PlutoniumAcid

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

https://lemmy.world/post/4258084

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

Sep 1, 2023 at 2:42pmWeb
Show threadmyoggSep 1, 2023
Higher end cable testers can show you where the break is, but it will be far more expensive that a new cable.
Show threadazdleSep 1, 2023
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.
Show threadNum10ckSep 3, 2023
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.
Show threadTitanLaGrangeSep 1, 2023
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.
Amazon.com

Show threadwildbus8979Sep 1, 2023

This one here does time domain reflectiometry which will tell you exactly where the break is:

www.amazon.com/…/B08M3SRB2Q/

Amazon.com

Show threadHaphazard9479Sep 1, 2023
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.
Show threadFalseSep 1, 2023
You can only do 100M runs max anyways, just replace the whole thing? Or is this an academic question?
Show threadOminousOrangeSep 2, 2023
What is an M? Miles? That doesn’t seem right.
Show threadFubber Nuckin'Sep 2, 2023
M = meters. Mi = miles
Show threadLem453Sep 2, 2023

m = meters. M = mega (x 1 000 000).

That’s why Km is 1 thousand meters and Mm is 1 million meters.

The actual unit is lower case, the multiplier is uppercase.

Show threadKethalSep 2, 2023
It’s also a lowercase k in km.
Show threadSteveSep 1, 2023
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.
Show threadpjhenry1216Sep 1, 2023
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.
Show threadredcalciumSep 1, 2023
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.
Show threadGeometrinen_GepardiSep 1, 2023
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.
Show threadInverseParallaxSep 1, 2023
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?
Show threadByteWizardSep 1, 2023
Oscilloscope can do it - hackaday.com/…/dead-simple-time-domain-reflectome…
Dead Simple Time-Domain Reflectometry With Just A Battery And An Oscilloscope

“Time-domain reflectometry” sure sounds like something that needs racks of expensive equipment to accomplish. In reality, TDR is just measuring the time between injecting a pulse into a…

Hackaday
Show threadqjkxbmwvzSep 1, 2023
Should also be able to do it with a NanoVNA or similar.
Show thread𝕯𝖎𝖕𝖘𝖍𝖎𝖙Jan 3, 2024
That sounds triggered.