PS, I must admit I used to solder some of my crimps as well. Until I figured out it didn’t add any value/ quality.
- Only consider crimp + solder in very specific cases (static/high-current/low-vibration setups), and even then it’s considered unnecessary or harmful.
This is the case!
As I said, only the tip is soldered
The cable is fixed in a non-vibrating environment (cabinet)
The cable is high-temperature certified ( IEC60228 Class 6)
If of course you are using cheap rigid battery cables with plastic insulation, you could not because it would melt.
Case closed.
(I’m a former installation & development engineer with over 40 years of experience, used to install microwave communications stations and afterwards developed inverter applications years ago… )
I think the main issue is that theres not a uniform 35mm², theres several different standards for lugs. An overview between two commonly used, at least in germany, standards can be found at Klauke. To note there is, that they identify the correct crimping die not by cable cross section, they do it by a code stamped into the lug, KL16 for example.
DIN compression cable lug or tubular cable lug | Klauke
Another issue is the cable diameter due to its stranding. A coarse stranded 35mm² has not the same outer diameter than a fine-stranded 35mm² has. You should not use the same lug for both, or you should not use a lug designed to be used for a fine-stranded cable on a coarse-stranded one (the other way round it might not even fit, so if youve ever asked yourself why the damn 35mm² lug does not fit onto the 35mm² cable without fraying, then this might be an explanation).
Ive been crimping lugs for almost two decades now, with various dies and tools, and yes it is a hassle selecting the correct one, reading the lug documentation just to press two things together. But its necessary. If the lug does not have a documentation, or at the very least a standard its been built according to, then dont use it.
The best tool to crimp that ive used so far was a four sided hydraulic crimper, with three moving jaws. from 16-240mm² everything was possible, with the same tool, and due to the hydraulic pressure relief valve, it crimped them all solid.
If i can choose, then im using compression cable lugs according to DIN46235, since they come with markings on the tube indicating where and how many times you need to crimp. They are also able to take coarse and fine stranded cables
No, I don’t argue against it for specific edge cases. But in general it is strongly advised against, as motivated above, that’s all.
I agree a good crimp starts with matching lug, cable and crimping die. Using standardized tools, materials and processes is the best way in a professional production environment but crimping isn’t that much of a rocket science that it can’t be done correctly by manual selection, using the information in this topic and some common sense.
Its definitely not rocket science. What i tried to say is, use brand cable lugs, that come with a documentation, then said docu will tell you how to properly crimp them. No guesswork necessary
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Just a little bit rocket science 
It is is still very common to do it wrong at first. And sometimes never improving upon that in some cases, kuch marine installers kuch. The key insight IMHO is that a good crimp results in a solid cold welded connection. And the need to use good heat shrink + glue for long term protection.
Well I did not think my query would have caused so much discussion clearly there is a lot more to the subject than I might have 1st thought. I checked if there was a data sheet on the lugs I bought and all I could find was a part code for each size. I found another outlet where I have an account and they sell the Cembre make. There is a form of data on the listing for the lugs which declares info as.
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· Annealed to guarantee optimum ductility
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· Insulation sleeve form to allow easy introduction of the conductor
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· Maximum Voltage Rating: 11kV
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· Operating Temperate Range -50°C to +150°C
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· Manufactured from electrolytic Copper tube with a purity greater than 99.9%
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· Electrolytically tin-plated to avoid oxidisation.
The ones I bought had nothing like that and had no manufacturers name other than Engex which is just a marketing packaging as lots of different items are sold under that brand.
I was interested in the discussion on soldering as I have a view from a different experience.
About 50 years ago I had an electric fan heater and noticed the plug had got very hot and when I looked at the connections they were loose. The wire ends had been solder tinned nowadays they would be ferruled. The pressure from the terminal screw and heat had softened the solder and resulted in poor contact. Another example was, I experienced problems with a particular brand of tungsten filament bulbs in the bayonet light fitting, in that as the bulb got hot the solder softened and the pins under spring pressure dented the solder on end of the bulb causing the bulb to lock in place. Changing brand solved that problem. I would not trust soldering anything that was likely to become hot and also under pressure so my inclination would be not to solder a crimped terminal.
