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A few years ago I bought what should be a 45m flat Ethernet cable. After a long period of disuse the cable has gotten very tangled but I need to use it again. I've unknotted the cable so it is now one long cable but the cable is incredibly twisted:

very twisted very twisted 2

I've tried to very slowly untwist the cable starting from one end, but that just seems to make the problem worse. After a certain point it gets harder and harder to untwist and then I can't untwist it anymore, and then the rest of the cable gets even more twisted. No matter which way I twist the end of the cable just seems to get even more twisted.

enter image description here

Is there a clever way to untwist this cable? Or should I cut my losses and just buy a new one?

Lieu Zheng Hong
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    Flat cables like that get deformed and you'd have to heat them to soften them to fix the problem. This isn't a home improvement project, though. – isherwood Oct 05 '20 at 16:14
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    Pull the cable through your fingers. The friction will generate a bit of heat which will help the cable soften and return to its flat state. You'll have to pull the same stretch over and over and over and over... While you're doing this, you'll be _adding_ that twist to the rest of the cable, so you'll need to stop every few feet to "whip" the twist out. All in all, if you _really_ need it to lay flat, buy a new one. If not, use it as it - the electrons don't really care how twisted the housing is... – FreeMan Oct 05 '20 at 16:31

2 Answers2

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Well, the good news is it does not appear that you've passed into "throw it away" levels of twisted yet. I've had users do things to innocent cables that I can't quite believe. I find out about them when the cable fails, usually.

Find a stairwell, or some other place you can let the cable dangle, hold, and wait. Since you probably don't have a 45m stairwell handy, you'll have to work in sections. Starting from the end is a problem unless you can let the whole thing dangle - you want to start as far into the middle as you can and let the end spin free, so that the twist gets "worked out".

Another approach is to wind the untwisted section of cable onto a core of some sort (essentially a small cable spool) and to spin that as needed to remove twist as you wind it on - you'll need to keep light tension on it so it can't snarl - you can tape it if you want to pause while working. Important to then unroll it, NOT spiral it off the side of the spool. Still likely to be easiest if you can hang the unspooled cable as much as possible so it twists freely.

Once you get it sorted, you may also want to look up various methods of coiling cables without adding twist when coiling. Various ways work, and the one I prefer may not be the one you prefer.

Ecnerwal
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    Excellent answer. This is why cable and rope is wound on a drum, and then unwound in teh reverse fashion, to prevent corkscrewing. – Criggie Oct 15 '20 at 05:07
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Make a couple of cable holders that are shaped like the picture shows.

You can probably buy something like that for christmas light strings or extension cords.

Wind about 41 m of the twisted cable onto one, and secure with a rubber band, or have someone hold it.

Untwist the remaining length and wind onto the second, take-up holder, then secure with a rubber band on the take-up holder.

Unwind 4 more meters from the first holder and repeat.

Draping the cable over a ceiling hook, or down a stairway helps because the take-up holder can spin freely.

enter image description here

jsotola
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