Flexible Wires Question - Page 1
Forum section: electronics / general

author: Balaur
author_rank: Unknown
timestamp: October 21, 2011, 10:06:36 am
content: 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/135380The 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 ashttp://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

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 21, 2011, 11:55:19 am
content: They do make this in smaller sizes for test leads etc. Try looking for ' test lead wire '

author: IanB
author_rank: Super Contributor
timestamp: October 21, 2011, 04:57:07 pm
content: Quote from: Balaur on October 21, 2011, 10:06:36 amThe 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.

author: Rufus
author_rank: Super Contributor
timestamp: October 21, 2011, 05:18:22 pm
content: Quote from: IanB on October 21, 2011, 04:57:07 pmNo 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.

author: KJ6EAD
author_rank: Contributor
timestamp: October 21, 2011, 07:33:05 pm
content: These are the ones I know of:http://www.daburn.com/2671UltraFlexibleSub-MiniatureWire-U/LSTYLE15681692.aspxhttp://www.daburn.com/2722PlasticKinklessTestLeadWire-5000V.aspx

author: Jimmy
author_rank: Regular Contributor
timestamp: October 21, 2011, 09:18:51 pm
content: 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

author: IanB
author_rank: Super Contributor
timestamp: October 21, 2011, 10:50:15 pm
content: 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 doneverytightly. 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.

author: Unknown
author_rank: Unknown
timestamp: October 21, 2011, 11:54:06 pm
content: 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.

author: Rufus
author_rank: Super Contributor
timestamp: October 22, 2011, 12:31:24 am
content: Quote from: IanB on October 21, 2011, 10:50:15 pmThe 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 herehttp://www.etco.com/electrical-connectors-reference/crimp-photo-gallery/.

author: sonicj
author_rank: Frequent Contributor
timestamp: October 22, 2011, 04:26:54 pm
content: i've made some nice wet noodle clip leads and adapters from turnigy silicon wire.linka nice jst crimp guide:

author: PetrosA
author_rank: Frequent Contributor
timestamp: October 23, 2011, 02:00:14 pm
content: 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 thicknessWire diameter (overall)Number of strandsEach 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.aspThis 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

author: SgtRock
author_rank: Unknown
timestamp: October 23, 2011, 03:07:59 pm
content: 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 FordBest RegardsClear Ether

author: Balaur
author_rank: Unknown
timestamp: October 24, 2011, 12:43:32 pm
content: Dear all, thank you for your replies.Quote from: mikeselectricstuff on October 21, 2011, 11:55:19 amYep, there are some eBay sellers offering this, it could be a very good source.Quote from: Rufus on October 21, 2011, 05:18:22 pmIndeed, the very fine strands are very quick to split if mechanically stressed. Sharp edges are a real killer for those.Quote from: KJ6EAD on October 21, 2011, 07:33:05 pmNice, indeed. It looks way more expensive than the equivalent Farnell offering. However, you have way more options to configure.Quote from: sonicj on October 22, 2011, 04:26:54 pmHey, that's interesting. Especially since some other useful stuff could be found in the store. Thank you!Quote from: PetrosA on October 23, 2011, 02:00:14 pmGood stuff. Many thanks!Quote from: SgtRock on October 23, 2011, 03:07:59 pmI 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, etcCheers,Dan

author: sonicj
author_rank: Frequent Contributor
timestamp: October 24, 2011, 09:41:56 pm
content: Quote from: Balaur on October 24, 2011, 12:43:32 pmSome re-assembly required.

author: maia
author_rank: Newbie
timestamp: November 10, 2011, 01:46:08 pm
content: This is a very good question and I appreciate all the answers, because they help me a lotIf 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.

author: robrenz
author_rank: Super Contributor
timestamp: November 10, 2011, 02:38:38 pm
content: 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 ElectronicsWire, Test Lead; 18 AWG; 10 kVDC; 20 A; Insulation: Red Silicone; 50 ft.; 0.144 Dia.Allied Electronics #885-0098 $19.799Pomona ElectronicsWire, Test Lead; 18 AWG; 10 kVDC; 20 A; Insulation: Black Silicone; 50 ft.; 0.144 Dia.Allied Electronics # 885-0097 6733-0 $19.800

author: Balaur
author_rank: Unknown
timestamp: November 10, 2011, 02:56:46 pm
content: 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 purposesand kept the rest for the lab. Bastard!I'll have a look at the Pomona ones instead.Cheers.