problems crimping with yellow crimps, 6mm.

[HappyHippyDad]

This is only the second time I have had to crimp 6mm cable. I remember the first time a couple of years ago I had problems. Again this time the connection just pulled apart in my hands.

After looking through the forum I can see that others have had the same problem specifically with yellow crimps. 1mm and 2.5mm seem to crimp perfectly well (again seen in other threads), but with 6mm there is a problem.

The reason for this thread is because other threads point to the crimp or the crimping tool being the problem. I have a CK crimping tool which has good reviews and crimps 1mm and 2.5mm very well (I have tested these in a vice), so I believed the crimp to be the problem. I was about to buy some SWA crimps as other threads point to these being good quality. However, my red and blue crimps were bought from the same manufacturer as the yellow so it didn't really make sense that it was the crimp at fault.

I've just been in the shed crimping 6mm in a number of different ways and think I have found the problem. With red and blue crimps you have the crimp flush with the crimping tool when you crimp. I assumed it would be the same with yellow, however the crimping tool is wider for the yellow crimps meaning that when you crimp you are crimping the entire half of the crimp (perhaps even slightly over), meaning that you are crimping down on the piece of metal that sticks out in the middle of the crimp and I think this must be stopping the crimping tool from crimping properly.

The top crimp (see picture) was crimped with the yellow crimp (outer part) flush with the crimping tool and just pulled out easily. With the other two I slightly pushed the crimp into the crimping tool so that the central piece of metal would not be disturbed (you can see that the bottom 2 crimps have a bit in the middle still raised whereas the top one doesn't). I could not pull either of these out when placed in a vice.

Correct crimping is so important I thought I'd mention my little test. I tested the 2 ways each with 5 crimps and it was the same with all of them.

 

[Aindowsimon]

Good shout ! I have the ck crimper and I do wot you have explained for a while , I reckon that maybe our crimper is designed for lugs in regard of keeping insulated cover flush to end of crimper

 

[joehat]

What's the max size cable yellow crimps do?

 

[Aindowsimon]

4-6mm as far as I know

 

[davesparks]

For 6mm it is better to use an uninsulated crimp with a hex crimper than those plastic jobbies.

 

[Simonslimline]

I just tried with my cembre crimpstars and it is totally solid. No getting it off.

 

[Aindowsimon]

I've seen butt crimps spoken about on this forum , quite a bit dearer but with adhesive lined heat shrink can see it being a superior crimp with it slightly translucent, wholesalers around me don't stick em

 

[Marvo]

Anything above 2.5mm I'd use an uninsulated ferrule or lug with an indent crimper or if it's a larger size like 16mm or above a hex type crimper then use heat shrink to finish. I'm not a big fan of insulated lugs TBH, they're not very consistent and they're not visually checkable in the same way an uninsulated crimp is.

 

[HappyHippyDad]

I just tried with my cembre crimpstars and it is totally solid. No getting it off.

I've just looked at that crimping tool Simon and there seem to be a few different varieties. Most seem to have the yellow part of the crimping tool flush with the red and blue, but the tipo HP3 has the yellow part sticking out just like the CK crimping tool.

 

[HappyHippyDad]

Anything above 2.5mm I'd use an uninsulated ferrule or lug with an indent crimper or if it's a larger size like 16mm or above a hex type crimper then use heat shrink to finish. I'm not a big fan of insulated lugs TBH, they're not very consistent and they're not visually checkable in the same way an uninsulated crimp is.

Do you mean this in relation to uninsulated butt crimps Marvo? I'm guessing you must mean the outside of the crimp is visually checkable rather than anything going on inside?

 

[HappyHippyDad]

For 6mm it is better to use an uninsulated crimp with a hex crimper than those plastic jobbies.

Anything above 2.5mm I'd use an uninsulated ferrule or lug with an indent crimper or if it's a larger size like 16mm or above a hex type crimper then use heat shrink to finish. I'm not a big fan of insulated lugs TBH, they're not very consistent and they're not visually checkable in the same way an uninsulated crimp is.

Why do you feel it is a better crimp when uninsulated (crimping tool is making direct contact with metal rather than PVC?)? Also, why a Hex crimping tool when the conductors get larger? Is this from experience or just known better practise?

 

[Simonslimline]

I've just looked at that crimping tool Simon and there seem to be a few different varieties. Most seem to have the yellow part of the crimping tool flush with the red and blue, but the tipo HP3 has the yellow part sticking out just like the CK crimping tool.

Yep thats the ones i have.

A silly question perhaps but which side are you putting the cable in to?

