Repurposing Cat5E Network Cable

Hello readers

Just some random notes from my Saturday afternoon. While cleaning up the garage I found a rather long Cat5E network cable hiding from a long-forgotten project in the past:

However after trying to use it between my EtherTen and the router, the cable turned out to have a break in it somewhere. So what to do? Twentieth-century me would have just thrown it out, but that would be irresponsible. But inside that blue insulation are four twisted-pairs of 24AWG wire – perfect for prototyping and general low-voltage use:

So time to strip back the outer insulation and give the twisted-pairs their freedom:

They are a little thinner than first imagined, but how thin are they? Not being one to memorise the American Wire Gauge data I took a few quick measurements:

A quick measurement of the wire diameter without insulation. AWG specification is 0.511mm. Those digital vernier calipers were pretty sensitive so that will do. Excellent – now I have almost 120 metres of perfectly good hook-up wire. Just have to remember to test each piece before using it – that break was in there somewhere! What would that have cost me new? Local retailers (ugh) can charge over 25 centre per metre. So that’s a free lunch.

Next time you have some broken network cable… don’t throw it out – reuse it. What else can we do with the cable? Leave your suggestions in the comments below.

So have fun and keep checking into Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.


  1. I’ve been using doing that for a while now.
    They’re really useful for prototyping.

    They’re fine for breadboard work, but also for bridges on proto boards:

    You do have to be careful when soldering, though, as they heat up VERY quickly and the insulation tends to melt off extremely easily.

  2. I generally throw surplus CAT5 in the big bucket of insulated copper for my next trip to the scrap metal yard. On the other hand, I tend to collect up a few hundred pounds of the stuff per week while installing CAT6…

  3. Some concessions to the 21st Century. A few years ago Catx cable had no scrap value. Now when the copper and the insulation is reused it’s scrap value makes it worth bagging the offcuts. Adds up over the year.

  4. That cat 5 is great for sensors. I can’t imagine it having a break in the wire though. I made a light meter that tells when my solar panel is pointed straight at the sun with cat5.

  5. In general you cut the cable in smaller segments and you fix patch cords for router and patch panel connectivities. You only need a couple of RJ45’s to make them. As you mentioned above the 8 thin cables can be used in prototyping and numerous other applications.

  6. I recently used a twisted pair from a scrap of CAT5 for the temperature probe in my arduino based yogurt maker. Original project was from Make magazine. In mine I added a 16×2 LCD screen, and the temperature probe is a 10K thermistor that I sealed in heatshrink and aquarium silicone at the end of the twisted pair. This is inserted in a water bath in my crock pot to maintain a quart jar of milk/yogurt at temp for sterilization and incubation. (The CAT5 doesn’t contact the milk – just the water bath.) I have it all housed in my son’s old 2nd grade plastic pencil holder. I like reusing stuff my wife hasn’t thrown away yet!
    Anyway, I second Russ’s comment that it make nice neat 2-wire sensor cables.

  7. Twisted pair is good for RS485. It is a good comms protocol for long distance compared to RS232. It also does multi-drop which means you can snake the cable to all the points you want to cover. For example: wiring the alarm system being discussed on the forum at the moment.

  8. Telstra technicians usually carry a wire/continuity tester whereby you clip a transmitter module to one end of the cable, say at a terminal box, and then run a wireless receiving unit the audibly beeps as you run it along the cable. When the cable has a break the potential voltage drops and somehow the receiver detects this and stops beeping along cable thereafter. Useful for finding breaks in cables fixed to build form but also in this case. I don’t know what these meters are called and how much they cost but a few times I have wish I had one at my disposal.

    I plant to use cat5 to carry one-wire or some other bus (iC2 only has a short range) to communicate with a bunch of thermal sensors and a couple of water level sensors and pumps around my house and my friend found a huge continuous (hopefully) amount in a skip bin so I’d like tips and what is a suitable bus and arduino library to talk to everything.

  9. Hey, I thought of this last weekend when I needed some small wires to hook things up, it’s great! Any tip on how to remove the outer insulation the fastest/easiest? I used a wire cutter to cut along the whole cable and basically split it. It took a lot of time so is there any better way?

      • Normally on CAT5 the outer is loose and you can slide and stretch it along a couple of meters. If you need more, go another couple or even just one and you can slide it along. This leaves a tube about 1 to meters long which can be useful for other things.

Comments are closed.