Flexible Wires Question

[Balaur]

Hello all,

I've recently came across a spool of TPE  (Thermoplastic Elastomers) wire at work and I really like the texture of the jacket and the extra flexibility of the wire. This is the particular item: http://uk.farnell.com/mc-multi-contact/60-7200-22/wire-tpe-red-2-5mm-25m/dp/135380

The flexibility is likely given by the very fine strands, but the TPE jacket should also account for something. However, this wire is too thick for my needs (2.5 sq. mm / AWG13), way too difficult to solder correctly and debatable whether a crimp connector is effective (the very fine strands seems to wither away when looking at them).

I'm looking to buy for myself something similar but in smaller diameter such as http://uk.farnell.com/mc-multi-contact/60-7180-22/wire-tpe-red-0-5mm-25m/dp/135264. One potential application is test leads and such.

Do you have other suggestions for super flexible and nice to touch cables? Preferably on eBay or similar, so I could order for myself?

Thank you,
Dan

[mikeselectricstuff]

They do make this in smaller sizes for test leads etc. Try looking for ' test lead wire '

[IanB]

debatable whether a crimp connector is effective (the very fine strands seems to wither away when looking at them)

The way I've seen crimping done is to fold the stranded ends back over the insulation and then crimp both metal strands and insulation together. I presume this is the correct way to make a crimped connection as it provides both mechanical strength and electrical contact, but I have not read anything that specifically teaches how to use a crimping tool.

[Rufus]

The way I've seen crimping done is to fold the stranded ends back over the insulation and then crimp both metal strands and insulation together. I presume this is the correct way to make a crimped connection as it provides both mechanical strength and electrical contact, but I have not read anything that specifically teaches how to use a crimping tool.

No that would be absolutely horrendous.

The forces involved in crimping deform the wire strands and crimp body to effectively form a single piece of metal. That provides a robust and gas tight connection between strands and crimp (it is hard to even call this single piece of metal a connection any more). You certainly don't want insulation or anything else mixed in with the metal.

If there is a weakness where the strands enter the crimp it needs additional strain relief.

[KJ6EAD]

These are the ones I know of:

http://www.daburn.com/2671UltraFlexibleSub-MiniatureWire-U/LSTYLE15681692.aspx

http://www.daburn.com/2722PlasticKinklessTestLeadWire-5000V.aspx

[Jimmy]

Don't fold the wires back over insulation as the joint will creep over time and become loose as it pushed the insulation out. Just strip the wire and use a bootlace and crimper to terminate.

http://www.larpro.com.au/larpro/category/169

[IanB]

These are interesting comments about not folding the wires back over the insulation. The examples I have where this has been done are fairly narrow gauge test leads with alligator clips. The crimping in these cases has been done very tightly. There is no possibility of the wire coming loose. But equally this form of joining might just be an example of cheaply made test leads.

[alm]

Many of those cheap clip leads appear very poorly made and have very thin wires with just a few strands. They often have a few ohms of resistance. Not the place I'd look for proper crimps.

[Rufus]

These are interesting comments about not folding the wires back over the insulation. The examples I have where this has been done are fairly narrow gauge test leads with alligator clips. The crimping in these cases has been done very tightly. There is no possibility of the wire coming loose. But equally this form of joining might just be an example of cheaply made test leads.

The OP didn't say what he was considering crimping. My comments were about real crimped connections. All the cheap leads and cables with croc clips I have seen were soldered the crimp being around the insulation for strain relief.

Some sections through a good and bad crimps here http://www.etco.com/electrical-connectors-reference/crimp-photo-gallery/.

[sonicj]

i've made some nice wet noodle clip leads and adapters from turnigy silicon wire. link

a nice jst crimp guide:

[PetrosA]

I don't crimp small wires like that, but I've read a good amount of literature on the subject and have never seen anything about folding wires back around the insulation. Crimp connectors are supposed to be matched to the wire being used which is done by:

Outside insulation thickness
Wire diameter (overall)
Number of strands

Each crimp connector has a data sheet giving all these specs and more.

