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.

 

[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