Cat cable tester question - Solved

Larry Sheehan · Dec 16, 2020

I have a cheapo cat cable continuity tester. Using a premade CAT5E STP cable it shows all 4 pairs connected as well as the shield (as Expected)

Now I'm repairing my cat5e STP snake. If the shield is not connected at both ends, this tester shows all 4 pairs connected properly. If I connect shield to both ends the tester shows Pin 8 open!!?

I put an ohmmeter on the cable and all wires are intact (continuity checks out).

Have you any idea what this could be?

Whoops · Dec 16, 2020

Larry Sheehan said:
I put an ohmmeter on the cable and all wires are intact (continuity checks out).

That seems to be the best final testing stage. If you have continuity between all wires and no shorts , all is good

Larry Sheehan said:
I have a cheapo cat cable continuity tester.
Have you any idea what this could be?

Probably the cheap tester has some internal fault. Maybe some short with Pin8 to the the shield?

Larry Sheehan · Dec 17, 2020

Whoops said:
That seems to be the best final testing stage. If you have continuity between all wires and no shorts , all is good

Probably the cheap tester has some internal fault. Maybe some short with Pin8 to the the shield?

Initially I suspected the tester, but when a known good cable tested out correctly, I figured the tester was probably OK.

Whoops · Dec 17, 2020

Larry Sheehan said:
Initially I suspected the tester, but when a known good cable tested out correctly, I figured the tester was probably OK.

You said that a "known good cable" with shields tested "incorrectly" in the cheap tester...

Larry Sheehan · Dec 18, 2020

Whoops said:
You said that a "known good cable" with shields tested "incorrectly" in the cheap tester...

If i did, I meant correctly, but I checked my original post and I think I said all pairs and shield showed continuity on the premade (known good) cable.

Larry Sheehan · Dec 27, 2020

Larry Sheehan said:
If i did, I meant correctly, but I checked my original post and I think I said all pairs and shield showed continuity on the premade (known good) cable.

I bought a better tester, and it appears the my original tester was in fact bad. I thought I had verified it was OK , but did that using a shorter cable. The new tester reports the length of the shorter cable 25 feet correctly and the longer (293 feet) cable as properly wired.

Sorry for the confusion.