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I have a simple 22 AWG wire that needs to connect to multiple elements. Every connection is a solder joint. I would rather not cut up small wires, as it's for a batch run.

Normally I'd love to use daisy chained wire harnesses (google it) to connect some elements to a same wire, but this will not work in this application.

Is there a standard way to remove a bit of insulation from the middle of a wire?

toolic
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lode
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    Don't strip the wire. Use an insulation piercing wire tap. (google it). https://www.mcmaster.com/insulation-displacement-connectors/ – user57037 Jun 09 '22 at 03:29

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There is no need to actually remove some insulation - just cut the insulation all around the wire, then slide it apart at the cut. The insulation will compress a bit, and slide along the wire, leaving a bit of wire exposed.

Peter Bennett
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  • at 22awg, it can be hard to cut the plastic w/o the metal, and it's thin enough to be unforgiving. heat makes it easier to cut/tear, stretch, and smoosh the jacket and will lessen the time/care required whilst improving the success rate. – dandavis Jun 09 '22 at 03:16
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    @dandavis It is a lot easier with solid than stranded wire and if you're going to be putting solder blobs along the wire you lose most of the advantages of stranded anyways. Might as well go solid and make things a bit easier. – DKNguyen Jun 09 '22 at 03:26
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For small wire like that you probably just want to use an insulation piercing wire tap. For example, 3M 06129 Scotchlok 905 IDC Tap Connector.

enter image description here

(Original Picture URL: https://multimedia.3m.com/mws/media/507919M/3mtm-scotchloktm-instant-auto-electric-connector-905.jpg)

For larger diameter wires, there are actually insulation cutting tools that can flay the insulation and allow you to remove it from the middle of a wire.

enter image description here

(Images copied from here: https://jonard.com/cst-tools-round-cable-strippers)

user57037
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  • A big advantage of scotchlok taps over solder joints in the middle of wire is that your insulation problem is already solved. Tapping into existing wiring means you can't just thread on heatshrink, although on a new assembly that's not such a problem – Chris H Jun 09 '22 at 12:49
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    For anything that's precious, please, remove the reference to the Scotch Lock. :-)) It's the single most unreliable connection mankind ever invented. – Gábor Jun 09 '22 at 14:36
  • @Gábor impossible to inspect, wide variability, a million knockoffs with poorer quality or dimensional variances, whats not to like! – crasic Jun 09 '22 at 14:45
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I've an automatic wire stripper like this:

automatic wire stripper

Picture from SW-Stahl

It basically does what Peter Bennetts answer suggests and cuts / pulls the insulation apart.

I've used it like you needed before and it worked quite well, but it will also push the insulation around. If you need a very precise spacing, it will be tricky to get that right.

Arsenal
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  • This stripper works very well at the end of a wire but not in the middle of a longer wire as requested. – Uwe Jun 09 '22 at 15:37
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    Unintuitevely, this worked really well! Thank you very much! – lode Jun 09 '22 at 23:49
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    @Uwe: This was near the end of a wire, maximum sliding of the insulation is 20cm. It just works surprisingly well (stranded wire)... – lode Jun 10 '22 at 00:17
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I've done this before when I had a wire whose ends were inaccessible and I needed something to hook an oscilloscope's probe around. I used basic wire strippers like these:

I cut completely through the insulation in the middle of the wire, then made a second cut adjacent to it. This left a thin "ring" of insulation that was no longer connected to the rest. I then used an extremely sharp knife to slowly and carefully shave the top of the ring off (blade parallel to the wire, like you're peeling a piece of fruit). The remainder of the ring falls off and you're left with a gap of about 1mm in the middle of the wire.

I've done this on several occasions and it's worked well enough for my purposes. I wouldn't consider it production-quality, but for prototypes or one-off hand builds it's not terrible. The main things to keep in mind is that your tools need to be very sharp, and that it's significantly easier to damage the wire than it is during a normal stripping operation. I've only done this on solid wire, I'd imagine stranded wire would be too easily damaged by this process.

A few things to keep in mind:

  • Gaps in the middle mean the remaining insulation can move freely back and forth, which can expose wire in unexpected places and risk shorts.
  • It's possible to simply melt a section of insulation off with a lighter, but the resulting gaps tend to be very large (making the aforementioned problem worse).
  • Solder joints have very little mechanical strength. Use something like a T-splice to ensure your connections don't fall apart.
  • Insulating/protecting these T connections is very difficult. You can heatshrink over part of it, but you may have to resort to something liquid like hot glue.
bta
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    Please add a link or citation for the image that you copied into your answer. The policy for this site is that anything copied into an answer should have proper attribution. – Elliot Alderson Jun 09 '22 at 18:58
  • @ElliotAlderson - I knew I forgot something, thanks for catching that. – bta Jun 10 '22 at 00:35
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If you get the type of wire that is used for wire wrapping posts, you can compress the plastic insulation with a pair of pliers and easily peel it off, leaving the copper conductor unscathed.

Phil Freedenberg
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