Indeed as other have said, this Chinese imports do not have the correct sizes marked on the crimp dies, ignoring the size marking, I also doubt whether the dies are to specification at all, I have used the the dies with the best fit on the lug, but this is hit and miss and should not be the case, you have done the right thing by crimping a sample lug and checking it, the attraction of them for someone who is only to do a dozen crimps or so is the price, especially compared to a quality set of crimpers. I have also come across lugs that are marked with 2 sizes, such as 35 to 50mm, best to avoid those. Is you lug a tight fit on the conductors before crimping. Also of course of if installing on a boat a do not solder lugs as alternative.
Final tip: Use a small tyrep around the stripped wires to easy insertion into the lug. Or leave a small ring of insulation that can be shifted to the end of the wire and removed once all strands are inserted. And yes, no solder, unless there is an extraordinary, specific and tested engineering requirement to do so, I think that has been establisched by now. And take care not to cut the strands with a knife when stripping isolation, there a good simple tools to prevent just that.
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If your 35mm cable is of ‘ no name’ brand, most likely your 35mm cable isn’t exactly 35mm, maybe no more then 30mm.
Copper is now these days very expensive, selling 30mm copper for the price of 35mm is a very easy way to make more profit, as easy as printing your own dollars.. legally.
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It is actually important to cut through a test crimp to check them periodically as in installer. Any air gap means the crimper is not performing needs repair or replacement.
It is easy to spot as well with thermal or temp checks on lugs. They run hotter.
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Today I took delivery of some Cembre lugs. I took one of the make that gave me the problem and the equivalent Cembre size and did some measurements. (Lug 35 mm2 M8 hole)
Cembre Egnex
Weight 14g 9g
Outer dia mm 11.5 10-11 variable
Plate thickness mm 2.7 2.0
Plate width mm 7.2 5.5
Cost per gram weight pence 6.0 8.67
Per item the Cembre was 6p dearer but get 55% more lug.
I measured up the 50mm M8 lug as well and that was inferior to the Cembre.
Outer diameter 13 vs 10.5 thicknes 3.1 vs 2.8 plate width 9.0 vs 7.7. Weight was simiar at 18g but the Egnex was longer. Nevertheless down on the critical parameters
I will make up some new leads tomorrow as a proper test but I reckon I know what the result will be. Think I will be taking sample to the outlet that sells the Egnex. Been wasteful on cable but may be able to rescue the longer ones.
Thanks Julian for pointing me in the Cembre direction.
Oops lost the formatting but it is 2 columns Cembre then Egnex
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Glad to have been of help.
I use Klauke and Cembre. Pls mind not all variants fit into Lynx as they might interfere with the Mega-fuse.
For comparison Klauke SG, normal and Cimbre.
CN vs Klauke SG.
I crimp my 70qmm twice with manual hydraulic 16t press from CN.
That is a reallly good comparison thank you. It looks like a much better quality crimp than I can achieve.
I have been replacing the previous cabling and woried I might not have enough of the 35 mm left I sought to see if i could take the Egnex lugs off the 35 mm I had done. They came off dead easy with hardly any effort.
Very interesting everyone, thanks. I’ve used a Chinese hydraulic hex crimper on my 25, 35 and 70mm2 cables and lugs. Takes a bit of “technique” to get the best results because of the poor size accuracy of the dies. I always put a screwdriver through the hole in the lug at each end of the cable after crimping and pull as hard as possible. I’ve only had one come loose so far and re-crimped it. I also use a thermal imaging camera (topdon tc002c) which plugs into my iPhone which is pretty effective for monitoring temperature of cables and lugs. I will routinely check all the connections and cables to spot any hot spots hopefully before any big issues develop.
Maybe crimpt a second time on top of the First crimpt with rotated by one phase of the six flat areas.
Or take an inlet one size smaller.
Thanks yes. On the last couple of crimps and coming to the end of the job I did do that and it improved the crimp. The crimper is one with the rotating dies in the jaws and if you put the jaws together without a lug they meet up exact. But as you close the jaws together they move out of alignment due to the play in them within the jaws. I found by lifting one back into position as I closed the jaws it helped. There are too many variables to contend with I think a crimper sold by the manufacturer of the lugs would be a good start then the only variable will then be the cable.
I suspect the red 35 mm was under size.
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