. If so, these sleeves must not be used to crimp copper wires. Aluminum wires do exist, of course, as do special copper-aluminum sleeves, but nowadays they’re so rare that they’re practically nonexistent.



The second set is more like the previous one, but I ordered it mainly for two types of terminals.
It also comes in a plastic box, though this one is cheaper. The previous box had its top and bottom joined by hinges; this one is a single molded piece, so it probably won’t last very long.


As a bonus, there was a self-adhesive label inside the box listing the contents. It’s actually useful as a quick reference for matching terminal diameter and color to wire diameter.



Set specifications -
Manufacturer: Excellway®
Model: CT02
Material: PVC + pure copper
Type: 15 Value
Quantity: 2360 pcs
Box Size: 205x105x30mm

The full list of items, along with wire diameters and quantities. As you can see, the set includes the most commonly used sizes. I use 0.5 and 0.75 for low-voltage wiring; 1.0, 1.5, and 2.5 can be used to crimp household electrical wires.



And it would all be fine if it weren’t so depressing. The set includes 1700 uninsulated terminals, and during shipping they spilled all over the box. What a mess :(


Apparently this wasn’t the first time it had happened, since the ends of the dividers around these terminals had been covered with hot glue. The manufacturer probably tried to seal this area so the terminals wouldn’t spill out if the box got crushed during shipping. But one thing really escapes me: why didn’t the manufacturer simply put these terminals in small resealable bags? Then the buyer could just pour them into their compartments and be done with it. It’s an obvious and simple solution...


This time I didn’t count everything. I just counted the insulated terminals, since there aren’t many of them. Besides, I had to take them out anyway while sorting through the uninsulated ones.
The number of insulated terminals was roughly right: some sizes were short by one, others by two, and some were spot on.
As for the uninsulated ones, I took the easy way out and dumped them into one pile without sorting them by type. I just don’t have the patience to sort 1700 nearly identical-looking items into compartments :)


So, let’s assume the terminals had been sorted properly and take a look at what they’re like.
The set contained three types of terminals in five different sizes, for a total of 15 varieties.
1. Uninsulated
2. Insulated, in the same sizes
3. Double insulated, designed for two wires with the same cross-section as those in items 1 and 2.

I was most interested in the uninsulated ones, for small connections where the main thing is simply to crimp the wire, and in the double ones—in fact, I was even more interested in those. I got the rest more or less as a “bonus” thrown in with the previous set.





For a test, I picked wires with roughly matching cross-sections—0.5, 0.75, 1.0, 1.5, and 2.5 mm²—and one terminal of each type.


I used the standard die for crimping. I crimped the single terminals in the slot matching the cross-section marked on the die, and put the double terminals in the next larger slot, since their cross-section is twice as large.
For example, 2×1.5 mm² was crimped in the 2.5 mm² slot, and 2×2.5 mm² in the 4 mm² slot.


This is what the resulting “tails” looked like.


The crimps came out great. My only complaint was with the white terminal: I didn’t position it quite straight in the crimper, so it ended up crooked. I only noticed after squeezing the crimper handles.


The single terminals went smoothly. Honestly, I even enjoyed crimping the wires—it’s easy and the results are neat :)


That’s it for the tests. Let me try to sum things up.
First, the ferrule set.
They crimp well, and the plastic is flame-retardant. The red and blue sizes are very convenient for me; I suspect the yellow ones will just sit unused.
But I have a strong feeling that the ferrules themselves are made of aluminum. If that’s really the case, they’re completely unsuitable for use with copper wire.

The terminal set is simpler. They crimp well, hold the wire securely, and seem to be copper. The range of sizes is also well suited to household use. But I have a major complaint about the packaging: now the uninsulated terminals are basically all jumbled together. They may look different, but it’s still inconvenient.

I also learned a few things along the way:
a. Terminals, ferrules, caps, and similar items generally come in three sizes, identified by color: red, blue, and yellow. There may be other colors too; the review includes a chart.
b. When crimping, the color marking should match the color of the ferrule’s insulation. If the colors match but the sizes don’t, it’s best not to try it :)
c. My crimper can crimp only red and blue terminals. It has a yellow marking, but it belongs to a different size system.
d. It’s best to look for these items locally first, and buy a couple of each to check whether they’re copper.

That’s all from me. I hope this review was useful and helps you make the right choice.