 

[davesparks]

Why do you feel it is a better crimp when uninsulated (crimping tool is making direct contact with metal rather than PVC?)? Also, why a Hex crimping tool when the conductors get larger? Is this from experience or just known better practise?

Because you can see when the conductor is properly inserted and can see that the crimp is properly located in the crimp die. Plus the standard uninsulated crimps have a thicker copper tube than the metal of the insulated.
I've stripped the insulation off of a few insulated crimps to have a look inside and they don't inspire confidence.

 

[HappyHippyDad]

Yep thats the ones i have.

A silly question perhaps but which side are you putting the cable in to?

View attachment 31875

The correct side

You should have been able to tell that Simon from the position of the indented number on the crimp

 

[Simonslimline]

The correct side

You should have been able to tell that Simon from the position of the indented number on the crimp

Just checking lol.

 

[HappyHippyDad]

Because you can see when the conductor is properly inserted and can see that the crimp is properly located in the crimp die. Plus the standard uninsulated crimps have a thicker copper tube than the metal of the insulated.
I've stripped the insulation off of a few insulated crimps to have a look inside and they don't inspire confidence.

How can you see? You cannot see inside so I'm guessing you mean where the conductor enters the crimp, but that would be the same as an insulated crimp? I'm talking in relation to butt crimps.

 

[Marvo]

I just think that compression crimping with the insulation in the crimper is just going to inherently give inconsistent results. I was taught as an apprentice that indent crimps were never to be used on MV terminations, only hex. I can't specifically remember why but they were considered more reliable. Also I have a small hand operated hydraulic hex crimper that has crimping dies going down to 16mm and up to 185mm so it's just easier for me to use it on any crimps in that size range, for 16mm and under I have a ratchet type indent crimper that is regularly calibrated, we pull-test lugs or ferrules as well and they pass with good results.

I think technology, materials and techniques have probably evolved somewhat since I was taught so I guess if they sell insulated crimps for 6mm then it should be okay to use them but with uninsulated lugs especially you can better visually check the result of crimping.

 

[davesparks]

How can you see? You cannot see inside so I'm guessing you mean where the conductor enters the crimp, but that would be the same as an insulated crimp? I'm talking in relation to butt crimps.

You can see by looking at it, you can see that all strands of the conductor have entered the tube and you can see that the conductor has gone all of the way in to the tube. Plus you can see that the crimp die is correctly positioned on the tube.
With an insulated crimp you cannot see the metal tube to know that the crimp die is correctly located, or see if there are any imperfections in the tube.

Plus, as you have noticed, the length of the insulating tube isn't quite standardised between manufacturers. So if you have crimps from the same manufacturer as your crimpers then you probably won't come across the issue you highlighted in your OP, however using crimps from another brand could be part of your issue.

With an uninsulated crimp and a hex crimper it is much simpler to do a test crimp and see if it is all ok before making the connection. Cutting through the test crimp to view the cross section of the crimped joint allows you to see if it has been made correctly or if there is a problem, a good crimp will compress the conductor fully, a bad crimp will leave gaps between the strands of the conductor.

 

[rich.250]

In my opinion those CK crimpers are a load of junk! My new one went in the bin and out came the old draper expert one I brought 12 years ago lol.
Never had a bad connection with that one.

 

[Andy78]

In my opinion those CK crimpers are a load of junk! My new one went in the bin and out came the old draper expert one I brought 12 years ago lol.
Never had a bad connection with that one.

I have to say that my daily ratchet crimp tool is CK and I have never had a problem with it. Still tight and makes a good compression every time. It is nearly 10 years old however and I do feel that CK tools in general were of a better quality some years back now. I had a set of CK drivers that lasted for years with daily abuse. I also had a newer batch that all shattered under normal use.

 

[Simonslimline]

I have to say that my daily ratchet crimp tool is CK and I have never had a problem with it. Still tight and makes a good compression every time. It is nearly 10 years old however and I do feel that CK tools in general were of a better quality some years back now. I had a set of CK drivers that lasted for years with daily abuse. I also had a newer batch that all shattered under normal use.

Seems to be the case with more than just tools these days unfortunately.

 

[Lucien Nunes]

I wouldn't be surprised that the first crimp is faulty due to the indentations being too near the centre. Part of the width of the counductor crimp zone is wasted on the endstop as you say, the remainder is on the very end of the conductors where the strands are likely to splay and escape, or even be forcibly ejected as the tube becomes funnel-shaped at the edge of the crimp zone. I would liken it to the very end of a conductor pinched halfway under a choc block screw.

