New Cat 5 wire, tests OK but doesn't work.

[bobslay]

Hi, I've just installed a new run of cat 5 cabling as the old one ran partly outside and it just gave up after 3 years of harsh winters. The cable runs about 30m from my PC to my router. I put RJ45 plugs on each end myself and I have a simple tester to test it out with the 8 consecutive lights.

The tester shows the cable is working fine but when I connect my PC to my router with it I get no connection at all, I'm clueless.

The cat5 cable was quite cheap but I thought if the cable tester said it was OK then it should work.

Any thoughts?

Thanks

 

[Chelt IT Guy]

Does your cable say CCA or LAN CABLE anywhere along its length?

I'm guessing it may be fake Cat 5e cable, CCA = Copper Coated Aluminium = very bad.

 

[kanewolf]

^ +1 be sure you have solid copper wire. Then make sure you follow the 568B wiring standard on each end -- https://en.wikipedia.org/wiki/TIA/EIA-568#Wiring

 

[jaredbaszler]

I stumbled upon this question when I was having the same problem. My tester said all was good but the lights on the network switch nor the computer would fire. I ended up re-terminating each end and now it is working. I've terminated quite a few cables in my day and never had this happen. Thanks to those who suggested re-terminating the ends. I choose that over re-running the cable through the ceiling!

 

[ggriffin.mbi]

it's possible...even likely the tester is wrong if one cable works and another does not. one thought though....does the cable pass close to any electrical lines or something with a serious magnetic field. if so current could be induced on the wire screwing up the signal.

Tester could be wrong but tester identified old cable wasn't working and the temporary one was. The route of the cable hasn't changed for three years so any magnetic/electrical interference would have been around all the time and I've been running fine at 110Mb.

If the new cable is poor quality compared to the the one it's replacing could it now be showing interference whereas before it wasn't?

Thanks for the reminder. I knew this. Duh!!, but needed to be told it again. Installed called was about 4 inches away from a small portable speaker that I believe has rare earth magnet inside. Very powerful small speaker....Had the same exact problem as described, and this fixed it for me.

 

[nigelivey]

Hi, I've just installed a new run of cat 5 cabling as the old one ran partly outside and it just gave up after 3 years of harsh winters. The cable runs about 30m from my PC to my router. I put RJ45 plugs on each end myself and I have a simple tester to test it out with the 8 consecutive lights.

The tester shows the cable is working fine but when I connect my PC to my router with it I get no connection at all, I'm clueless.

The cat5 cable was quite cheap but I thought if the cable tester said it was OK then it should work.

Any thoughts?

Thanks

You have tested continuity, this doesnt give a full green light on the cable, I would re-terminate and try again.