Just finished wiring the garage to the house - and find that the wire is damaged! Now what?

Submitted ⁨⁨1⁩ ⁨year⁩ ago⁩ by ⁨PlutoniumAcid@lemmy.world⁩ to ⁨selfhosted@lemmy.world⁩

I mean, the simplest answer is to lay a new cable, and that is definitely what I am going to do - that’s not my question.

But this is a long run, and it would be neat if I could salvage some of that cable. How can I discover where the cable is damaged?

One stupid solution would be to halve the cable and crimp each end, and then test each new cable. Repeat iteratively. I would end up with a few broken cables and a bunch of tested cables, but they might be short.

How do the pro’s do this? (Short of throwing the whole thing away!)

source

Comments

Sort:hotnew top

myogg@lemmy.world ⁨1⁩ ⁨year⁩ ago
Higher end cable testers can show you where the break is, but it will be far more expensive that a new cable.

source
- InformalTrifle@lemmy.world ⁨1⁩ ⁨year⁩ ago
  My TP link switch can detect faults and cable length. I’m not sure it can do both together but it’s possible. Worth checking if you have a switch with those features
  
  source
  - PlutoniumAcid@lemmy.world ⁨1⁩ ⁨year⁩ ago
    Hmm, interesting! I have a Synology switch, gotta read up on its capabilities.
    
    source
- Num10ck@lemmy.world ⁨1⁩ ⁨year⁩ ago
  you can rent a time domain reflectometer for this purpose… it sends out a signal and then listens for the echos back and calculates the distance. problem is they arent accurate the first like 500 feet so you have to add a reel of 500 ft of matching cable to the end first. electrorent.com rents them.
  
  source
- azdle@news.idlestate.org ⁨1⁩ ⁨year⁩ ago
  I had an AMD Phenom-II era motherboard that claimed it would be able to do that. OP, you might be able to find an old NIC/mobo that could do this for cheap.
  
  source
ByteWizard@lemm.ee ⁨1⁩ ⁨year⁩ ago
Oscilloscope can do it - hackaday.com/…/dead-simple-time-domain-reflectome…

source
- qjkxbmwvz@lemmy.sdf.org ⁨1⁩ ⁨year⁩ ago
  Should also be able to do it with a NanoVNA or similar.
  
  source
- dipshit@lemmy.world ⁨10⁩ ⁨months⁩ ago
  That sounds triggered.
  
  source
False@lemmy.world ⁨1⁩ ⁨year⁩ ago
You can only do 100M runs max anyways, just replace the whole thing? Or is this an academic question?

source
- PlutoniumAcid@lemmy.world ⁨1⁩ ⁨year⁩ ago
  Actual, not academic. And I agree that a new cable is cheap, which is what I will do. My question is about avoiding throwing a mostly good cable in the trash.
  
  source
  - cevn@lemmy.world ⁨1⁩ ⁨year⁩ ago
    Pull it, cut into quarters. Add jacks to each end and test the lines.
    
    source
- OminousOrange@lemmy.ca ⁨1⁩ ⁨year⁩ ago
  What is an M? Miles? That doesn’t seem right.
  
  source
  - fubbernuckin@lemmy.world ⁨1⁩ ⁨year⁩ ago
    M = meters. Mi = miles
    
    source
    -> View More Comments
Steve@communick.news ⁨1⁩ ⁨year⁩ ago
If you just want some spare cable. I’d make 5x 20M pieces. The one that doesn’t work becomes 2x 10M. That bad one becomes 2x 5M … As far down as you like.

source
- pjhenry1216@kbin.social ⁨1⁩ ⁨year⁩ ago
  Isn't that almost what they suggested except starting at a different size and doing a binary search basically? You're just starting the binary search after the first step of cutting into 5 lengths instead of 2.
  
  source
SheeEttin@lemmy.world ⁨1⁩ ⁨year⁩ ago
The easiest thing to do would just be to pull it out and look at it. The break might be obvious.

source
- PlutoniumAcid@lemmy.world ⁨1⁩ ⁨year⁩ ago
  Yeah, that’s not that easy, unfortunately, because each end of the network cable passes through an insulated wall, through a hole equal to the cable width = smaller than the plug. Even if I find the break, it is likely in the outdoors part of the cable where I would want an unbroken cable without a field repair.
  
  source
  - SheeEttin@lemmy.world ⁨1⁩ ⁨year⁩ ago
    Sure, but you’re going to be pulling it out either way. When you do, inspect it.
    
    source
redcalcium@lemmy.institute ⁨1⁩ ⁨year⁩ ago
Can’t you just use a cheap non-contact voltage tester to find where the cable is damaged. Just run the tester through the cable until it suddenly stop detecting any voltage.

source
- Geometrinen_Gepardi@sopuli.xyz ⁨1⁩ ⁨year⁩ ago
  I just learned about these things today when researching for a device to test that there’s no voltage present before installing a ceiling light. Such a great innovation since it works even through insulation, so no risk of getting shocked.
  
  source
Haphazard9479@lemm.ee ⁨1⁩ ⁨year⁩ ago
How do you know the cable is damaged? If you have a toner you can hook the generator to the damaged pair and listen along the length of the cable to where the tone changes. It’s not as fool-proof as a tester, but much cheaper.

source
- PlutoniumAcid@lemmy.world ⁨1⁩ ⁨year⁩ ago
  I wanted to post a photo of my network tester but Lemmy gives me a JSON error.
  
  Anyway, the tester is supposed to light up each strand one at a time, but what I get is disco fever.
  
  source
  - Haphazard9479@lemm.ee ⁨1⁩ ⁨year⁩ ago
    I assume the disco fever is all the pairs shorted together. Is this cable buried or run through the house? I would start by redoing your ends. Make sure they are crimped fully and both sides are identical.
    
    source
    -> View More Comments
  - jake_jake_jake_@lemmy.world ⁨1⁩ ⁨year⁩ ago
    short between pairs probably. tdr (time domain reflectometer) cable tester should help locate fault. might be pinched somewhere or something else
    
    there are “casts” you can get to repair buried cable. usually used in copper telephone plant, i wouldn’t trust it to certify to a gig but you could use it for a backup link or if you play with pots at some point. or “temporary repair”
    
    source
    -> View More Comments
InverseParallax@lemmy.world ⁨1⁩ ⁨year⁩ ago
You only need 2 pairs for 100base-t, try forcing a lower negotiation, see if the pairs you need work? Maybe unbundle the other set of pairs and try them?

source
TitanLaGrange@lemmy.world ⁨1⁩ ⁨year⁩ ago
Wire tracker maybe? You might want a higher quality version than that particular one if the cable run is particularly long, one of the reviews suggest that the distance is limited.

source
- wildbus8979@sh.itjust.works ⁨1⁩ ⁨year⁩ ago
  This one here does time domain reflectiometry which will tell you exactly where the break is:
  
  www.amazon.com/…/B08M3SRB2Q/
  
  source
  - TitanLaGrange@lemmy.world ⁨1⁩ ⁨year⁩ ago
    I was curious if that would work on ethernet cable! I’ve seen it done on coax, wasn’t sure if it would work well enough on UTP to be useful outside a lab setting. Cheap too. Cool!
    
    source
    -> View More Comments