I do also share concerns about the mechcanical durability of yellow crimps and the current rating of a completed joint relative to the size of conductor. I would only use products from a proper manufacturer with published performance and dimensional specifications and approvals. For critical applications as per Darkwood and Davesparks I prefer uninsulated crimps with a hex die - mechanically stronger, more consistent and reliably gas-tight crimp pattern and easier to inspect for successful installation.

 

[Skimpy Wan]

What do you recon to this as it seems reasonably priced (maybe too reasonably priced)...

http://pages.ebay.com/link/?nav=item.view&id=291059818578&alt=web

 

[telectrix]

i'vegot those same ratchet cutters. cost £60.brilliant.cut right through SWA inc. the steel armour. ( i done up to 16mm) . can't comment on the crimpers except seen then at elex and they looked a good piece of kit.

 

[Andy78]

What do you recon to this as it seems reasonably priced (maybe too reasonably priced)...

http://pages.ebay.com/link/?nav=item.view&id=291059818578&alt=web

These style of hydraulic crimper regularly pop up on eBay for about the £50 mark, but I have no idea of their reliability.
To put them in context though, I used to use a set of a very similar style and construction and they were spot on. A company I worked for bought them for a switch room job they had on at the time. The difference was that those ones cost £900 for the set.

 

[Skimpy Wan]

May give them a go then. The seller seems to indicate that they are ISO registered which means that their traceable items etc.
I need a new ratchet crimper for 10 - 16 mm crimps (which are £40 on their own) so not a bad offer if they work okay.

 

[Andy78]

May give them a go then. The seller seems to indicate that they are ISO registered which means that their traceable items etc.
I need a new ratchet crimper for 10 - 16 mm crimps (which are £40 on their own) so not a bad offer if they work okay.

If the largest you are doing will be be 16mm then a hydraulic set are a bit overkill. Why not get something a bit mechanically simpler. Less to go wrong with them then, especially being a budget product.

6-50mm² Electrician Cable Wire Crimping Crimper Hand Tool Pliers Ratchet Crimp | eBay

 

[Skimpy Wan]

I did see those, but thought they maybe a little too flimsy.

Mainly I just need 10 / 16 mm crimper as the bigger boy the boss has, so I get those when required (but handy to have my own for a later date).

 

[davesparks]

I have the same pattern hex crimpers as that, but from a reputable manufacturer rather than ebay

 

[Marvo]

The hydraulic crimper I have is by Hellerman Tyton, can't remember what it cost but I've had it a good few years and it's seen some action without any problems.

 

[shanky887614]

ive crimped loads with my cheap silverline and nno issues

 

[shanky887614]

If the largest you are doing will be be 16mm then a hydraulic set are a bit overkill. Why not get something a bit mechanically simpler. Less to go wrong with them then, especially being a budget product.

6-50mm² Electrician Cable Wire Crimping Crimper Hand Tool Pliers Ratchet Crimp | eBay

ive got them exact ones, here is a crimp cut open

 

[Skimpy Wan]

ive got them exact ones

Cheers dude. Were yours bought from flea bay as well? If so, can you let me know which seller you used and I'll see if I can get a pair from them as well (rather than using another seller / distributor where quality may differ?

 

[Skimpy Wan]

I have the same pattern hex crimpers as that, but from a reputable manufacturer rather than ebay

Out of interest, what make and how much are the pair you have Dave?

 

[Lucien Nunes]

here is a crimp cut open

Not sure about that pic, there seem to be voids between the strands and the tube. Makes me think the terminal was the wrong size for the cable or the die wrong for the crimp. Or is it not cut through the fully crimped section that was right inside the die?

 

[davesparks]

Out of interest, what make and how much are the pair you have Dave?

They are SWA, I bought them from the wholesaler years ago, I think they were around £50

 

[Marvo]

.....Makes me think the terminal was the wrong size for the cable or the die wrong for the crimp......

I think this is an inherent issue with the insulated crimps, the wire is rarely an interference fit into the crimp the way it is with an uninsulated type, hence the gaps. I think the insulated crimps try to cover several different wire applications like fine stranded, course stranded and even more than one wire CSA with the yellow ones which are rated for 4mm and 6mm in the same crimp. On the Maplin website it states 'The yellow types are suitable for cable from 2.5 to 6.5mm'........they're best left for work on cars and bikes in my opinion.

