How to determine if my ethernet cable is bad?

S

SlickNickTX

n3wb
Apr 27, 2023
8
12
Texas
Hello,
Just got all my wire ran through the attic and cameras installed. All cameras but one is connected.
Here's what I've tried:
  • Replaced end on one side, not the camera side
  • Tested with a cable tester for pairing
  • Tried a second camera on the same cable
  • Tried different ports in the switch and on the NVR
  • Traced the cable in the attic, no obvious outstanding kinks
    • This is a ~110' run, so I'm trying to do everything I can to not repull it.
What do you guys recommend for testing a bad ethernet cable?

SOLVED:
Alright everyone, per recommendation above and even though I tested it, it was the camera side connection. I replaced the end and it now functions as expected.
I appreciate everyone's assistance here and it goes to show, you can't always trust a cable tester...
 
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Maybe it's a CCA (Copper Clad Aluminium) cable and it can't deliver enough power over this long run?
If you plug a laptop, does the laptop's ethernet work on that cable?
If the laptop works but the cam doesn't, I'd bet on CCA, especially if your cam works on a shorter cable right besides the switch.
 
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Webfont said:
Maybe it's a CCA (Copper Clad Aluminium) cable and it can't deliver enough power over this long run?
If you plug a laptop, does the laptop's ethernet work on that cable?
If the laptop works but the cam doesn't, I'd bet on CCA, especially if your cam works on a shorter cable right besides the switch.
Click to expand...
500 ft. Blue 23/4 Solid CU CAT6 CMR (Riser) Data Cable - This is what I bought from Home Depot. I have another run that's roughly 100' with no issues.
Just tested ethernet on a laptop, it didn't work. Yikes, I think I'll end up needing to replace the line.
 
Before you rip it out, maybe try to redo your rj45 plug on the camera side? You said you redid the switch side but not the camera side. Does the rj45 cable tester detect anything or nothing flashes at all?
If it still doesn't work after that then yea, looks like the cable got stuck somewhere and got damaged while pulling it.
 
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Webfont said:
Before you rip it out, maybe try to redo your rj45 plug on the camera side? You said you redid the switch side but not the camera side. Does the rj45 cable tester detect anything or nothing flashes at all?
If it still doesn't work after that then yea, looks like the cable got stuck somewhere and got damaged while pulling it.
Click to expand...
Yeah, I just didn't do that side because I was able to test it with the cable tester this morning and it checked out. My cable tester blinks green in sync on both sides. I will reinspect the cable later today again prior to ripping it out.
 
That's odd. I've never seen a cable pass the RJ45 cable tester but not work with the laptop test. Humm.
You sure the switch port is not shutdown? Did the laptop detect a plugged in cable or no blinky lights at all? Do you have a second laptop to test if it behaves differently if you have a laptop on both ends?
 
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Keep in mind a tester simply tests continuity and that it could pass but not be sufficient for POE loading.
 
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And I've had cheap testers lie to me and run me around for a while until I realized that was the problem. I always double check mine with a known good cable now.

Definitely try reterminating the camera end before abandoning it.
 
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Mike A. said:
And I've had cheap testers lie to me and run me around for a while until I realized that was the problem. I always double check mine with a known good cable now.

Definitely try reterminating the camera end before abandoning it.
Click to expand...

This, when I installed my system the cable tester I used which wasn’t a cheapy showed all green lights but a re-term resolved the issue whereby the cam would randomly go offline.

I always check the end of the cable to make sure that all the individual wires look ok and have been pushed in far enough.

Also the plug itself can end up making a bad termination if they are either of a bad quality or if you use the wrong type for the wrong cable.
 
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SlickNickTX said:
Thanks for the feedback everyone. I will put on a new end on the camera side first. At this point, if that doesn't work I will probably re-examine the line for any kinks. If I do find a 'bad' kink, will it be sufficient to use a female to female coupler and cut the kink out? (Ex. Revo RJ45 Female to Female Indoor Network Coupler (4-Pack) NC-1BNDL4 - The Home Depot).
Click to expand...

Obviously it's not ideal to do add components in the middle of a run like that, but I think in your case it would be the next logical step if it is too much trouble to run a new wire.
 
SlickNickTX said:
Thanks for the feedback everyone. I will put on a new end on the camera side first. At this point, if that doesn't work I will probably re-examine the line for any kinks. If I do find a 'bad' kink, will it be sufficient to use a female to female coupler and cut the kink out? (Ex. Revo RJ45 Female to Female Indoor Network Coupler (4-Pack) NC-1BNDL4 - The Home Depot).
Click to expand...
If you go that route and it cures your problem, for a long term solution (if not re-pulling cable) consider protecting the coupler from the dust and thermal cycling in the attic with one of these ==>> iwillink Waterproof RJ45 Coupler, Shielded Female to Female Waterproof Ethernet Coupler, IP68 Ethernet Outdoor LAN Cable Connector for Cat5e/Cat6/Cat7 Ethernet Cable, (2 Pack)

I'd also apply dielectric grease to both sides of the coupler, regardless if you use the Home Depot (indoor) version or the more protective one.
 
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Sometimes, it's worth running a new cable. I remember having a fairly long cable that wasn't working. I found what I thought was the probable kink and cut it out and terminated both new ends, leaving two cables. One worked, one didn't. I repeated this process until I had about half a dozen shorter working cables and three shorter cables that didn't work and got pitched. My helper who ran the original cable seemed to have been a little rough on it! At least I have a good number of shorter cables for testing!

Andrew
 
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