This link takes you to the Molex literature site. Go to the Tooling Applications section where you'll find some really excellent pdf crimping guides.

http://www.kelmscottpurls.com/molex/pdfonly.asp

This is the main handbook in case you have problems with the other link:

http://rhu004.sma-promail.com/SQLImages/kelmscott/Molex/PDF_Images/63800-0029_64016-0065.pdf

[SgtRock]

Greetings EEVBees:

I buy the cheap alligator test leads, then I take them apart and solder them. I even put a couple of layers shrink tube around the connection to give it a little more heft and grip. Some of the leads I have bought have had copper alligator clips. I solder a couple of these into a Pomona dual banana jack which I plug into my Fluke 87s and my capacitance meter to make testing caps and resistors easier and more accurate.

"Business is never so healthy as when, like a chicken, it must do a certain amount of scratching around for what it gets." Henry Ford

Best Regards
Clear Ether

[Balaur]

Dear all, thank you for your replies.

They do make this in smaller sizes for test leads etc. Try looking for ' test lead wire '

Yep, there are some eBay sellers offering this, it could be a very good source.

If there is a weakness where the strands enter the crimp it needs additional strain relief.

Indeed, the very fine strands are very quick to split if mechanically stressed. Sharp edges are a real killer for those.

These are the ones I know of:
http://www.daburn.com/2671UltraFlexibleSub-MiniatureWire-U/LSTYLE15681692.aspx
http://www.daburn.com/2722PlasticKinklessTestLeadWire-5000V.aspx

Nice, indeed. It looks way more expensive than the equivalent Farnell offering. However, you have way more options to configure.

i've made some nice wet noodle clip leads and adapters from turnigy silicon wire. link

Hey, that's interesting. Especially since some other useful stuff could be found in the store. Thank you!

http://rhu004.sma-promail.com/SQLImages/kelmscott/Molex/PDF_Images/63800-0029_64016-0065.pdf

Good stuff. Many thanks!

I buy the cheap alligator test leads, then I take them apart and solder them. I even put a couple of layers shrink tube around the connection to give it a little more heft and grip.

I like to the fact that I'm able to order very cheap stuff from China (while my local store wants to sell me the same stuff for 10x the price). Also, I'm very happy that I can actually afford and find things that I only dreamed about when I was young and enthusiast.

However, one of the drawbacks is that sometimes you have to check and fix some of the stuff you buy. The alligator cables or test leads are very good examples. I have found many with insufficient soldering or crimping, very cheap wires, broken springs, etc

Cheers,
Dan

[sonicj]

However, one of the drawbacks is that sometimes you have to check and fix some of the stuff you buy. The alligator cables or test leads are very good examples. I have found many with insufficient soldering or crimping, very cheap wires, broken springs, etc

Some re-assembly required.

[maia]

This is a very good question and I appreciate all the answers, because they help me a lot If you can suggest even more shops this would be good. I try to get more cheap stuff to be honest. I know that this could become a quality problem, but since I just started with electronics I'm not sure how much I should invest at first.

[robrenz]

Super flexible high quality lead wire. As nice as any I have encountered.  I know this is not necessarily cheap but this is the smallest packaging/price I have found for top quality wire.

 Pomona Electronics
Wire, Test Lead; 18 AWG; 10 kVDC; 20 A; Insulation: Red Silicone; 50 ft.; 0.144 Dia.
 Allied Electronics #885-0098  $19.799

Pomona Electronics
Wire, Test Lead; 18 AWG; 10 kVDC; 20 A; Insulation: Black Silicone; 50 ft.; 0.144 Dia.
  Allied Electronics # 885-0097 6733-0   $19.800

[Balaur]

Hey Robrenz,

Thank you for the recommendations. I think I'll order this for myself the next time.

In the mean time, I've managed to convince the local friendly technician to slip on a Farnell order the two 0.5mm wire spools.

Good quality, nice and flexible! So nice in fact, that the technician only gave me a few meters (for evaluation purposes and kept the rest for the lab. Bastard!

I'll have a look at the Pomona ones instead.
Cheers.