 

[davesparks]

To be honest these days I would be using wago connectors up to 6mm rather than crimps anyway, even in a car

 

[UKMeterman]

If you are using the bigger crimps say 2.5mm2 and up always remember I squared R is your enemy and so at higher currents say past 10 amps it is easy to show a mistake that causes a small increase in resistance will cause a big issue. For 6mm2 I would suggest remembering that the crimps and the crimping tool should be considered a matched set and come from the same manufacturer, this is in fact the rule at places like CERN who have had fires due to bad crimps and they have a lot of high current power supplies.

Crimp
34072 - TE CONNECTIVITY / AMP - CRIMP TERMINAL, BUTT, YELLOW | Farnell element14

Die
58423-1 - TE CONNECTIVITY / AMP - DIE, PIDG/PLASTIGRIP | Farnell element14

Tool
354940-1 - TE CONNECTIVITY / AMP - CRIMP TOOL FRAME, PRO-CRIMPER III,NO DIE | Farnell element14

 

[Skimpy Wan]

So rather than crimping to extend a circuit (I.e. 2.5 T&E) how would you recommend doing this - non-insulated / insulated crimps / solder (heat strink or not), connectors, wagon etc etc)?

 

[shanky887614]

So rather than crimping to extend a circuit (I.e. 2.5 T&E) how would you recommend doing this - non-insulated / insulated crimps / solder (heat strink or not), connectors, wagon etc etc)?

din rail terminals in adaptable box/ replace the cable, you can get wago's rated at 30amp which is plenty for 2.5 as the cable is rated at 27a before derating factors

 

[davesparks]

So rather than crimping to extend a circuit (I.e. 2.5 T&E) how would you recommend doing this - non-insulated / insulated crimps / solder (heat strink or not), connectors, wagon etc etc)?

These days I'd always use wagos, but when I was an apprentice it was always the good old 30A joint box.

You shouldn't use crimps with solid core cable unless the connector and the tool used are specifically intended for use with solid cores.

 

[telectrix]

i use ideal in line splice connectors up to and including 2.5mm. for solid cable extensions.

 

[Barry White]

i use ideal in line splice connectors up to and including 2.5mm. for solid cable extensions.

Not seen these will deffo give them a try . Won't use insulated crimps on solid cables and wago's are sometimes too bulky.

Cheers Tel

 

[telectrix]

these ones. look better as they are inline. not with both cables coming in from same side like wagos.

Ideal Spliceline? In-Line Push-In Wire Connector - Box 100 | eBay

 

[Marvo]

So rather than crimping to extend a circuit (I.e. 2.5 T&E) how would you recommend doing this - non-insulated / insulated crimps / solder (heat strink or not), connectors, wagon etc etc)?

We used to use solder regularly but in recent years we've had more and more written contract specs that specifically forbid it so we don't use it very often nowadays. Not sure why it's gone out of fashion....

 

[Lucien Nunes]

We used to use solder regularly but in recent years we've had more and more written contract specs that specifically forbid it so we don't use it very often nowadays. Not sure why it's gone out of fashion....

Perhaps because there are too many people who can't do it correctly, use the wrong solder, don't properly insulate afterwards etc. If you use a certified terminal according to the manufacturers' instructions, the result should be fairly predictable. Soldering depends directly on the skill of the wireman, which I have to say is sometimes noticeably lacking these days. Working on a lot of electronic stuff, rarely a day goes by where I don't solder a dozen or two connections; on extreme days I'll handle everything from 0.5mm pitch 64-pin connectors to 0.2 sq. ins lugs or upwards of 1000 connections. But when I want to extend a bunch of circuits I'll use Wagos or sealed splices, because on the whole they make sound joints and are quicker, soldering only where there is a definite advantage to do so.

 

[davesparks]

We used to use solder regularly but in recent years we've had more and more written contract specs that specifically forbid it so we don't use it very often nowadays. Not sure why it's gone out of fashion....

A general lack of skills is one reason I think.
The drive towards getting rid of lead from products can't have helped very much either, and whatever anyone says lead-free soft solder is just not the same.

 

[Barry White]

A general lack of skills is one reason I think.
The drive towards getting rid of lead from products can't have helped very much either, and whatever anyone says lead-free soft solder is just not the same.

It dont seem to flow right and I just dont get on with it still using the old stuff but not much left

 

[Lucien Nunes]

not much left

Thankfully 60/40 is likely to be available for decades yet as there are still applications where it is necessary and isn't prohibited. Plus it has to be used for repair of exisiting equipment as you can't rework with lead-free where 60/40 was used during manufacture. I use about equal amounts of both as I handle a lot of older stuff.